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Adsorption of ga(III) on oxidized coir / Umesh Suryavanshi in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 870–876 Titre : Adsorption of ga(III) on oxidized coir Type de document : texte imprimé Auteurs : Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur Année de publication : 2009 Article en page(s) : p. 870–876 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Processing  Technology Résumé : Gallium is a strategic material due to its high-tech applications, but its availability in minerals is extremely poor to ensure economically feasible recovery. It is possible through the processing of other Ga-containing minerals, during which Ga gets concentrated. In the present work, Batch-wise adsorption of Ga(III) from the aqueous solution of gallium nitrate having different concentrations was attempted on unmodified (UC) and oxidized coir (OC). The SEM micrographs of OC show more porous structure due to the removal of pits from the coir surface by oxidation, leading to a 1.5× increase in the surface area. The effect of increasing pH from 1 to 3 greatly enhanced the adsorption. At pH 3, as high as a 70.53% adsorption was achieved on OC, beyond which Ga does not remain in solution form. Ga(III), being a trivalent ion, possesses substantial acidity, which increases with its concentration. The mechanism of Ga(III) adsorption on UC and OC has been put forward based on ion exchange. The adsorption fits to the Langmuir isotherm model and has been shown to obey pseudo second order kinetics. Considerably high adsorption capacity is gained by the coir upon simple oxidation treatment. The maximum adsorption capacity of OC was observed to be 19.42 mg g−1, as compared to 13.75 mg g−1 for UC. Desorption using 0.5 M HCl leads to nearly complete recovery of Ga(III) without affecting the physical characteristics of the adsorbent, like strength and crystallinity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801259c [article] Adsorption of ga(III) on oxidized coir [texte imprimé] / Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur . - 2009 . - p. 870–876. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 870–876 Mots-clés : Processing  Technology Résumé : Gallium is a strategic material due to its high-tech applications, but its availability in minerals is extremely poor to ensure economically feasible recovery. It is possible through the processing of other Ga-containing minerals, during which Ga gets concentrated. In the present work, Batch-wise adsorption of Ga(III) from the aqueous solution of gallium nitrate having different concentrations was attempted on unmodified (UC) and oxidized coir (OC). The SEM micrographs of OC show more porous structure due to the removal of pits from the coir surface by oxidation, leading to a 1.5× increase in the surface area. The effect of increasing pH from 1 to 3 greatly enhanced the adsorption. At pH 3, as high as a 70.53% adsorption was achieved on OC, beyond which Ga does not remain in solution form. Ga(III), being a trivalent ion, possesses substantial acidity, which increases with its concentration. The mechanism of Ga(III) adsorption on UC and OC has been put forward based on ion exchange. The adsorption fits to the Langmuir isotherm model and has been shown to obey pseudo second order kinetics. Considerably high adsorption capacity is gained by the coir upon simple oxidation treatment. The maximum adsorption capacity of OC was observed to be 19.42 mg g−1, as compared to 13.75 mg g−1 for UC. Desorption using 0.5 M HCl leads to nearly complete recovery of Ga(III) without affecting the physical characteristics of the adsorbent, like strength and crystallinity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801259c

Adsorption of Pb2+ by alkali - treated citrus limetta peels / Umesh Suryavanshi in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11682–11688 Titre : Adsorption of Pb2+ by alkali - treated citrus limetta peels Type de document : texte imprimé Auteurs : Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur Année de publication : 2011 Article en page(s) : pp. 11682–11688 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Résumé : The biomass Citrus limetta fruit peels was subjected to Pb2+ adsorption from aqueous PbNO3 solutions of different concentrations. Pretreatment of the biomass using cold alkali enhanced the adsorption by 87% even after considering the percentage weight loss. The biomass was characterized by scanning electron microscopy (SEM), electrokinetic analysis, and FT-IR spectroscopy. The equilibrium sorption capacity was observed to be 630 mg/g and the adsorption obeyed the Langmuir, Dubinin−Radushkevich (D−R), and ion-exchange models. The optimum pH and biomass concentration for maximum adsorption capacity were observed to be 4.5 and 0.1 g/L, respectively. Almost 80% sorption takes place within the first 15 min. The role of carboxylic and other functional groups was revealed to be ion exchange with a 1:2 stoichiometry between Pb2+ and carboxylic groups. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101491w [article] Adsorption of Pb2+ by alkali - treated citrus limetta peels [texte imprimé] / Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur . - 2011 . - pp. 11682–11688. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11682–11688 Mots-clés : Adsorption Résumé : The biomass Citrus limetta fruit peels was subjected to Pb2+ adsorption from aqueous PbNO3 solutions of different concentrations. Pretreatment of the biomass using cold alkali enhanced the adsorption by 87% even after considering the percentage weight loss. The biomass was characterized by scanning electron microscopy (SEM), electrokinetic analysis, and FT-IR spectroscopy. The equilibrium sorption capacity was observed to be 630 mg/g and the adsorption obeyed the Langmuir, Dubinin−Radushkevich (D−R), and ion-exchange models. The optimum pH and biomass concentration for maximum adsorption capacity were observed to be 4.5 and 0.1 g/L, respectively. Almost 80% sorption takes place within the first 15 min. The role of carboxylic and other functional groups was revealed to be ion exchange with a 1:2 stoichiometry between Pb2+ and carboxylic groups. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101491w