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Extraction of nickel from spent catalyst using biodegradable chelating agent EDDS / Garima Chauhan in Industrial & engineering chemistry research, Vol.51 N° 31 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10354-10363 Titre : Extraction of nickel from spent catalyst using biodegradable chelating agent EDDS Type de document : texte imprimé Auteurs : Garima Chauhan, Auteur ; Kamal K. Pant, Auteur ; Krishna D. P. Nigam, Auteur Année de publication : 2012 Article en page(s) : pp. 10354-10363 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chelating  agent  Catalyst Résumé : Literature suggests that ethylene-diamine-tetraacetic acid (EDTA) has been proved as a successful chelating agent for the extraction of metals from soils and spent catalysts. EDTA, however, is quite persistent in the environment due to its low biodegradability, thus its use becomes a matter of environmental concern. Therefore, to minimize the potential environmental risks, a new chelating agent [S,S]-ethylene-diamine-disuccinic-acid ([S,S]-EDDS) can be considered as an environmentally benign substitute for EDTA due to its easy biodegradation capability. The present study focuses on the effectiveness of biodegradable chelating agent [S,S]-EDDS for extraction of nickel from the spent catalyst of fertilizer industry. Experiments were carried out in batch mode under reflux conditions and process design parameters were optimized to maximize the extraction efficiency. Ni extraction of 84% was attained at optimum reaction condition in one cycle run. Dechelation of Ni-EDDS complex was performed at pH 5 where more than 96% EDDS was recovered. Results of the present study were compared with the previously studied chelating agent EDTA at optimum reaction conditions reported in literature. It was observed that [S,S]-EDDS requires a narrower pH range as compared to EDTA for chelation-dechelation process. Thus milder reaction conditions were employed for metal extraction using EDDS which is favorable to select the material of construction of equipment, in addition to the added advantage of biodegradability. Kinetic study was also performed for the noncatalyzed extraction process using shrinking core model and the process was found to be diffusion controlled under experimental conditions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26234066 [article] Extraction of nickel from spent catalyst using biodegradable chelating agent EDDS [texte imprimé] / Garima Chauhan, Auteur ; Kamal K. Pant, Auteur ; Krishna D. P. Nigam, Auteur . - 2012 . - pp. 10354-10363. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10354-10363 Mots-clés : Chelating  agent  Catalyst Résumé : Literature suggests that ethylene-diamine-tetraacetic acid (EDTA) has been proved as a successful chelating agent for the extraction of metals from soils and spent catalysts. EDTA, however, is quite persistent in the environment due to its low biodegradability, thus its use becomes a matter of environmental concern. Therefore, to minimize the potential environmental risks, a new chelating agent [S,S]-ethylene-diamine-disuccinic-acid ([S,S]-EDDS) can be considered as an environmentally benign substitute for EDTA due to its easy biodegradation capability. The present study focuses on the effectiveness of biodegradable chelating agent [S,S]-EDDS for extraction of nickel from the spent catalyst of fertilizer industry. Experiments were carried out in batch mode under reflux conditions and process design parameters were optimized to maximize the extraction efficiency. Ni extraction of 84% was attained at optimum reaction condition in one cycle run. Dechelation of Ni-EDDS complex was performed at pH 5 where more than 96% EDDS was recovered. Results of the present study were compared with the previously studied chelating agent EDTA at optimum reaction conditions reported in literature. It was observed that [S,S]-EDDS requires a narrower pH range as compared to EDTA for chelation-dechelation process. Thus milder reaction conditions were employed for metal extraction using EDDS which is favorable to select the material of construction of equipment, in addition to the added advantage of biodegradability. Kinetic study was also performed for the noncatalyzed extraction process using shrinking core model and the process was found to be diffusion controlled under experimental conditions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26234066

Recovery of nickel from spent industrial catalysts using chelating agents / Koteswara R Vuyyuru in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2014–2024 Titre : Recovery of nickel from spent industrial catalysts using chelating agents Type de document : texte imprimé Auteurs : Koteswara R Vuyyuru, Auteur ; Kamal K. Pant, Auteur ; Venkatesan V Krishnan, Auteur Année de publication : 2010 Article en page(s) : pp. 2014–2024 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Recovery  of  Nickel;  Chelating;  Industrial  Catalysts;  Acid  EDTA Résumé : The extraction of nickel from a spent primary steam reformer catalyst from an ammonia plant was carried out by chelation using ethylenediaminetetraacetic acid (EDTA) as the chelating agent. Ni recovery was optimized by varying the particle size distribution of catalyst (pretreatment of spent catalyst), stirring speed, temperature (particularly in an autoclave, where temperatures ranging from 100 to 200 °C were used), EDTA concentration, and solid-to-liquid ratio. Approximately 95% Ni recovery was achieved in the Ni extraction carried out under hydrothermal conditions in an autoclave, at temperatures of 150 °C and higher, over a 4-h period. The resulting Ni−EDTA complex was then “dechelated” using a mineral acid (H2SO4 and HNO3), resulting in the formation of a nickel nitrate or sulfate solution and the precipitation of EDTA (about 97% of the initial weight of EDTA was recovered). However, the chelation performance of Ni was shown to decrease with every successive recovery of EDTA (in the case of dechelation using H2SO4). EDX analysis of fresh and recovered EDTA established that fresh EDTA is a disodium salt whereas recovered EDTA is protonated. EDX analysis also indicated sulfur in the recovered EDTA when sulfuric acid was used for dechelation. TGA data showed a much larger weight loss in recovered EDTA in comparison to the fresh sample, probably because of a combination of two factors: the presence of sulfur species and the protonation of EDTA after recovery. It is likely that differences in recovered EDTA as evidenced by EDX analysis and TGA are responsible for the lowering the Ni chelation efficiency. This possibility is being investigated further as part of ongoing research. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901406e [article] Recovery of nickel from spent industrial catalysts using chelating agents [texte imprimé] / Koteswara R Vuyyuru, Auteur ; Kamal K. Pant, Auteur ; Venkatesan V Krishnan, Auteur . - 2010 . - pp. 2014–2024. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2014–2024 Mots-clés : Recovery  of  Nickel;  Chelating;  Industrial  Catalysts;  Acid  EDTA Résumé : The extraction of nickel from a spent primary steam reformer catalyst from an ammonia plant was carried out by chelation using ethylenediaminetetraacetic acid (EDTA) as the chelating agent. Ni recovery was optimized by varying the particle size distribution of catalyst (pretreatment of spent catalyst), stirring speed, temperature (particularly in an autoclave, where temperatures ranging from 100 to 200 °C were used), EDTA concentration, and solid-to-liquid ratio. Approximately 95% Ni recovery was achieved in the Ni extraction carried out under hydrothermal conditions in an autoclave, at temperatures of 150 °C and higher, over a 4-h period. The resulting Ni−EDTA complex was then “dechelated” using a mineral acid (H2SO4 and HNO3), resulting in the formation of a nickel nitrate or sulfate solution and the precipitation of EDTA (about 97% of the initial weight of EDTA was recovered). However, the chelation performance of Ni was shown to decrease with every successive recovery of EDTA (in the case of dechelation using H2SO4). EDX analysis of fresh and recovered EDTA established that fresh EDTA is a disodium salt whereas recovered EDTA is protonated. EDX analysis also indicated sulfur in the recovered EDTA when sulfuric acid was used for dechelation. TGA data showed a much larger weight loss in recovered EDTA in comparison to the fresh sample, probably because of a combination of two factors: the presence of sulfur species and the protonation of EDTA after recovery. It is likely that differences in recovered EDTA as evidenced by EDX analysis and TGA are responsible for the lowering the Ni chelation efficiency. This possibility is being investigated further as part of ongoing research. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901406e