Rivas-Castillo and Rojas-Avelizapa: Microbiological approaches for the treatment of spent catalysts



Introduction

Catalysts are broadly used in the chemical and oil industries to upgrade diverse types of important processes. These industrial catalysts regularly consist of metals supported on porous materials like alumina or silica. During operations, these catalysts deactivate with their periodical use (Jong, Rhoads, Stubbs & Stoelting, 1992), through structural changes, poisoning, or the deposition of external materials, and then sent to on-site or off-site regeneration plants. However, the regeneration of the spent catalysts that are discarded from industrial processes can only be performed for a limited number of times and it is only possible for some of these residues. Thus, when regeneration is not possible because the catalyst can no longer perform its original duty, is referred to as “spent catalyst”, and is considered as a solid waste.

Catalysts are used in a broad range of industrial processes and in elevated amounts, commonly to produce clean fuels and many other valuable products (Marafi, Stanislaus &Furimsky, 2010; Stanislaus, Marafi & Rana, 2010). It has been reported that spent hydroprocessing catalysts are the major solid wastes of refining industries, representing the main contributors to the generation of spent catalysts (Liu,Yu & Zhao, 2005), being annually produced between 150,000-170,000 tonnes of spent hydroprocessing catalysts worldwide (Chiranjeevi, Pragya, Gupta, Gokak & Bhargava, 2016), and the amount will continue to increase as new hydrotreatment processes are needed to meet the growing demand. Spent catalysts have been classified as hazardous residues by the Environmental Protection Agency (EPA) in the USA due to their dangerous self-heating liability and their highly toxic content (Eijsbouts, Battiston & van Leerdam, 2008), caused by the simultaneous presence of metals and other non-metallic elements, such as Al, V, Mo, Co, Ni, As and Fe, and elemental sulfur, carbon and oils, respectively (Mishra, Kim, Ralph, Ahn & Rhee, 2008). Besides, the metals contained in spent catalysts can be leached after disposal due to water action, generating pollution dispersion (Marafi & Stanislaus, 2007; 2008a,b), and/or may react with other environmental components like oxygen, which can cause the release of toxic gases such as H2S, HCN, or NH3 (Noori Felegari, Nematdoust Haghi, Amoabediny, Mousavi & Amouei Torkmahalleh, 2014).

Spent catalysts can be moderately regenerated to be re-used as catalysts for other processes (Kim & Shim, 2008a,b; Shim & Kim, 2010; Bitemirova, Alihanova, Spabekova, Shagrayeva & Ermahanov, 2015), treated before final disposal for the recovery of valuable metals, or directly disposed in landfills as solid wastes, although this latter option may be the least recommended one, due to environmental constraints. Considering the worrying exhaustion of natural resources and the elevated environmental pollution nowadays, the recovery of metals from spent catalysts has been under the scope in the last years, as they represent a source of commercially valuable metals, offering a viable alternative for the recovery of the metallic components contained therein, in order to reduce the amount of disposed waste and promoting the conservation of natural resources.

Recycling of spent catalysts

There have been suggested interesting options for the usage of spent catalysts as raw materials for the production of other valuable products, which may also represent an attractive option for the recycling (instead of disposal) of these types of residues. Diverse materials have been prepared using spent catalysts, such as abrasive components for the ceramic and refractory industries (Zeiringer, 1979), aggregates for concrete production (Stanislaus, Gouda & Al-Fulaij, 1998) or in road bases and sub-bases for construction aplications (Taha, Al-Kamyani,Al-Jabri, Baawain & Al-Shamsi, 2012), production of refractory bricks and cement (Vargas et al., 2018), as a component in asphalt mixtures (Yoo, 1998), anorthite glass-ceramics for application as an electrical insulating material (Su, Chen & Fang, 2001), as a wastewater filtering agent (Sanga & Nishimura, 1976), in combination with activated sludge for biological treatment of wastewater from municipal and industrial sources (Liles & Schwartz, 1976) and properly as catalysts for other applications, including the reduction of nitrogen oxides (Choi, Kunisada, Korai, Mochida & Nakano, 2003). However, most of the processes regarding these recycling options are still under study in a laboratory stage (Marafi & Stanislaus, 2008a).

Traditional techniques for metal extraction from spent catalysts

For the recovery of precious metals, plasma technologies have been assessed in a wide range of spent catalysts, especially to recover Pt group metals from these high metal content residues generated in both automotive and diverse industrial processes, where the same metal recovery procedure can be used to deplete the hazardous properties of the spent catalyst while recovering the metals contained therein for their reutilization (Rui,Wu, Ji & Liu, 2015). Also, hydrometallurgical (treatment in organic and inorganic aqueous medium), pyrometallurgical (heating, roasting), and chelating agent methods for the treatment of spent catalysts and metal recovery are available, and were reviewed in detail by Akcil, Vegliò, Ferella, Okudan &Tuncuk (2015). Although these conventional approaches confer an economic advantage, they generate large volumes of potentially hazardous wastes and emission of harmful gases (Llanos & Lacave, 1986), which involve high costs and environmental risks. Thus, new alternatives are needed to develop eco-friendly solutions associated with the treatment of this kind of residues (Marafi & Stanislaus, 2008a,b).

Microbiological approaches for the treatment of spent catalysts

As it has been previously sustained, biotechnological methods may represent a promising alternative for the treatment of spent catalysts (Noori-Felegari, et al., 2014), due to important microbial properties, like their ability to survive and adapt to elevated metal concentrations, and also to transform solid non-essential metals into soluble and extractable elements that could be recovered (Yang, Qi, Low & Song, 2011; Sahu, Agrawal & Mishra, 2013). In this regard, research has also been performed to develop bio-approaches for the mining industry. To date, several bio-techniques comprised under the term of "biohydrometallurgy" have been investigated, standardized, or even industrially exploited (Mishra, Kim, Ralph, Ahn & Rhee, 2007), including: a) the removal of metals contained in low-grade ores or low-grade mineral resources (Brombacher, Bachofen & Brandl, 1997; Olson, Brierley & Brierley, 2003) and residues (Krebs, Brombacher, Bosshard, Bachofen & Brandl, 1997) by the action of microorganisms, b) the recovery of these metals, and c) the subsequent metal purification steps.

Bioleaching is one of the techniques included in biohydro-metallurgical applications (Asghari, Mousavi, Amiri &Tavassoli, 2013), which enables metal recycling by processes similar to the ones found in the natural biogeochemical cycles (Brierley, 2008), being demonstrated its suitability for the successful removal of metals contained in diverse kinds of solid industrial wastes, like fly ash (Burgstaller & Schinner, 1993; Bosshard, Bachofen & Brandl, 1996; Brombacher et al., 1997; Xu, Ramanathan & Ting, 2014), sewage sludge (Chartier & Couillard, 1997), spent batteries (Cerrutti, Curutchet & Donati, 1998), electronic scrap materials (Brandl, Bosshard & Wegmann, 2001), and spent catalysts (Santhiya & Ting, 2005; Marafi & Stanislaus, 2008b). Besides, bioleaching has also been applied for the bioremediation of contaminated soils (Chen & Lin, 2004; Gadd, 2004) and sediments (Beolchini, Rocchetti, Regoli & Dell’ Anno, 2010b). It is important to mention that bioleaching approaches can be considered as more eco-friendly techniques, whose development is important to attenuate the negative environmental impacts of the traditional methods applied to date (Mishra et al., 2007), and have been gaining importance due to their following demonstrated advantages in comparison to conventional processes of metal extraction: besides they represent environmental-friendly technologies, they also involve lower costs and lower energy requirements, are simpler and cheaper to perform and maintain, they may operate at environmental pressure and non-excessive temperatures, they present higher efficiencies in terms of heavy metal removal and non-strict requirements of raw material composition, they have been successfully applied at industrial scale for low grade ores (concentration of metals < 0.5 wt %) and are applicable for highly contaminated materials. In addition, these approaches do not generate hazardous emissions (Akcil et al., 2015). Above all, no chemical reagents are needed for the bioleaching process, as these processes are biologically induced with no requirement of a continuous delivery of other raw materials to the processing plant, which implies a reduction in the environmental and economical impacts, as it has been stated the diminished production of carbon emissions due to transportation, and also that raw materials represent a significant part (52.2%) of chemical leaching costs for spent hydrogenation catalysts (Yang et al., 2011). It has also been established that carbon emissions have the major contribution, together with energy, on the impact of these chemical leaching procedures, in terms of global warming potential (Beolchini, Fonti, Dell’Anno, Rocchetti &Vegliò, 2012).

During bioleaching processes, the leached and recovered highly valuable metals may be recycled and re-used as secondary raw materials (Bosshard et al., 1996; Brandl et al., 2001). Thus, a lot of the large-scale bioleaching industrial facilities are located in developing countries, mainly due to two important factors: 1) the significant mineral reserves and mining industries they have; and 2) the simplicity and low-cost requirements of bioleaching techniques (DaSilva, 1981; Gentina & Acevedo, 1985; Warhurst, 1985; Acharya, 1990; Acevedo, Gentina & Bustos, 1993; Acevedo, 2002). This is the case of Mexico, and also of countries like Chile, Indonesia, Peru and Zambia. In the specific case of Mexico, the company Peñoles S.A. has established an integrated process consisting of bioleaching, solvent extraction and electrowinning, successfully generating 500 kg of Cu per day (Acevedo, 2002).

Microorganisms used for the biotreatment of spent catalysts

During the growth of microorganisms, some formed metabolites may be useful to perform the extraction of valuable metals from waste materials, due to their acidic nature or their complex formation capability. As illustrated in Figure 1, the ability of diverse microorganisms to remove and leach metals contained in solid materials may be due to: a) the transformation of organic or inorganic acids; b) oxidation and reduction reactions; and c) the production of complexing agents. Metals can be leached either directly, by the physical contact between microorganisms and solid materials, or indirectly, by the bacterial oxidation of an element (for example Fe2+ to Fe3+), which catalyses metal solubilization as an electron carrier (Krebs et al., 1997). Specifically, diverse microorganisms have been analyzed to determine their metal removal capabilities from spent catalysts, comprising bacteria, archaea and fungi. The compiled results reported in this respect have been previously addressed by Lee & Pandey (2012), Srichandan, Kim, Gahan & Akcil (2013), Mishra & Rhee (2014) and Akcil et al. (2015). Additionaly to previous compendiums, Table I presents an upgrade of the results reported to date. Furthermore, the removal abilities and characteristics of the diverse microorganisms that have been used for this purpose are described below.

Figure 1

Mechanisms of metal bio-removal by microorganisms: A) Production of acids for direct or indirect biolixiviation; B) Oxidation and reduction reactions; or C) Production of metal (M) complexing agents. Figure designed by the authors.

1405-888X-tip-23-e20200214-gf1.png

Table I

Metal removal from spent catalysts by different microorganisms.

Microorganism Removal efficiency (%) Spent catalyst type Reference
Al Fe Ni Mo V
Archaea
Acidianus brierleyi 67 100 100 100 -a Hydrotreating catalyst Bharadwaj & Ting, 2013
Acidianus brierleyi 35 - 69 83 - Hydrocracking catalyst Gerayeli et al., 2013
Fungi
Acremonium sp. - - 21 - 23.5 Hydrocracking catalyst Gómez-Ramírez et al., 2015b
Aspergillus niger 30 23 9 - 36 Fluid catalytic cracking catalyst Aung & Ting, 2005
Aspergillus niger 54.5 - 58.2 82.3 - Refinery processing catalyst Santhiya & Ting, 2005
Aspergillus niger 65.2 - 78.5 82.4 - Refinery processing catalyst Santhiya & Ting, 2006
Aspergillus niger 13.9 - 45.8 99.5 - Hydrocracking catalyst Amiri et al., 2012
Penicillium sp. - - 0.0 - 24 Hydrocracking catalyst Gómez-Ramírez et al., 2015b
Penicillium simplicissimum 25 100 66.4 92.7 - Hydrocracking catalyst Amiri et al., 2011
Rhodotorula mucilaginosa - - 87 - 48 Petroleum catalyst Arenas-Isaac et al., 2017
Rhodotorula mucilaginosa - - 9.4 - 2 Hydrocracking catalyst Gómez-Ramírez et al.,2014
Bacteria
Acidithiobacillus spp. - - 85 26 92 Hydroprocessing catalyst Kim et al., 2008
Acidithiobacillus spp. - - 88 46 95 Petroleum catalyst Pradhan et al., 2009
Acidithiobacillus thiooxidans - - 88.3 58 32.3 Refinery catalyst Mishra et al., 2007
Acidithiobacillus thiooxidans - - 88 46 95 Hydroprocessing catalyst Mishra et al., 2008
Acidithiobacillus thiooxidans 2.4 - 16 95 - Naphta hydrotreating catalyst Gholami et al., 2015
Acidithiobacillus thiooxidans 5.7 0.8 0.0 0.0 - Hydroprocessing catalyst Rivas-Castillo et al., 2018
Acidithiobacillus thiooxidans 0.4 0.8 0.1 0.0 - Automotive catalyst Rivas-Castillo et al., 2018
A. thiooxidans and A. ferrooxidans 10.0 - 58.6 5.8 33.4 Refinery catalyst Pathak et al., 2015
A. thiooxidans, A. ferrooxidans and L. ferrooxidans - - 83 40 90 Hydroprocessing catalyst Beolchini et al., 2010a,b, 2012
Acidithiobacillus spp. and Sulfobacillus thermosulfidooxidans 38 - 97 - 91 Petroleum catalyst Srichandan et al., 2014
Bacillus megaterium - - 10 - 6.5 Hydrocracking catalyst Arenas-Isaac et al., 2017
Bacillus megaterium 0.0 - 22.6 6.0 46.4 Hydrocracking catalyst Rivas-Castillo et al., 2017a
Bacillus megaterium 0.8 - 0.5 - 1.6 Petroleum catalyst Rivas-Castillo et al., 2019
Cupriavidus metallidurans 0.0 0.0 0.0 17.5 15.9 Petroleum catalyst Rivas-Castillo et al., 2017b
Microbacterium liquefaciens - - 40.6 - 9.3 Petroleum catalyst Rojas-Avelizapa et al., 2015
Microbacterium liquefaciens - - 45 - 25 Petroleum catalyst Gómez-Ramírez et al., 2015a
Microbacterium spp. - - 51 - 41.4 Petroleum catalyst Gómez-Ramírez et al., 2015a

[i] a- Not Determined.

Archaea

Some reports have already suggested the potential of thermophilic microorganisms for the bioleaching of spent catalysts (Deveci, Akcil & Alp, 2004). The sulfur-oxidizing extreme thermophile Acidianus brierleyi, which grows best in pH 1-2 and temperature 60-70 °C, has been identified with a good potential to perform the recovery of metals contained in minerals (Konishi, Tokushige, Asai & Suzuki, 2001). Also, it was shown that when exposed to the presence of spent hydrotreating catalysts, in a pulp density between 0.6-1% (w/v), A. brierleyi is capable of sustaining growth, and furthermore, metal solubility was observed in the ranges of 35-67% Al, 100% Fe, 69-100% Ni, and 83-100% Mo (Bharadwaj & Ting, 2013; Gerayeli, Ghojavand, Mousavi, Yaghmaei & Amiri, 2013). These authors, also demonstrated that Ni and Mo bioleaching using this microorganism was more effective than chemical leaching using commercial sulfuric acid (Bharadwaj & Ting, 2013).

Fungi

Besides their intrinsic removal capabilities, especially the incremented tolerance of microbial strains isolated from extremely polluted environments, some microorganisms possess the ability to survive to high concentrations of toxic heavy metals, by adaptation or mutation processes (Konishi et al., 2001; Valix & Loon, 2003; Bharadwaj & Ting, 2013; Gerayeli et al., 2013), which may confer them with exceptional survival advantages. For this reason, some researchers have inquired around this idea in order to obtain heavy metal-tolerant fungal strains, including descendants from Penicillium funiculosum, Aspergillus foetidus and Penicillium simplicissimum, specifically for the bioleaching of Ni laterite ores and low-grade ore materials (Valix & Loon, 2003; Santhiya & Ting, 2006; Liu et al., 2008); and Acremonium spp. and Penicillium spp. strains isolated from a high metal content soil have also been assessed for their metal removal capabilities from an hydrotreating spent catalyst (Gómez-Ramírez, Plata-González, Fierros-Romero & Rojas-Avelipaza, 2015b). Amiri, Yaghmaei & Mousavi (2011) adapted the fungus P. simplicissimum to the metals Ni, Mo, Fe, and W, which were known to be present in a W-rich spent hydrocracking catalyst, and then performed a spent catalyst bioleaching assay using one-step and two-step processes, as well as assessing leaching efficiencies using the spent medium, at pulp densities between 1-5% (w/v). They reported the optimum removal efficiencies of 25% Al, 100% Fe, 66.4% Ni, 92.7% Mo, and 100% W, and also stated that an optimized two-step bioleaching process may be a suitable alternative to conventional treatment methods. As well, Santhiya & Ting (2006) performed the adaptation of Aspergillus niger to Ni, Mo and Al in order to assess the tolerance increment of this fungus to a spent refinery processing catalyst, observing that the Ni:Mo:Al-adapted strain extracted 78.5% Ni, 82.4% Mo and 65.2% Al, which represented higher Al and Ni removals compared to the ones with the non-adapted culture, demonstrating that adaptation may be a promising approach for the biotreatment of spent catalysts and high metal content wastes.

A.niger is one of the most widely used fungus for bioleaching approaches (Santhiya & Ting, 2005), and has also been used in the production of organic acids, such as citric acid (Grewal & Kalra, 1995), oxalic acid (Strasser et al., 1994) and gluconic acid (Dronawat, Svihla & Hanley, 1995), which can be used as lixiviants of heavy metals contained in ore materials and solid wastes (Bosshard et al., 1996; Groudev, Spasova, Georgiev & Nicolova, 2014). Results showed that the presence of a spent catalyst may cause a decrease in the biomass yield of this fungus but an increase in its oxalic acid secretion (Santhiya & Ting, 2005). The extraction of metals by A. niger from diverse spent catalysts in the presence of pulp densities between 1-3% (w/v) were in the range of 13.9-54.5% Al, 9-58.2% Ni, 82.3-99.5% Mo, and 36% V (Aung & Ting, 2005; Santhiya & Ting, 2005; Amiri, Mousavi, Yaghmaei & Barati, 2012). Besides, it was also demonstrated the lixiviation ability of Fe (23%), and Sb (64%) by A. niger from a spent catalyst, also reporting that its metal extraction efficiency tends to decrease with increased pulp density, and as in the case of other microbial bioleaching processes (Bharadwaj & Ting, 2013), this biotechnological approach allowed higher metal extraction yields than chemical leaching (Aung & Ting, 2005).

The yeast Rhodotorula mucilaginosa has been also tested for its metal removal capability, and it has been reported that a strain isolated from a filter plant of a Cu mine located in the Northwest of Argentina is capable of accumulating up to 44 % of Cu from a medium supplemented with 0.5 mM CuSO4 (Villegas, Amoroso & Figueroa, 2005). Also, a report has been published where the heavy metal-resistant R .mucilaginosa strain UANL-001L, isolated from the Northeast region of Mexico, presented a Minimum Inhibitory Concentration (MIC) of 1000 mg/L to Zn and Pb, and MICs between 600 and 800 mg/L to Cr (III and VI), Cu, Cd and Ni. Also, this strain can produce an exopolysaccharide (EPS) during growth, which production is enhanced by the presence of metals like Zn (II), Pb (II), Cr (VI), Cu (II), Ni (II) and Cd (II) (Garza-González et al., 2016). Besides, another R. mucilaginosa strain, coded as MV-9K-4, was isolated from a high metal content site in Guanajuato, Mexico, and when exposed to a spent catalyst at 16% (w/v) pulp density, presented the ability to remove 87% Ni and 48% V, being one of the most relevant strains in terms of its Ni and V removal capability of all the strains tested that were isolated in-situ from different mining sites (Arenas-Isaac et al., 2017).

Bacteria

Most of the studies about the biotreatment and extraction of valuable metals from spent catalysts have been focused on the use of the acidophilic sulfur-oxidizing bacteria Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans (Rohwerder, Gehrke, Kinzler & Sand, 2003; Beolchini, Fonti, Ferella &Vegliò, 2010a; Hong & Valix, 2014) in liquid and column systems (Pathak, Srichandan & Kim, 2019), mainly because they present biolixiviating properties. Besides, these microorganisms are autotrophic and tolerate high concentrations of heavy metals. The usefulness of Acidithiobacillus species for metal solubilization from ores and solid wastes is closely related to their ability to acidify their habitat by the production of special metabolic byproducts as leaching agents, like sulfuric acid and sulfur-oxidation intermediates (Sand, Gehrke, Jozsa & Schippers, 2001).

A. thiooxidans and A. ferrooxidans have been previously reported with the ability to reduce V (V) to V (IV) in the presence of elemental sulphur (Brandl et al., 2001; Bredberg, Karlsson & Holst, 2004), and studies have also demonstrated the applicability of these sulfur-oxidizing bacteria for the release of metals contained in different spent catalysts at diverse pulp densities, being capable of removing Ni, V and Mo in the ranges of 0.1-99%, 25-95%, and 25-95%, respectively (Mishra et al., 2007, 2008; Pradhan, Mishra, Kim, Chaudhury & Lee, 2009; Gholami, Borghei & Mousavi, 2011; Gholami, Razeghi & Ghasemi, 2015; Pathak, Srichandan & Kim, 2015; Ferreira, Sérvulo, Ferreira & Oliveira, 2016; Rivas-Castillo, Gómez-Ramírez, Rodríguez-Pozos & Rojas-Avelipaza, 2018). Both bacterial species, A. thiooxidans and A. ferrooxidans, seem to present similar leaching kinetics under the same conditions of pH, nutrient concentration, pulp density, particle size and temperature, and their dissolution kinetics were reported to be higher for Mo than for Ni and V (Pradhan et al., 2009). Also, Acidithiobacillus spp. Al and Co removal capabilities were reported between 0.4-89% and 83-96%, respectively (Gholami et al., 2011, 2015; Pathak et al., 2015; Sharma et al., 2015; Ferreira et al., 2016; Rivas-Castillo et al., 2018). Both Mishra et al. (2008) and Pradhan et al. (2009) reported that two-step processes may be the most suitable to increase the bioleaching efficiencies of Acidithiobacillus spp., due to the general advantages of two-stage processes, as that the independent generation of the lixiviating agent separates the bioprocess from the chemical process, making it possible to optimize each step independently in order to maximize productivity (Mishra et al., 2008), and they also stated that higher waste concentrations can be treated with a two-step procedure, instead of a one-step process, to increase metal removal yields (Johnson, 2013).

Likewise, investigations with acidophilic bacteria have been conducted using mixed cultures of Acidithiobacillus spp., A. thiooxidans and A. ferrooxidans (Kim, Mishra, Park, Ahn & Ralph, 2008), and A. ferrooxidans, A. thiooxidans and Letosphirilum ferrooxidans (Beolchini et al., 2012), grown in the presence of a broad range of pulp densities, in the range of 0.15-10% (w/v) of spent catalysts. Results showed the removal of Ni, Mo and V to the extent of 83-85%, 26-40% and 90-92%, respectively, emphasizing the potential of this type of microorganisms to remove significant amounts of Ni and V, and a less amount of Mo. Furthermore, assays have been made to determine the leaching potential of moderate thermophilic bacteria using a mixed consortium of moderate thermophilic iron and sulphur oxidizers: Sulfobacillus thermosulfidooxidans, Acidithiobacillus caldus, A. ferrooxidans, and A. thiooxidans, in the presence of 10% (w/v) pulp density of a spent catalyst, where higher recoveries of Ni (92-97%) and V (81 - 91%) were obtained, whereas leaching of Al (23-38%) was lowest in all the assessed particle sizes of the spent catalysts, suggesting that bioleaching using a consortium of moderate thermophilic microorganisms may be also an efficient process for the recovery of metals from spent catalysts (Srichandan et al., 2014).

Besides sulfuric acid, which is the mainly acid found in bioleaching processes due to the metabolism of Acidithiobacillus species (Sand et al., 2001; Rawlings, 2002), other organic acids may be produced by bacterial and fungal metabolisms, that may also promote metal removal from solid materials by acidification or complex and chelate formations (Burgstaller & Schinner, 1993). One of these cases is the solubilization of metals by Hydrogen Cyanide (HCN), which may be produced during microbial growth (Faramarzi & Brandl, 2006). As cyanide forms water-soluble metal complexes of high chemical stability, it may be a promising strategy for the recovery of metals that are removed from solid residues (Brandl, Lehmann, Faramarzi & Martinelli, 2008; Motaghed, Mousavi, Rastegar & Shojaosadati, 2014). However, it is known that working with cyanide compounds present the inconvenience of HCN volatilization, which is a potent hazardous gas (Luque-Almagro, Moreno-Vivián & Roldán, 2016). It has been reported that B. megaterium strain PTCC 1656 may produce HCN when grown under glycine-rich conditions (Faramarzi, Stagars, Pensini, Krebs & Brandl, 2004; Faramarzi & Brandl, 2006).Thus, this strain was grown under these conditions in the presence of a spent refinery catalyst rich in Pt and Re at pulp densities of 1-10% (w/v), showing that after 7 days in the presence of 4% (w/v) pulp density of the residue, the maximum extraction for Pt and Re corresponded to 15.7% and 98%, respectively (Motaghed et al., 2014).

To address the hypothesis that native microorganisms from high metal content sites may present evolutionary advantages in reference to resistance and metal removal capabilities in the presence of spent catalysts, Arenas-Isaac et al. (2017) performed an in-situ sampling in four different mining sites in Guanajuato, Mexico, and demonstrated that all isolates recovered from these locations presented tolerance limits greater than 200 ppm for Ni and V. Moreover, when the strain coded as MV-9K-2, identified as Bacillus megaterium, was exposed to a spent catalyst at a pulp density of 16% (w/v), it was able to remove 2541.7 mg/kg of Ni and 3750 mg/kg of V, corresponding to 10% and 6.5% of each metal, respectively, showing the enhanced potential of MV-9K-2 for Ni and V removal from high metal content residues (Arenas-Isaac et al., 2017). Also, B. megaterium strain MNSH1-9K-1, which was isolated during the same in-situ sampling, has been identified for its ability to remove up to 0.8% Al, 0.5% Ni, 46.4% V and 6% Mo from high metal content spent catalysts (Rivas-Castillo, Orona-Tamayo, Gómez-Ramírez & Rojas-Avelipaza, 2017a; Rivas-Castillo, Guatemala-Cisneros, Gómez-Ramírez & Rojas-Avelipaza, 2019).

Another in-situ isolated microorganism is Cupriavidus (Wautersia, Ralstonia, Alcaligenes) metallidurans strain CH34, which is widely known for its multiple heavy metal resistance and for possessing a proven capability for simultaneous heavy metal accumulation. When in contact with a spent catalyst, this strain was able to remove 2111.20 ± 251.81 mg/kg of V and 931.56 ± 95.38 mg/kg of Mo, representing the 15.93% and 17.58% of each metal content in the residue, respectively (Rivas-Castillo et al., 2017b). On the other hand, it has been reported that Microbacterium spp. have been found in metal contaminated sites, and some isolates present enhanced resistance to As (Kaushik et al., 2012), and resistance and removal capabilities for U (Islam & Sar 2016). Also, some Microbacterium spp. strains were isolated in-situ from high metal content sites in Guanajuato, Mexico (Arenas-Isaac et al., 2017), and three isolates, namely Microbacterium liquefaciens MNSH2-PHGII-2, Microbacterium oxydans MNSH2-PHGII-1, and Microbacterium oxydans MV-PHGII-2 were evaluated on their potential for Ni and V removal contained in different spent catalysts, at pulp densities of 8 and 16% (w/v). Results showed that these strains present the ability to remove Ni (16-45.4%) and V (9.5-41.4%) contained in the high metal content residues, varying in their Ni and V removal capabilities between the strains isolated from the same site, or even between the strains of the same specie isolated from different sites (Arenas-Isaac et al., 2017; Gómez-Ramírez, Flores-Martínez, López-Hernández & Rojas-Avelipaza, 2014; Gómez-Ramírez, Montero-Álvarez, Tobón-Avilés, Fierros-Romero & Rojas-Avelipaza, 2015a). Furthermore, M. liquefaciens strain MNSH2-PHGII-2 was assessed for its ability to remove Ni and V from a spent catalyst at 80% (w/v) pulp density in a glass-column system at laboratory conditions, showing a removal capability of 40.6% and 9.3% for Ni and V, respectively (Rojas-Avelizapa, Gómez-Ramírez & Alamilla-Martínez, 2015).

Heterogeneity of the spent catalysts used for biotechnological experimentation

It is notorious that the diverse spent catalysts that have been used for metal removal experimentation are originated from different sources, and both their metal compositions and the pulp densities used for this purpose are different among the studies, as it is shown in the data presented in Table II. Besides, the experimental conditions reported differ between the assays, and it has been demonstrated that metal uptake and spent catalyst biotreatment efficiencies may vary with metal and pulp density concentrations, particle size, pH, temperature, incubation time, growth phase of the microorganisms used and inoculum concentration (Srichandan et al., 2014; Fan, Onal Okyay & Rodrigues, 2014; Motaghed et al., 2014). Thus, all these variables may represent an inconvenience for the accurate comparison of the metal removal abilities of the different microorganisms that have been tested. In addition, the removal capabilities are commonly reported in removal percentage, which may be tricking, as they represent the percentage content from varied metal compositions found in the different spent catalysts, and at diverse pulp densities. For example, it is reported that B. megaterium strain MV-9K-2 is able to remove only 10% of Ni from a spent catalyst, which although it may be seen as a low percentage, it represents 2541.7 mg/kg removed from a spent catalyst that contains 24,822 mg/kg of Ni, in contrast to M. liquefaciens strain MNSH2-PHGII-2 that was able to remove 45% of Ni from a spent catalyst that only contains 427.5 mg/kg of Ni (Arenas-Isaac et al., 2017). Also, it has been previously observed that diverse genera of microorganisms present different metal removal preferences, that may also depend on the total metal charge, and the amounts and the types of metals and other components (as hydrocarbons) present in the solid residues (Rivas-Castillo et al., 2017a,b). Thus, the establishment of similar experimental conditions is essential in order to perform a proper comparison of the metal removal efficiencies and metal removal selectivity between different microorganisms.

Table II

Compositions and pulp densities of spent catalysts used for biotreatment experimentation.

Metal composition (wt %) Pulp densities (% w/v) Reference
Al Fe Ni Mo V
17.50 0.56 0.26 - 0.39 1 - 12 Aung & Ting, 2005
19.20 49.00 2.10 8.50 -a 1 Bharadwaj & Ting, 2013
39.40 - 0.06 8.00 - 0.15 - 4 Gholami et al., 2011
10.97 0.03 2.48 3.27 5.76 8 Arenas-Isaac et al., 2017
10.31 0.40 0.04 0.002 0.22 16 Gómez-Ramírez et al., 2014
14.20 1.50 1.70 1.20 7.70 0.5 - 5 Mishra et al., 2008
15.31 - 2.70 2.34 8.76 1 Pathak et al., 2015
19.50 0.30 2.00 1.40 9.00 5 - 25 Pradhan et al., 2009, 2010
33.30 - 6.09 13.72 - 1 Santhiya & Ting 2005, 2006
15.70 - 3.06 2.03 11.30 10 Srichandan et al., 2014
10.12 0.62 0.16 0.53 1.32 1 - 10 Rivas-Castillo et al., 2017a
13.33 0.41 0.01 0.00 0.27 15 Rivas-Castillo et al., 2019

[i] a- Not Determined.

Conclusions

Technological approaches for the biotreatment of spent catalysts and metal uptake are tending to move from effective chemical and thermal processes to eco-friendly solutions that may be slower, but as effective as the first, or even more effective. The development of cleaner technologies based on biotechnological approaches is becoming increasingly important for the recycling of these materials and for waste minimization, since the controlled microbiological processing of high metal content residues present meaningful advantages besides its ecological nature, as low economical investment and maintainance, and low energy costs. There are already examples of biotechnological approaches successfully implemented at an industrial scale and, hopefully, they will be continuously installed in developing countries in the near future, as these eco-friendly and cheaper procedures may represent clear advantages in countries like Mexico.

The current challenge may be to optimize the leaching rates and metal recoveries with respect to the biotreatment parameters and to the microorganisms used. In this latter respect, one way can be to improve the microbial adaptations to spent catalysts, in order to enhance their resistance and metal removal capabilities; and other, to identify and improve new strains with these metal removal inherent abilities, including the identification and genetic manipulation of molecular targets crucial for metal uptake, which has been scarcely studied for most of the microorganisms that have been tested and identified with relevant potential for the biotreatment of spent catalysts. Besides, detailed analyses about the correlation between the presence and quantity of each metal in spent catalysts, and the affinity of each microorganism for the removal of metal targets, may be of significant importance to optimize the strategies and encourage the scale-up of these processes.

Acknowledgements

We deeply thank Prof. Gilberto José López de la Mora, Coordinator of the Scientific Illustration Development Program of the Universidad Tecnológica de la Zona Metropolitana del Valle de México, for his valuable assistance in the elaboration of the illustration regarding the mechanisms of metal bio-removal by microorganisms (Figure 1).

References

1 

Acevedo, F. (2002). Present and future of bioleaching in developing countries. Electronic Journal of Biotechnology, 5, 1-4. DOI:10.2225/vol5-issue2-fulltext-10.

F. Acevedo 2002Present and future of bioleaching in developing countriesElectronic Journal of Biotechnology51410.2225/vol5-issue2-fulltext-10

2 

Acevedo, F., Gentina, J. C. & Bustos, S. (1993). Bioleaching of minerals - a valid alternative for developing countries. Journal of Biotechnology, 31, 115-123. DOI:10.1016/0168-1656(93)90141-9

F. Acevedo J. C. Gentina S. Bustos 1993Bioleaching of minerals - a valid alternative for developing countriesJournal of Biotechnology3111512310.1016/0168-1656(93)90141-9

3 

Acharya, R. (1990). Bacterial leaching: A potential for developing countries. Genetic Engineering and Biotechnology Monitor, 27, 57-59.

R. Acharya 1990Bacterial leaching: A potential for developing countriesGenetic Engineering and Biotechnology Monitor275759

4 

Akcil, A., Vegliò, F., Ferella, F., Okudan, M. D. & Tuncuk, A. (2015). A review of metal recovery from spent petroleum catalysts and ash. Waste Management, 45, 420-433. DOI:10.1016/j.wasman.2015.07.007.

A. Akcil F. Vegliò F. Ferella M. D. Okudan A. Tuncuk 2015A review of metal recovery from spent petroleum catalysts and ashWaste Management4542043310.1016/j.wasman.2015.07.007

5 

Amiri, F., Yaghmaei, S. & Mousavi, S. M. (2011). Bioleaching of tungsten-rich spent hydrocracking catalyst using Penicillium simplicissimum. Bioresource Technology, 102, 1567-1573. DOI:10.1016/j.biortech.2010.08.087.

F. Amiri S. Yaghmaei S. M. Mousavi 2011Bioleaching of tungsten-rich spent hydrocracking catalyst using Penicillium simplicissimumBioresource Technology1021567157310.1016/j.biortech.2010.08.087

6 

Amiri, F., Mousavi, S. M., Yaghmaei, S. & Barati, M. (2012). Bioleaching kinetics of a spent refinery catalyst using Aspergillus niger at optimal conditions. Biochemical Engineering Journal, 67, 208-217. DOI:10.1016/j.bej.2012.06.011.

F. Amiri S. M. Mousavi S. Yaghmaei M. Barati 2012Bioleaching kinetics of a spent refinery catalyst using Aspergillus niger at optimal conditionsBiochemical Engineering Journal6720821710.1016/j.bej.2012.06.011

7 

Arenas-Isaac, G., Gómez-Ramírez, M., Montero-Álvarez, L. A., Tobón-Avilés, A., Fierros-Romero, G. & Rojas-Avelizapa, N. G. (2017). Novel microorganisms for the treatment of Ni and V as spent catalysts. Indian Journal of Biotechnology , 16, 370-379.

G. Arenas-Isaac M. Gómez-Ramírez L. A. Montero-Álvarez A. Tobón-Avilés G. Fierros-Romero N. G. Rojas-Avelizapa 2017Novel microorganisms for the treatment of Ni and V as spent catalystsIndian Journal of Biotechnology16370379

8 

Asghari, I., Mousavi, S. M., Amiri, F., & Tavassoli, S. (2013). Bioleaching of spent refinery catalysts: A review. Journal of Industrial and Engineering Chemistry, 19, 1069-1081. DOI:10.1016/j.jiec.2012.12.005

I. Asghari S. M. Mousavi F. Amiri S. Tavassoli 2013Bioleaching of spent refinery catalysts: A reviewJournal of Industrial and Engineering Chemistry191069108110.1016/j.jiec.2012.12.005

9 

Aung, K. M. M. & Ting, Y. P. (2005). Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus niger. Journal of Biotechnology , 116, 159-170. DOI:10.1016/j.jbiotec.2004.10.008.

K. M. M. Aung Y. P. Ting 2005Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus nigerJournal of Biotechnology11615917010.1016/j.jbiotec.2004.10.008

10 

Beolchini, F., Fonti, V., Ferella, F. & Vegliò, F. (2010a). Metal recovery from spent refinery catalysts by means of biotechnological strategies. Journal of Hazardous Materials, 178, 529-534. DOI:10.1016/j.jhazmat.2010.01.114.

F. Beolchini V. Fonti F. Ferella F. Vegliò 2010aMetal recovery from spent refinery catalysts by means of biotechnological strategiesJournal of Hazardous Materials17852953410.1016/j.jhazmat.2010.01.114

11 

Beolchini, F., Rocchetti, L., Regoli, F. & Dell’Anno, A. (2010b). Bioremediation of marine sediments contaminated by hydrocarbons: experimental analysis and kinetic modeling. Journal of Hazardous Materials , 182, 403-407. DOI:10.1016/j.jhazmat.2010.06.047.

F. Beolchini L. Rocchetti F. Regoli A. Dell’Anno 2010Bioremediation of marine sediments contaminated by hydrocarbons: experimental analysis and kinetic modelingJournal of Hazardous Materials18240340710.1016/j.jhazmat.2010.06.047

12 

Beolchini, F., Fonti, V., Dell’Anno, A., Rocchetti, L. & Vegliò, F. (2012). Assessment of biotechnological strategies for the valorization of metal bearing wastes. Waste Management , 32, 949-956. DOI:10.1016/j.wasman.2011.10.014.

F. Beolchini V. Fonti A. Dell’Anno L. Rocchetti F. Vegliò 2012Assessment of biotechnological strategies for the valorization of metal bearing wastesWaste Management3294995610.1016/j.wasman.2011.10.014

13 

Bharadwaj, A. & Ting, Y. P. (2013). Bioleaching of spent hydrotreating catalyst by acidophilic thermophile Acidianus brierleyi: Leaching mechanism and effect of decoking. Bioresource Technology , 130, 673-680. DOI:10.1016/j.biortech.2012.12.047.

A. Bharadwaj Y. P. Ting 2013Bioleaching of spent hydrotreating catalyst by acidophilic thermophile Acidianus brierleyi: Leaching mechanism and effect of decokingBioresource Technology13067368010.1016/j.biortech.2012.12.047

14 

Bitemirova, A. E., Alihanova, H. B., Spabekova, R. S., Shagrayeva, B. B. & Ermahanov, M. N. (2015). Regeneration of spent catalysts for furfural decarbonylation. Modern Applied Science, 9, 358-366. DOI:10.5539/mas.v9n5p358.

A. E. Bitemirova H. B. Alihanova R. S. Spabekova B. B. Shagrayeva M. N. Ermahanov 2015Regeneration of spent catalysts for furfural decarbonylationModern Applied Science935836610.5539/mas.v9n5p358

15 

Bosshard, P. P., Bachofen, R. & Brandl, H. (1996). Metal leaching of fly ash from municipal waste incineration by Aspergillus niger. Environmental Science and Technology, 30, 3066-3070. DOI:10.1021/es960151v.

P. P. Bosshard R. Bachofen H. Brandl 1996Metal leaching of fly ash from municipal waste incineration by Aspergillus nigerEnvironmental Science and Technology303066307010.1021/es960151v

16 

Brandl, H., Bosshard, R. & Wegmann, M. (2001). Computer-munching microbes: metal leaching from electronic scrap by bacteria and fungi. Hydrometallurgy, 59, 319-326. DOI:10.1016/S0304-386X(00)00188-2.

H. Brandl R. Bosshard M. Wegmann 2001Computer-munching microbes: metal leaching from electronic scrap by bacteria and fungiHydrometallurgy5931932610.1016/S0304-386X(00)00188-2

17 

Brandl, H., Lehmann, S., Faramarzi, M. A. & Martinelli, D. (2008). Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms. Hydrometallurgy , 94, 14-17. DOI:10.1016/j.hydromet.2008.05.016.

H. Brandl S. Lehmann M. A. Faramarzi D. Martinelli 2008Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganismsHydrometallurgy94141710.1016/j.hydromet.2008.05.016

18 

Bredberg, K., Karlsson, H. T. & Holst, O. (2004). Reduction of vanadium (V) with Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. Bioresource Technology , 92, 93-96. DOI:10.1016/j.biortech.2003.08.004.

K. Bredberg H. T. Karlsson O. Holst 2004Reduction of vanadium (V) with Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidansBioresource Technology92939610.1016/j.biortech.2003.08.004

19 

Brierley, C.L. (2008). How will biomining be applied in future? Transactions of Nonferrous Metals Society of China, 18, 1302-1310. DOI:10.1016/S1003-6326(09)60002-9.

C.L. Brierley 2008How will biomining be applied in future?Transactions of Nonferrous Metals Society of China181302131010.1016/S1003-6326(09)60002-9

20 

Brombacher, C., Bachofen, R. & Brandl, H. (1997). Biohydrometallurgical processing of solids: A patent review. Applied Microbiology and Biotechnology, 48, 577-587. DOI:10.1007/s002530051099.

C. Brombacher R. Bachofen H. Brandl 1997Biohydrometallurgical processing of solids: A patent reviewApplied Microbiology and Biotechnology4857758710.1007/s002530051099

21 

Burgstaller, W. & Schinner, F. (1993). Leaching of metals with fungi. Journal of Biotechnology , 27, 91-116. DOI:10.1016/0168-1656(93)90101-R.

W. Burgstaller F. Schinner 1993Leaching of metals with fungiJournal of Biotechnology279111610.1016/0168-1656(93)90101-R

22 

Cerruti, C., Curutchet, G. & Donati, E. (1998). Bio-dissolution of spent nickel-cadmium batteries using Thiobacillus ferrooxidans. Journal of Biotechnology , 62, 209-219. DOI:10.1016/S0168-1656(98)00065-0.

C. Cerruti G. Curutchet E. Donati 1998Bio-dissolution of spent nickel-cadmium batteries using Thiobacillus ferrooxidansJournal of Biotechnology6220921910.1016/S0168-1656(98)00065-0

23 

Chartier, M. & Couillard, D. (1997). Biological processess: the effects of initial pH, percentage inoculum and nutrient enrichment on the solubilization of sediment bound metals. Water, Air, and Soil Pollution, 96, 249-267. DOI:10.1023/A:1026472821060.

M. Chartier D. Couillard 1997Biological processess: the effects of initial pH, percentage inoculum and nutrient enrichment on the solubilization of sediment bound metalsWater, Air, and Soil Pollution9624926710.1023/A:1026472821060

24 

Chen, S.Y. & Lin, J. G. (2004). Bioleaching of heavy metals from contaminated sediment by indigenous sulfur-oxidizing bacteria in an air-lift bioreactor: Effects of sulfur concentration. Water Research, 38, 3205-3214. DOI:10.1016/j.watres.2004.04.050.

S.Y. Chen J. G. Lin 2004Bioleaching of heavy metals from contaminated sediment by indigenous sulfur-oxidizing bacteria in an air-lift bioreactor: Effects of sulfur concentrationWater Research383205321410.1016/j.watres.2004.04.050

25 

Chiranjeevi, T., Pragya, R., Gupta, S., Gokak, D. T. & Bhargava, S. (2016). Minimization of waste spent catalyst in refineries. Procedia Environmental Sciences, 35, 610-617. DOI:10.1016/j.proenv.2016.07.047

T. Chiranjeevi R. Pragya S. Gupta D. T. Gokak S. Bhargava 2016Minimization of waste spent catalyst in refineriesProcedia Environmental Sciences3561061710.1016/j.proenv.2016.07.047

26 

Choi, K. H., Kunisada, N., Korai, Y., Mochida, I. & Nakano, K. (2003). Facile ultra-deep desulfurization of gas oil through two-stage or -layer catalyst bed. Catalysis Today, 86, 277-286. DOI:10.1016/S0920-5861(03)00413-9.

K. H. Choi N. Kunisada Y. Korai I. Mochida K. Nakano 2003Facile ultra-deep desulfurization of gas oil through two-stage or -layer catalyst bedCatalysis Today8627728610.1016/S0920-5861(03)00413-9

27 

DaSilva, E. J. (1981). The renaissance of biotechnology: Man, microbe, biomass and industry. Acta Biotechnologica, 1, 207-246. DOI:10.1002/abio.370010302.

E. J. DaSilva 1981The renaissance of biotechnology: Man, microbe, biomass and industryActa Biotechnologica120724610.1002/abio.370010302

28 

Deveci, H., Akcil, A. & Alp, I. (2004). Bioleaching of complex zinc sulphides using mesophilic and thermophilic bacteria: Comparative importance of pH and iron. Hydrometallurgy , 73, 293-303. DOI:10.1016/j.hydromet.2003.12.001.

H. Deveci A. Akcil I. Alp 2004Bioleaching of complex zinc sulphides using mesophilic and thermophilic bacteria: Comparative importance of pH and ironHydrometallurgy7329330310.1016/j.hydromet.2003.12.001

29 

Dronawat, S. N., Svihla, C. K. & Hanley, T. R. (1995). The effects of agitation and aeration on the production of gluconic acid by Aspergillus niger. Applied Biochemistry and Biotechnology, 51-52, 347-354. DOI:10.1007/BF02933438.

S. N. Dronawat C. K. Svihla T. R. Hanley 1995The effects of agitation and aeration on the production of gluconic acid by Aspergillus nigerApplied Biochemistry and Biotechnology51-5234735410.1007/BF02933438

30 

Eijsbouts, S., Battiston, A. & van Leerdam, G. C. (2008). Life cycle of hydroprocessing catalysts and total catalyst management. Catalysis Today , 130, 361-373. DOI:10.1016/j.cattod.2007.10.112

S. Eijsbouts A. Battiston G. C. van Leerdam 2008Life cycle of hydroprocessing catalysts and total catalyst managementCatalysis Today13036137310.1016/j.cattod.2007.10.112

31 

Fan, J., Onal Okyay, T. & Rodrigues, D. (2014). The synergism of temperature, pH and growth phases on heavy metal biosorption by two environmental isolates. Journal of Hazardous Materials , 279, 236-243. DOI:10.1016/j.jhazmat.2014.07.016.

J. Fan T. Onal Okyay D. Rodrigues 2014The synergism of temperature, pH and growth phases on heavy metal biosorption by two environmental isolatesJournal of Hazardous Materials27923624310.1016/j.jhazmat.2014.07.016

32 

Faramarzi, M. A., Stagars, M., Pensini, E., Krebs, W. & Brandl, H. (2004). Metal solubilization from metal-containing solid materials by cyanogenic Chromobacterium violaceum. Journal of Biotechnology , 113, 321-326. DOI:10.1016/j.jbiotec.2004.03.031.

M. A. Faramarzi M. Stagars E. Pensini W. Krebs H. Brandl 2004Metal solubilization from metal-containing solid materials by cyanogenic Chromobacterium violaceumJournal of Biotechnology11332132610.1016/j.jbiotec.2004.03.031

33 

Faramarzi, M. A. & Brandl, H. (2006). Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicida. FEMS Microbiology letters, 259, 47-52. DOI:10.1111/j.1574-6968.2006.00245.x.

M. A. Faramarzi H. Brandl 2006Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicidaFEMS Microbiology letters259475210.1111/j.1574-6968.2006.00245.x

34 

Ferreira, P. F., Sérvulo, E. F. C., Ferreira, D. M. & Oliveira, F. J. S. (2016). Assessment of metal recovery from raw spent hydrodesulfurization catalyst through bioleaching and chemical leaching. Brazilian Journal of Petroleum and Gas, 9, 137-145. DOI:10.5419/bjpg2015-0014.

P. F. Ferreira E. F. C. Sérvulo D. M. Ferreira F. J. S. Oliveira 2016Assessment of metal recovery from raw spent hydrodesulfurization catalyst through bioleaching and chemical leachingBrazilian Journal of Petroleum and Gas913714510.5419/bjpg2015-0014

35 

Gadd, G. M. (2004). Microbial influence on metal mobility and application for bioremediation. Geoderma, 122, 109-119. DOI:10.1016/j.geoderma.2004.01.002.

G. M. Gadd 2004Microbial influence on metal mobility and application for bioremediationGeoderma12210911910.1016/j.geoderma.2004.01.002

36 

Garza-González, M. T., Barboza-Pérez, D., Vázquez-Rodríguez, A., García-Gutiérrez, D. I., Zarate, X., Cantú-Cárdenas, M. E. & Cárdenas, M. C. (2016). Correction: metal-induced production of a novel bioadsorbent exopolysaccharide in a native Rhodotorula mucilaginosa from the Mexican northeastern region. PLOS ONE, 11, e0150522. DOI:10.1371/journal.pone.0150522.

M. T. Garza-González D. Barboza-Pérez A. Vázquez-Rodríguez D. I. García-Gutiérrez X. Zarate M. E. Cantú-Cárdenas M. C. Cárdenas 2016Correction: metal-induced production of a novel bioadsorbent exopolysaccharide in a native Rhodotorula mucilaginosa from the Mexican northeastern regionPLOS ONE11e015052210.1371/journal.pone.0150522

37 

Gentina, J. C., & Acevedo, F. (1985). Microbial ore leaching in developing countries. Trends in Biotechnology, 3, 86-89. DOI:10.1016/0167-7799(85)90087-3.

J. C. Gentina F. Acevedo 1985Microbial ore leaching in developing countriesTrends in Biotechnology3868910.1016/0167-7799(85)90087-3

38 

Gerayeli, F., Ghojavand, F., Mousavi, S.M., Yaghmaei, S. & Amiri, F. (2013). Screening and optimization of effective parameters in biological extraction of heavy metals from refinery spent catalysts using a thermophilic bacterium. Separation and Purification Technology, 118, 151-161. DOI:10.1016/j.seppur.2013.06.033.

F. Gerayeli F. Ghojavand S.M. Mousavi S. Yaghmaei F. Amiri 2013Screening and optimization of effective parameters in biological extraction of heavy metals from refinery spent catalysts using a thermophilic bacteriumSeparation and Purification Technology11815116110.1016/j.seppur.2013.06.033

39 

Gholami, R. M., Borghei, S. M. & Mousavi, S. M. (2011). Bacterial leaching of a spent Mo-Co-Ni refinery catalyst using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. Hydrometallurgy , 106, 26-31. DOI:10.1016/j.hydromet.2010.11.011.

R. M. Gholami S. M. Borghei S. M. Mousavi 2011Bacterial leaching of a spent Mo-Co-Ni refinery catalyst using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidansHydrometallurgy106263110.1016/j.hydromet.2010.11.011

40 

Gholami, R. M., Razeghi, N. & Ghasemi, S. (2015). Bio-separation of heavy metals from spent catalysts using Acidithiobacillus thiooxidans. Journal of Scientific Research and Development, 2, 53-56.

R. M. Gholami N. Razeghi S. Ghasemi 2015Bio-separation of heavy metals from spent catalysts using Acidithiobacillus thiooxidansJournal of Scientific Research and Development25356

41 

Gómez-Ramírez, M., Flores-Martínez, Y. A., López-Hernández, L. J. & Rojas-Avelizapa, N. G. (2014). Effect of Fe2+ concentration on microbial removal of Ni and V from spent catalyst. Journal of Chemical, Biological and Physical Sciences Section B: Environmental Biotechnology, 4, 101-109.

M. Gómez-Ramírez Y. A. Flores-Martínez L. J. López-Hernández N. G. Rojas-Avelizapa 2014Effect of Fe2+ concentration on microbial removal of Ni and V from spent catalystJournal of Chemical, Biological and Physical Sciences Section B: Environmental Biotechnology4101109

42 

Gómez-Ramírez, M., Montero-Álvarez, L. A., Tobón-Avilés, A., Fierros-Romero, G., & Rojas-Avelizapa, N. G. (2015a). Microbacterium oxydans and Microbacterium liquefaciens: A biological alternative for the treatment of Ni-V-containing wastes. Journal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering, 50, 37-41. DOI:10.1080/10934529.2015.994953.

M. Gómez-Ramírez L. A. Montero-Álvarez A. Tobón-Avilés G. Fierros-Romero N. G. Rojas-Avelizapa 2015Microbacterium oxydans and Microbacterium liquefaciens: A biological alternative for the treatment of Ni-V-containing wastesJournal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering50374110.1080/10934529.2015.994953

43 

Gómez-Ramírez, M., Plata-González, A., Fierros-Romero, G. & Rojas-Avelizapa, N. G. (2015b). Novel filamentous fungi for metal removal from spent catalyst. Advanced Materials Research, 1130, 673-676. DOI:10.4028/www.scientific.net/AMR.1130.673.

M. Gómez-Ramírez A. Plata-González G. Fierros-Romero N. G. Rojas-Avelizapa 2015Novel filamentous fungi for metal removal from spent catalystAdvanced Materials Research113067367610.4028/www.scientific.net/AMR.1130.673

44 

Grewal, H. S. & Kalra, K. L. (1995). Fungal production of citric acid. Biotechnology Advances, 13, 209-234. DOI:10.1016/0734-9750(95)00002-8.

H. S. Grewal K. L. Kalra 1995Fungal production of citric acidBiotechnology Advances1320923410.1016/0734-9750(95)00002-8

45 

Groudev, S. N., Spasova, I., Georgiev, P., & Nicolova, M. (2014). High quality kaolin produced by microbial treatment. Annual of the University of Mining and Geology, Sofia, Part II, 57, 115-119.

S. N. Groudev I. Spasova P. Georgiev M. Nicolova 2014High quality kaolin produced by microbial treatmentAnnual of the University of Mining and Geology, SofiaII57115119

46 

Hong, Y. & Valix, M. (2014). Bioleaching of electronic waste using acidophilic sulfur oxidising bacteria. Journal of Cleaner Production, 65, 465-472. DOI:10.1016/j.jclepro.2013.08.043.

Y. Hong M. Valix 2014Bioleaching of electronic waste using acidophilic sulfur oxidising bacteriaJournal of Cleaner Production6546547210.1016/j.jclepro.2013.08.043

47 

Islam, E. & Sar, P. (2016). Diversity, metal resistance and uranium sequestration abilities of bacteria from uranium ore deposit in deep earth stratum. Ecotoxicology and Environmental Safety, 127, 12-21. DOI:10.1016/j.ecoenv.2016.01.001.

E. Islam P. Sar 2016Diversity, metal resistance and uranium sequestration abilities of bacteria from uranium ore deposit in deep earth stratumEcotoxicology and Environmental Safety127122110.1016/j.ecoenv.2016.01.001

48 

Johnson, D. B. (2013). Development and application of biotechnologies in the metal mining industry. Environmental Science and Pollution Research International, 20, 7768-7776. DOI: 10.1007/s11356-013-1482-7.

D. B. Johnson 2013Development and application of biotechnologies in the metal mining industryEnvironmental Science and Pollution Research International207768777610.1007/s11356-013-1482-7

49 

Jong, W., Rhoads, S., Stubbs, A. & Stoelting, T. (1992). Recovery of principal metal values from waste hydroprocessing catalysts. Washington: US Bureau of Mines, US Department of Interior RI 9252.

W. Jong S. Rhoads A. Stubbs T. Stoelting 1992Recovery of principal metal values from waste hydroprocessing catalystsWashingtonUS Bureau of MinesUS Department of Interior RI 9252

50 

Kaushik, P., Rawat, N., Mathur, M., Raghuvanshi, P., Bhatnagar, P., Swarnkar, H. & Flora, S. (2012). Arsenic hyper-tolerance in four Microbacterium species isolated from soil contaminated with textile effluent. Toxicology International, 19, 188-94. DOI: 10.4103/0971-6580.97221.

P. Kaushik N. Rawat M. Mathur P. Raghuvanshi P. Bhatnagar H. Swarnkar S. Flora 2012Arsenic hyper-tolerance in four Microbacterium species isolated from soil contaminated with textile effluentToxicology International1918819410.4103/0971-6580.97221.

51 

Kim, D. J., Mishra, D., Park, K. H., Ahn, J. G. & Ralph, D. E. (2008). Metal leaching from spent petroleum catalyst by acidophilic bacteria in presence of pyrite. Materials Transactions, 49, 2383-2388. DOI: 10.2320/matertrans.MER2008187.

D. J. Kim D. Mishra K. H. Park J. G. Ahn D. E. Ralph 2008Metal leaching from spent petroleum catalyst by acidophilic bacteria in presence of pyriteterials Transactions492383238810.2320/matertrans.MER2008187.

52 

Kim, S. C., & Shim, W. G. (2008a). Influence of physicochemical treatments on iron-based spent catalyst for catalytic oxidation of toluene. Journal of Hazardous Materials , 154, 310-316. DOI: 10.1016/j.jhazmat.2007.10.027.

S. C. Kim W. G. Shim 2008Influence of physicochemical treatments on iron-based spent catalyst for catalytic oxidation of tolueneJournal of Hazardous Materials15431031610.1016/j.jhazmat.2007.10.027.

53 

Kim, S. C. & Shim, W. G. (2008b). Recycling the copper based spent catalyst for catalytic combustion of VOCs. Applied Catalysis B: Environmental, 79, 149-156. DOI: 10.1016/j.apcatb.2007.10.016.

S. C. Kim W. G. Shim 2008Recycling the copper based spent catalyst for catalytic combustion of VOCsApplied Catalysis B: Environmental7914915610.1016/j.apcatb.2007.10.016.

54 

Konishi, Y., Tokushige, M., Asai, S. & Suzuki, T. (2001). Copper recovery from chalcopyrite concentrate by acidophilic thermophile Acidianus brierleyi in batch and continuous-flow stirred tank reactors. Hydrometallurgy , 59, 271-282. DOI: 10.1016/S0304-386X(00)00173-0.

Y. Konishi M. Tokushige S. Asai T. Suzuki 2001Copper recovery from chalcopyrite concentrate by acidophilic thermophile Acidianus brierleyi in batch and continuous-flow stirred tank reactorsHydrometallurgy5927128210.1016/S0304-386X(00)00173-0.

55 

Krebs, W., Brombacher, C., Bosshard, P. P., Bachofen, R. & Brandl, H. (1997). Microbial recovery of metals from solids. FEMS Microbiology Reviews, 20, 605-617. DOI: 10.1016/S0168-6445(97)00037-5.

W. Krebs C. Brombacher P. P. Bosshard R. Bachofen H. Brandl 1997Microbial recovery of metals from solidsFEMS Microbiology Reviews2060561710.1016/S0168-6445(97)00037-5.

56 

Lee, J. & Pandey, B. D. (2012). Bio-processing of solid wastes and secondary resources for metal extraction-A review. Waste Management , 32, 3-18. DOI: 10.1016/j.wasman.2011.08.010.

J. Lee B. D. Pandey 2012Bio-processing of solid wastes and secondary resources for metal extraction-A reviewWaste Management3231810.1016/j.wasman.2011.08.010.

57 

Liles, A.W. & Schwartz, R. D. (1976). Method of treating waste water. US patent 3,968,036.

A.W. Liles R. D. Schwartz 1976Method of treating waste waterUS patent 3,968,036

58 

Liu, C., Yu, Y. & Zhao, H. (2005). Hydrodenitrogenation of quinoline over Ni-Mo/Al2O3 catalyst modified with fluorine and phosphorus. Fuel Processing Technology, 86, 449-460. DOI: 10.1016/j.fuproc.2004.05.002.

C. Liu Y. Yu H. Zhao 2005Hydrodenitrogenation of quinoline over Ni-Mo/Al2O3 catalyst modified with fluorine and phosphorusFuel Processing Technology8644946010.1016/j.fuproc.2004.05.002.

59 

Liu, Y. G., Zhou, M., Zeng, G. M., Wang, X., Li, X., Fan, T., & Xu, W. H. (2008). Bioleaching of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria: effects of substrate concentration. Bioresource Technology , 99, 4124-4129. DOI: 10.1016/j.biortech.2007.08.064.

Y. G. Liu M. Zhou G. M. Zeng X. Wang X. Li T. Fan W. H. Xu 2008Bioleaching of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria: effects of substrate concentrationBioresource Technology994124412910.1016/j.biortech.2007.08.064.

60 

Llanos, Z. R. & Lacave, J. D.W. (1986). Treatment of spent hydroprocessing catalysts at Gulf Chemical and Metallurgical Corporation. In SME Annual Meeting. (Preprint No. 86-43). Louisiana, March 2-6.

Z. R. Llanos J. D.W. Lacave 1986Treatment of spent hydroprocessing catalysts at Gulf Chemical and Metallurgical Corporation. In SME Annual Meeting86-43Louisiana

61 

Luque-Almagro, V. M., Moreno-Vivián, C. & Roldán, M. D. (2016). Biodegradation of cyanide wastes from mining and jewellery industries. Current Opinion in Biotechnology, 38, 9-13. DOI: 10.1016/j.copbio.2015.12.004.

V. M. Luque-Almagro C. Moreno-Vivián M. D. Roldán 2016Biodegradation of cyanide wastes from mining and jewellery industriesCurrent Opinion in Biotechnology3891310.1016/j.copbio.2015.12.004.

62 

Marafi, M. & Stanislaus, A. (2007). Studies on recycling and utilization of spent catalysts: Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalysts. Applied Catalysis B: Environment, 71, 199-206. DOI: 10.1016/j.apcatb.2006.09.005.

M. Marafi A. Stanislaus 2007Studies on recycling and utilization of spent catalysts: Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalystsApplied Catalysis B: Environment7119920610.1016/j.apcatb.2006.09.005.

63 

Marafi, M. & Stanislaus, A. (2008a). Spent catalyst waste management: A review: Part I-Developments in hydroprocessing catalyst waste reduction and use. Resources, Conservationand Recycling, 52, 859-873. DOI: 10.1016/j.resconrec.2008.02.004.

M. Marafi A. Stanislaus 2008Spent catalyst waste management: A review: Part I-Developments in hydroprocessing catalyst waste reduction and useResources, Conservationand Recycling5285987310.1016/j.resconrec.2008.02.004.

64 

Marafi, M. & Stanislaus, A. (2008b). Spent hydroprocessing catalyst management: A review: Part II. Advances in metal recovery and safe disposal methods. Resources, Conservation and Recycling, 53, 1-26. DOI: 10.1016/j.resconrec.2008.08.005.

M. Marafi A. Stanislaus 2008Spent hydroprocessing catalyst management: A review: Part II. Advances in metal recovery and safe disposal methodsResources, Conservation and Recycling5312610.1016/j.resconrec.2008.08.005.

65 

Marafi, M., Stanislaus, A. & Furimsky, E. (2010). Handbook of spent hydroprocessing catalysts regeneration, rejuvenation and reclamation. London: Elsevier.

M. Marafi A. Stanislaus E. Furimsky 2010Handbook of spent hydroprocessing catalysts regeneration, rejuvenation and reclamationLondonElsevier

66 

Mishra, D., Kim, D. J., Ralph, D. E., Ahn, J. G. & Rhee, Y. H. (2007). Bioleaching of vanadium rich spent refinery catalysts using sulfur oxidizing lithotrophs. Hydrometallurgy , 88, 202-209. DOI: 10.1016/j.hydromet.2007.05.007.

D. Mishra D. J. Kim D. E. Ralph J. G. Ahn Y. H. Rhee 2007Bioleaching of vanadium rich spent refinery catalysts using sulfur oxidizing lithotrophsHydrometallurgy8820220910.1016/j.hydromet.2007.05.007.

67 

Mishra, D., Kim, D. J., Ralph, D. E., Ahn, J. G. & Rhee, Y. H. (2008). Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect. Journal of Hazardous Materials , 152, 1082-1091. DOI: 10.1016/j.jhazmat.2007.07.083.

D. Mishra D. J. Kim D. E. Ralph J. G. Ahn Y. H. Rhee 2008Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspectJournal of Hazardous Materials1521082109110.1016/j.jhazmat.2007.07.083.

68 

Mishra, D. & Rhee, Y. H. (2014). Microbial leaching of metals from solid industrial wastes. Journal of Microbiology, 52, 1-7. DOI: 10.1007/s12275-014-3532-3.

D. Mishra Y. H. Rhee 2014Microbial leaching of metals from solid industrial wastesJournal of Microbiology521-710.1007/s12275-014-3532-3.

69 

Motaghed, M., Mousavi, S. M., Rastegar, S. O. & Shojaosadati, S. A. (2014). Platinum and rhenium extraction from a spent refinery catalyst using Bacillus megaterium as a cyanogenic bacterium: Statistical modeling and process optimization. Bioresource Technology , 171, 401-409. DOI: 10.1016/j.biortech.2014.08.032.

M. Motaghed S. M. Mousavi S. O. Rastegar S. A. Shojaosadati 2014Platinum and rhenium extraction from a spent refinery catalyst using Bacillus megaterium as a cyanogenic bacterium: Statistical modeling and process optimizationBioresource Technology17140140910.1016/j.biortech.2014.08.032.

70 

Noori Felegari, Z., Nematdoust Haghi, B., Amoabediny, G., Mousavi, S. M. & Amouei Torkmahalleh, M. (2014). An optimized integrated process for the bioleaching of a spent refinery processing catalysts. International Journal of Environmental Research, 8, 621-634.

Z. Noori Felegari B. Nematdoust Haghi G. Amoabediny S. M. Mousavi M. Amouei Torkmahalleh 2014An optimized integrated process for the bioleaching of a spent refinery processing catalystsInternational Journal of Environmental Research8621634

71 

Olson, G. J., Brierley, J. A. & Brierley, C. L. (2003). Bioleaching review part B: Progress in bioleaching: applications of microbial processes by the minerals industries. Applied Microbiology and Biotechnology , 63, 249-257. DOI: 10.1007/s00253-003-1404-6.

G. J. Olson J. A. Brierley C. L. Brierley 2003Bioleaching review part B: Progress in bioleaching: applications of microbial processes by the minerals industriesApplied Microbiology and Biotechnology6324925710.1007/s00253-003-1404-6.

72 

Pathak, A., Srichandan, H. & Kim, D. (2015). Feasibility of bioleaching in removing metals (Al, Ni, V and Mo) from as received raw petroleum spent refinery catalyst: A comparative study on leaching yields, risk assessment code and reduced partition index. Materials Transactions , 56, 1278-1286. DOI: 10.2320/matertrans.M2015104.

A. Pathak H. Srichandan D. Kim 2015Feasibility of bioleaching in removing metals (Al, Ni, V and Mo) from as received raw petroleum spent refinery catalyst: A comparative study on leaching yields, risk assessment code and reduced partition indexMaterials Transactions561278128610.2320/matertrans.M2015104.

73 

Pathak, A., Srichandan, H. & Kim, D. J. (2019). Column bioleaching of metals from refinery spent catalyst by Acidithiobacillus thiooxidans: Effect of operational modifications on metal extraction, metal precipitation, and bacterial attachment. Journal of Environmental Management, 242, 372-383. DOI: 10.1016/j.jenvman.2019.04.081.

A. Pathak H. Srichandan D. J. Kim 2019Column bioleaching of metals from refinery spent catalyst by Acidithiobacillus thiooxidans: Effect of operational modifications on metal extraction, metal precipitation, and bacterial attachmentJournal of Environmental Management24237238310.1016/j.jenvman.2019.04.081.

74 

Pradhan, D., Mishra, D., Kim, D. J., Chaudhury, G. R., & Lee, S.W. (2009). Dissolution kinetics of spent petroleum catalyst using two different acidophiles. Hydrometallurgy , 99, 157-162. DOI: 10.1016/j.hydromet.2009.07.014.

D. Pradhan D. Mishra D. J. Kim G. R. Chaudhury S.W. Lee 2009Dissolution kinetics of spent petroleum catalyst using two different acidophilesHydrometallurgy9915716210.1016/j.hydromet.2009.07.014.

75 

Pradhan, D., Mishra, D., Kim, D. J., Ahn, J. G., Chaudhury, G. R. & Lee, S. W. (2010). Bioleaching kinetics and multivariate analysis of spent petroleum catalyst dissolution using two acidophiles. Journal of Hazardous Materials , 175, 267-273. DOI: 10.1016/j.jhazmat.2009.09.159.

D. Pradhan D. Mishra D. J. Kim J. G. Ahn G. R. Chaudhury S. W. Lee 2010Bioleaching kinetics and multivariate analysis of spent petroleum catalyst dissolution using two acidophilesJournal of Hazardous Materials17526727310.1016/j.jhazmat.2009.09.159.

76 

Rawlings, D. E. (2002). Heavy metal mining using microbes. Annual Reviews of Microbiology, 56, 65-91. DOI: 10.1146/annurev.micro.56.012302.161052.

D. E. Rawlings 2002Heavy metal mining using microbesAnnual Reviews of Microbiology56659110.1146/annurev.micro.56.012302.161052

77 

Rivas-Castillo, A. M., Orona-Tamayo, D., Gómez-Ramírez, M. & Rojas-Avelizapa, N. G. (2017a). Diverse molecular resistance mechanisms of Bacillus megaterium during metal removal present in a spent catalyst. Biotechnology and Bioprocess Engineering, 22, 296-307. DOI: 10.1007/s12257-016-0019-6.

A. M. Rivas-Castillo D. Orona-Tamayo M. Gómez-Ramírez N. G. Rojas-Avelizapa 2017Diverse molecular resistance mechanisms of Bacillus megaterium during metal removal present in a spent catalystBiotechnology and Bioprocess Engineering2229630710.1007/s12257-016-0019-6.

78 

Rivas-Castillo, A. M., Monges-Rojas, T. L. & Rojas-Avelizapa, N. G. (2017b). Specificity of Mo and V removal from a spent catalyst by Cupriavidus metallidurans CH34. Waste and Biomass Valorization, 10, 1037-1042. DOI: 10.1007/s12649-017-0093-9.

A. M. Rivas-Castillo T. L. Monges-Rojas N. G. Rojas-Avelizapa 2017Specificity of Mo and V removal from a spent catalyst by Cupriavidus metallidurans CH34Waste and Biomass Valorization101037104210.1007/s12649-017-0093-9.

79 

Rivas-Castillo, A. M., Gómez-Ramírez, M., Rodríguez-Pozos, I. & Rojas-Avelizapa, N. G. (2018). Bioleaching of metals contained in spent catalysts by Acidithiobacillus thiooxidans DSM 26636. International Journal of Biotechnology and Bioengineering, 12, 430-434.

A. M. Rivas-Castillo M. Gómez-Ramírez I. Rodríguez-Pozos N. G. Rojas-Avelizapa 2018Bioleaching of metals contained in spent catalysts by Acidithiobacillus thiooxidans DSM 26636International Journal of Biotechnology and Bioengineering12430434

80 

Rivas-Castillo, A. M., Guatemala-Cisneros, M., Gómez-Ramírez, M. & Rojas-Avelizapa, N.G. (2019). Metal removal and morphological changes of B. megaterium in the presence of a spent catalyst. Journal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering , 54, 1-8. DOI: 10.1080/10934529.2019.1571307.

A. M. Rivas-Castillo M. Guatemala-Cisneros M. Gómez-Ramírez N.G. Rojas-Avelizapa 2019Metal removal and morphological changes of B. megaterium in the presence of a spent catalystJournal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering541-810.1080/10934529.2019.1571307.

81 

Rohwerder, T., Gehrke, T., Kinzler, K. & Sand, W. (2003). Bioleaching review part A: Progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation. Applied Microbiology and Biotechnology , 63, 239-248. DOI: 10.1007/s00253-003-1448-7.

T. Rohwerder T. Gehrke K. Kinzler W. Sand 2003Bioleaching review part A: Progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidationApplied Microbiology and Biotechnology6323924810.1007/s00253-003-1448-7.

82 

Rojas-Avelizapa, N. G., Gómez-Ramírez, M. & Alamilla-Martínez, D. G. (2015). Metal removal from spent catalyst using Microbacterium liquefaciens in solid culture. Advanced Materials Research , 1130, 564-567. DOI: 10.4028/www.scientific.net/AMR.1130.564.

N. G. Rojas-Avelizapa M. Gómez-Ramírez D. G. Alamilla-Martínez 2015Metal removal from spent catalyst using Microbacterium liquefaciens in solid cultureAdvanced Materials Research113056456710.4028/www.scientific.net/AMR.1130.564.

83 

Rui, Z., Wu, S., Ji, H. & Liu, Z. (2015). Reactivation and Reuse of Platinum-Based Spent Catalysts for Combustion of Exhaust Organic Gases. Chemical Engineering & Technology, 38, 409-415. DOI: 10.1002/ceat.201400467.

Z. Rui S. Wu H. Ji Z. Liu 2015Reactivation and Reuse of Platinum-Based Spent Catalysts for Combustion of Exhaust Organic GasesChemical Engineering & Technology3840941510.1002/ceat.201400467.

84 

Sahu, K. K., Agrawal, A., & Mishra, D. (2013). Hazardous waste to materials: recovery of molybdenum and vanadium from acidic leach liquor of spent hydroprocessing catalyst using alamine 308. Journal of Environmental Management , 125, 68-73. DOI: 10.1016/j.jenvman.2013.03.032.

K. K. Sahu A. Agrawal D. Mishra 2013Hazardous waste to materials: recovery of molybdenum and vanadium from acidic leach liquor of spent hydroprocessing catalyst using alamine 308Journal of Environmental Management125687310.1016/j.jenvman.2013.03.032.

85 

Sand, W., Gehrke, T., Jozsa, P. G. & Schippers, A. (2001). (Bio) chemistry of bacterial leaching-Direct vs. indirect bioleaching. Hydrometallurgy , 59, 159-175. DOI: 10.1016/S0304-386X(00)00180-8.

W. Sand T. Gehrke P. G. Jozsa A. Schippers 2001(Bio) chemistry of bacterial leaching-Direct vs. indirect bioleachingHydrometallurgy5915917510.1016/S0304-386X(00)00180-8.

86 

Sanga, S. & Nishimura, Y. (1976). Sewer waste water treating agent produced from waste cracking catalyst. US patent 3,960,760.

S. Sanga Y. Nishimura 1976Sewer waste water treating agent produced from waste cracking catalystUS patent 3,960,760

87 

Santhiya, D. & Ting, Y. P. (2005). Bioleaching of spent refinery processing catalyst using Aspergillus niger with high-yield oxalic acid. Journal of Biotechnology , 116, 171-184. DOI: 10.1016/j.jbiotec.2004.10.011.

D. Santhiya Y. P. Ting 2005Bioleaching of spent refinery processing catalyst using Aspergillus niger with high-yield oxalic acidJournal of Biotechnology11617118410.1016/j.jbiotec.2004.10.011

88 

Santhiya, D. & Ting, Y. P. (2006). Use of adapted Aspergillus niger in the bioleaching of spent refinery processing catalyst. Journal of Biotechnology , 121, 62-74. DOI: 10.1016/j.jbiotec.2005.07.002.

D. Santhiya Y. P. Ting 2006Use of adapted Aspergillus niger in the bioleaching of spent refinery processing catalystJournal of Biotechnology121627410.1016/j.jbiotec.2005.07.002.

89 

Sharma, M., Bisht, V., Singh, B., Jain, P., Mandal, A. K., Lal, B. & Sarma, P. M. (2015). Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM- 11478. Indian Journal of Experimental Biology, 53, 388-394.

M. Sharma V. Bisht B. Singh P. Jain A. K. Mandal B. Lal P. M. Sarma 2015Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM- 11478Indian Journal of Experimental Biology53388394

90 

Shim, W. G. & Kim, S. C. (2010). Heterogeneous adsorption and catalytic oxidation of benzene, toluene and xylene over spent and chemically regenerated platinum catalyst supported on activated carbon. Applied Surface Science, 256, 5566-5571. DOI: 10.1016/j.apsusc.2009.12.148.

W. G. Shim S. C. Kim 2010Heterogeneous adsorption and catalytic oxidation of benzene, toluene and xylene over spent and chemically regenerated platinum catalyst supported on activated carbonApplied Surface Science2565566557110.1016/j.apsusc.2009.12.148.

91 

Srichandan, H., Kim, D. J., Gahan, C. S. & Akcil, A. (2013). Microbial extraction metal values from spent catalyst: Mini review. In Thatoi, H.N. (Ed.). Advances in Biotechnology. (pp. 225-239) New Delhi: Indian Publisher.

H. Srichandan D. J. Kim C. S. Gahan A. Akcil 2013Microbial extraction metal values from spent catalyst: Mini review H.N. Thatoi Advances in Biotechnology225239New DelhiIndian Publisher

92 

Srichandan, H., Singh, S., Pathak, A., Kim, D. J., Lee, S.W. & Heyes, G. (2014). Bioleaching of metals from spent refinery petroleum catalyst using moderately thermophilic bacteria: Effect of particle size. Journal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering , 49, 807-818. DOI: 10.1080/10934529.2014.882211.

H. Srichandan S. Singh A. Pathak D. J. Kim S.W. Lee G. Heyes 2014Bioleaching of metals from spent refinery petroleum catalyst using moderately thermophilic bacteria: Effect of particle sizeJournal of Environmental Science and Health Part A. Toxic/Hazardous Substances and Environmental Engineering4980781810.1080/10934529.2014.882211.

93 

Stanislaus, A., Gouda, G. R. & Al-Fulaij, S. (1998). Safe disposal and utilization of heavy-metal containing spent catalysts by thermal treatment: Waste management and remediation in oil production, up grading and refining processes. Preprints - American Chemical Society, Division of Petroleum Chemistry, 43, 491-494.

A. Stanislaus G. R. Gouda S. Al-Fulaij 1998Safe disposal and utilization of heavy-metal containing spent catalysts by thermal treatment: Waste management and remediation in oil production, up grading and refining processesPreprints - American Chemical Society, Division of Petroleum Chemistry43491494

94 

Stanislaus, A., Marafi, A. & Rana, M. S. (2010). Recent advances in the science and technology of ultra low sulfur diesel (ULSD) production. Catalysis Today , 153, 1-68. DOI: 10.1016/j.cattod.2010.05.011.

A. Stanislaus A. Marafi M. S. Rana 2010Recent advances in the science and technology of ultra low sulfur diesel (ULSD) productionCatalysis Today15316810.1016/j.cattod.2010.05.011.

95 

Strasser, H., Burgstaller, W. & Schinner, F. (1994). High-yield production of oxalic acid for metal leaching processes by Aspergillus niger. FEMS Microbiology Letters, 119, 365-370. DOI: 10.1111/j.1574-6968.1994.tb06914.x.

H. Strasser W. Burgstaller F. Schinner 1994High-yield production of oxalic acid for metal leaching processes by Aspergillus nigerFEMS Microbiology Letters11936537010.1111/j.1574-6968.1994.tb06914.x.

96 

Su, N., Chen, Z. H. & Fang, H.Y. (2001). Reuse of spent catalyst as fine aggregate in cement mortar. Cement and Concrete Composites, 23, 111-118. DOI: 10.1016/S0958-9465(00)00074-3.

N. Su Z. H. Chen H.Y. Fang 2001Reuse of spent catalyst as fine aggregate in cement mortarCement and Concrete Composites2311111810.1016/S0958-9465(00)00074-3.

97 

Taha, R., Al-Kamyani, Z., Al-Jabri, K., Baawain, M. & Al-Shamsi, K. (2012). Recycling of waste spent catalyst in road construction and masonry blocks. Journal of Hazardous Materials , 229-230, 122-127. DOI: 10.1016/j.jhazmat.2012.05.083.

R. Taha Z. Al-Kamyani K. Al-Jabri M. Baawain K. Al-Shamsi 2012Recycling of waste spent catalyst in road construction and masonry blocksJournal of Hazardous Materials229-23012212710.1016/j.jhazmat.2012.05.083.

98 

Valix, M. & Loon, L. (2003). Adaptive tolerance behaviour of fungi in heavy metals. Minerals Engineering, 16, 193-198. DOI: 10.1016/S0892-6875(03)00004-9.

M. Valix L. Loon 2003Adaptive tolerance behaviour of fungi in heavy metalsMinerals Engineering1619319810.1016/S0892-6875(03)00004-9.

99 

Vargas, F., Restrepo, E., Rodríguez, J. E., Vargas, F., Arbeláez, L., Caballero, P., Arias, J., López, E., Latorre, G. & Duarte, G. (2018). Solid-state synthesis of mullite from spent catalysts for manufacturing refractory brick coatings. Ceramics International, 44, 3556-3562. DOI: 10.1016/j.ceramint.2017.11.044.

F. Vargas E. Restrepo J. E. Rodríguez F. Vargas L. Arbeláez P. Caballero J. Arias E. López G. Latorre G. Duarte 2018Solid-state synthesis of mullite from spent catalysts for manufacturing refractory brick coatingsCeramics International443556356210.1016/j.ceramint.2017.11.044.

100 

Villegas, L. B., Amoroso, M. J. & de Figueroa, L. I. C. (2005). Copper tolerant yeasts isolated from polluted area of Argentina. Journal of Basic Microbiology, 45, 381-391. DOI: 10.1002/jobm.200510569.

L. B. Villegas M. J. Amoroso L. I. C. de Figueroa 2005Copper tolerant yeasts isolated from polluted area of ArgentinaJournal of Basic Microbiology4538139110.1002/jobm.200510569.

101 

Warhurst, A. (1985). Biotechnology for mining: The potential of an emerging technology, the Andean Pact Copper Project and some policy implications. Development and Change, 16, 93-121. DOI:10.1111/j.1467-7660.1985.tb00203.x.

A. Warhurst 1985Biotechnology for mining: The potential of an emerging technology, the Andean Pact Copper Project and some policy implicationsDevelopment and Change169312110.1111/j.1467-7660.1985.tb00203.x.

102 

Xu, T., Ramanathan, T. & Ting, Y. (2014). Bioleaching of incineration fly ash by Aspergillus niger - Precipitation of metallic salt crystals and morphological alteration of the fungus. Biotechnology Reports, 3, 8-14.

T. Xu T. Ramanathan Y. Ting 2014Bioleaching of incineration fly ash by Aspergillus niger - Precipitation of metallic salt crystals and morphological alteration of the fungusBiotechnology Reports38-14

103 

Yang, Q. Z., Qi, G. J., Low, H. C. & Song, B. (2011). Sustainable recovery of nickel from spent hydrogenation catalyst: economics, emissions and wastes assessment. Journal of Cleaner Production , 19, 365-375. DOI: 10.1016/j.jclepro.2010.11.007.

Q. Z. Yang G. J. Qi H. C. Low B. Song 2011Sustainable recovery of nickel from spent hydrogenation catalyst: economics, emissions and wastes assessmentJournal of Cleaner Production1936537510.1016/j.jclepro.2010.11.007.

104 

Yoo, J. S. (1998). Metal recovery and rejuvenation of metal-loaded spent catalysts. Catalysis Today , 44, 27-46. DOI: 10.1016/S0920-5861(98)00171-0.

J. S. Yoo 1998Metal recovery and rejuvenation of metal-loaded spent catalystsCatalysis Today44274610.1016/S0920-5861(98)00171-0.

105 

Zeiringer, H. (1979). Preparation of abrasive material from spent catalysts. US patent 4,142,871.

H. Zeiringer 1979Preparation of abrasive material from spent catalystsUS patent 4,142,871



This display is generated from NISO JATS XML with jats-html.xsl. The XSLT engine is libxslt.

Enlaces refback

  • No hay ningún enlace refback.


Financiado por:

 

Proyecto C-297282

Licencia Creative Commons
TIP Revista Especializada en Ciencias Químico-Biológicas está distribuido bajo una Licencia Creative Commons Atribución-NoComercial-SinDerivar 4.0 Internacional.

TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS, Volumen 23, 2020, es una publicación editada por la Universidad Nacional Autónoma de México, Ciudad Universitaria, Deleg. Coyoacán, C.P. 04510, Ciudad de México, México, a través de la Facultad de Estudios Superiores Zaragoza, Campus I, Av. Guelatao # 66, Col. Ejército de Oriente, Deleg. Iztapalapa, C.P. 09230, Ciudad de México, México, Teléfono: 55.56.23.05.27, http://tip.zaragoza.unam.mx, Correo electrónico revistatip@yahoo.com, Editor responsable: Dra. Martha Asunción Sánchez Rodríguez, Certificado de Reserva de Derechos al Uso Exclusivo del Título No. 04-2014-062612263300-203, ISSN impreso: 1405-888X, ISSN electrónico: 2395-8723, otorgados por el Instituto Nacional del Derecho de Autor, Responsable de la última actualización de este número Claudia Ahumada Ballesteros, Facultad de Estudios Superiores Zaragoza, Av. Guelatao # 66, Col. Ejército de Oriente, Deleg. Iztapalapa, C.P. 09230, Ciudad de México, México, fecha de la última modificación, 28 de julio de 2020.

Esta página puede ser reproducida con fines no lucrativos, siempre y cuando no se mutile, se cite la fuente completa y su dirección electrónica. De otra forma requiere permiso previo de la institución.