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Adsorption of sodium dodecyl benzene sulfonate from aqueous solution using a modified natural zeolite with CTAB / Silvio R. Taffarel in Minerals engineering, Vol. 23 N° 10 (Septembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 771–779 Titre : Adsorption of sodium dodecyl benzene sulfonate from aqueous solution using a modified natural zeolite with CTAB Type de document : texte imprimé Auteurs : Silvio R. Taffarel, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 771–779 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Zeolite  Zeolite  modification  Adsorption  Sodium  dodecyl  benzene  sulfonate  Water  treatment Résumé : This paper describes studies of surface modification of a natural Chilean zeolite with cetyl trimethylammonium bromide (CTAB), to investigate the adsorption efficiency for the removal from aqueous solution of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS), at bench scale. Modification of the zeolite with CTAB (named ZMS) was based on the external cation exchange capacity (ECEC) of 0.11 meq g−1. The medium pH influences the SDBS ions adsorption rate onto ZMS and the adsorption followed the pseudo-second-order kinetic model. Equilibrium data showed excellent correlation with the Langmuir isotherm model. The adsorption capacities depended on maximum uptakes followed the CTAB concentration or coverage ranging from 40% to 660% of the ECEC. The maximum adsorption capacity of 30.7 mg SDBS g−1 was obtained at 660% of ECEC value. These data contribute for the understanding of mechanisms involved in zeolite modification and provide same practical clues to improve the adsorption efficiency (uptake capacity) of anionic surfactants. Results were discussed in terms of interfacial and solution chemistry phenomena. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001512 [article] Adsorption of sodium dodecyl benzene sulfonate from aqueous solution using a modified natural zeolite with CTAB [texte imprimé] / Silvio R. Taffarel, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 771–779. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 771–779 Mots-clés : Zeolite  Zeolite  modification  Adsorption  Sodium  dodecyl  benzene  sulfonate  Water  treatment Résumé : This paper describes studies of surface modification of a natural Chilean zeolite with cetyl trimethylammonium bromide (CTAB), to investigate the adsorption efficiency for the removal from aqueous solution of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS), at bench scale. Modification of the zeolite with CTAB (named ZMS) was based on the external cation exchange capacity (ECEC) of 0.11 meq g−1. The medium pH influences the SDBS ions adsorption rate onto ZMS and the adsorption followed the pseudo-second-order kinetic model. Equilibrium data showed excellent correlation with the Langmuir isotherm model. The adsorption capacities depended on maximum uptakes followed the CTAB concentration or coverage ranging from 40% to 660% of the ECEC. The maximum adsorption capacity of 30.7 mg SDBS g−1 was obtained at 660% of ECEC value. These data contribute for the understanding of mechanisms involved in zeolite modification and provide same practical clues to improve the adsorption efficiency (uptake capacity) of anionic surfactants. Results were discussed in terms of interfacial and solution chemistry phenomena. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001512

Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation / Erico Tabosa in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1198–1206 Titre : Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation Type de document : texte imprimé Auteurs : Erico Tabosa, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 1198–1206 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  High  intensity  conditioning  Concentrate  recycling  Copper  sulphide  fines Résumé : This paper describes the effect of the partial concentrate (rougher floated product) recirculation to rougher flotation feed, here named concentrate recirculation flotation – CRF, at laboratory scale. The main parameters used to evaluate this alternative approach were flotation rate and recovery of fine (“F” 40–13 μm) and ultrafine (“UF” <13 μm) copper sulphide particles. Also, the comparative effect of high intensity conditioning (HIC), as a pre-flotation stage for the rougher flotation, was studied alone or combined with CRF. Results were evaluated through separation parameters, grade-recovery and flotation rates, especially in the fine and ultrafine fractions, a very old problem of processing by flotation. Results showed that the floated concentrate recirculation enhanced the metallurgical recovery, grade and rate flotation of copper sulphides. The best results were obtained with concentrate recirculation flotation combined with high intensity conditioning (CRF–HIC). The kinetics rate values doubled, the Cu recovery increased 17%, the Cu grade increased 3.6% and the flotation rates were 2.4 times faster. These were accompanied by improving 32% the “true” flotation values equivalent to 2.4 times lower the amount of entrained copper particles. These results were explained and proved to proceed by particle aggregation (among others) occurring after HIC, assisted by the recycled floatable particles. This “artificial” increase in valuable mineral grade (by the CR) resulted in higher collision probability between hydrophobic particles acting as “seeds” or “carrier”. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002037 [article] Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation [texte imprimé] / Erico Tabosa, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 1198–1206. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1198–1206 Mots-clés : Flotation  High  intensity  conditioning  Concentrate  recycling  Copper  sulphide  fines Résumé : This paper describes the effect of the partial concentrate (rougher floated product) recirculation to rougher flotation feed, here named concentrate recirculation flotation – CRF, at laboratory scale. The main parameters used to evaluate this alternative approach were flotation rate and recovery of fine (“F” 40–13 μm) and ultrafine (“UF” <13 μm) copper sulphide particles. Also, the comparative effect of high intensity conditioning (HIC), as a pre-flotation stage for the rougher flotation, was studied alone or combined with CRF. Results were evaluated through separation parameters, grade-recovery and flotation rates, especially in the fine and ultrafine fractions, a very old problem of processing by flotation. Results showed that the floated concentrate recirculation enhanced the metallurgical recovery, grade and rate flotation of copper sulphides. The best results were obtained with concentrate recirculation flotation combined with high intensity conditioning (CRF–HIC). The kinetics rate values doubled, the Cu recovery increased 17%, the Cu grade increased 3.6% and the flotation rates were 2.4 times faster. These were accompanied by improving 32% the “true” flotation values equivalent to 2.4 times lower the amount of entrained copper particles. These results were explained and proved to proceed by particle aggregation (among others) occurring after HIC, assisted by the recycled floatable particles. This “artificial” increase in valuable mineral grade (by the CR) resulted in higher collision probability between hydrophobic particles acting as “seeds” or “carrier”. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002037

On the removal of Mn2+ ions by adsorption onto natural and activated Chilean zeolites / Silvio Roberto Taffarel in Minerals engineering, Vol. 22 N° 4 (Mars 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 4 (Mars 2009) . - pp. 336–343 Titre : On the removal of Mn2+ ions by adsorption onto natural and activated Chilean zeolites Type de document : texte imprimé Auteurs : Silvio Roberto Taffarel, Auteur ; Jorge Rubio, Auteur Année de publication : 2009 Article en page(s) : pp. 336–343 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Zeolite  Metal  ions  Ion-exchange  Langmuir  isotherms  Water  treatment Résumé : This paper describes studies of preparation, activation and physical characterization of a Chilean zeolite (Ch-zeolite) employed as adsorbent for manganese ions from aqueous solutions. The zeolite sample, composed mainly of clinoptilolite and mordenite, had a specific surface area of 118 m2 g−1 (N2 adsorption), the particles were negatively charged in a wide pH range and presented a cation-exchange capacity of 1.09 meq View the MathML source. The medium pH influenced significantly the Mn2+ ions adsorption capacity and best results were obtained at pH 6–6.8. The adsorption onto the activated zeolite followed the pseudo-second-order kinetic model and activation of the Ch-zeolite with NaOH resulted in the highest reaction rate. The equilibrium data showed excellent correlation with the Langmuir isotherm model. Ch-zeolite modification by treating it with NaCl (0.77 meq Mn2+ g−1), NaOH (0.76 meq Mn2+ g−1), Na2CO3 (0.72 meq Mn2+ g−1) and NH4Cl (0.67 meq Mn2+ g−1) increased its uptake ability when compared with the natural Ch-zeolite (0.26 meq Mn2+ g−1). These data contribute to the understanding of mechanisms involved in zeolite activation and provide some practical clues to improve the adsorption efficiency (uptake capacity and kinetics) of manganese ions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002379 [article] On the removal of Mn2+ ions by adsorption onto natural and activated Chilean zeolites [texte imprimé] / Silvio Roberto Taffarel, Auteur ; Jorge Rubio, Auteur . - 2009 . - pp. 336–343. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 4 (Mars 2009) . - pp. 336–343 Mots-clés : Zeolite  Metal  ions  Ion-exchange  Langmuir  isotherms  Water  treatment Résumé : This paper describes studies of preparation, activation and physical characterization of a Chilean zeolite (Ch-zeolite) employed as adsorbent for manganese ions from aqueous solutions. The zeolite sample, composed mainly of clinoptilolite and mordenite, had a specific surface area of 118 m2 g−1 (N2 adsorption), the particles were negatively charged in a wide pH range and presented a cation-exchange capacity of 1.09 meq View the MathML source. The medium pH influenced significantly the Mn2+ ions adsorption capacity and best results were obtained at pH 6–6.8. The adsorption onto the activated zeolite followed the pseudo-second-order kinetic model and activation of the Ch-zeolite with NaOH resulted in the highest reaction rate. The equilibrium data showed excellent correlation with the Langmuir isotherm model. Ch-zeolite modification by treating it with NaCl (0.77 meq Mn2+ g−1), NaOH (0.76 meq Mn2+ g−1), Na2CO3 (0.72 meq Mn2+ g−1) and NH4Cl (0.67 meq Mn2+ g−1) increased its uptake ability when compared with the natural Ch-zeolite (0.26 meq Mn2+ g−1). These data contribute to the understanding of mechanisms involved in zeolite activation and provide some practical clues to improve the adsorption efficiency (uptake capacity and kinetics) of manganese ions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002379

Removal of Mn2+ from aqueous solution by manganese oxide coated zeolite / Silvio R. Taffarel in Minerals engineering, Vol. 23 N° 14 (Novembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 14 (Novembre 2010) . - pp. 1131–1138 Titre : Removal of Mn2+ from aqueous solution by manganese oxide coated zeolite Type de document : texte imprimé Auteurs : Silvio R. Taffarel, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 1131–1138 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Zeolite  Manganese  oxide  Adsorption  Metal  ions  Water  treatment Résumé : The preparation, characterization, and adsorption properties of Mn2+ by manganese oxide coated zeolite (MOCZ) and its ability in removing Mn2+ by adsorption were investigated. Characterization analyses were used to monitor the surface properties (and their changes) of the coated layer and metal adsorption sites on the surface of MOCZ. The adsorption experiments were carried out as a function of solution pH, adsorbent concentration and contact time. Binding of Mn2+ ions onto MOCZ was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Mn2+ adsorption by MOCZ, the medium pH decreased and enhanced with increasing adsorbent concentration. The pseudo-second-order model fitted better among all the kinetic models suggesting that the adsorption mechanism might be a chemisorption process. The equilibrium data showed excellent correlation for both Langmuir and Freundlich isotherm model and this implies both monolayer adsorption and a heterogeneous surface existence in MOCZ. At pH = 6, the Mn2+ uptake by MOCZ attained as high as 1.1 meq Mn2+ g−1 at equilibrium. The results suggested that MOCZ presents a fairly good potential as an adsorbent for an efficient removal of Mn2+ ions from aqueous solution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001767 [article] Removal of Mn2+ from aqueous solution by manganese oxide coated zeolite [texte imprimé] / Silvio R. Taffarel, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 1131–1138. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 14 (Novembre 2010) . - pp. 1131–1138 Mots-clés : Zeolite  Manganese  oxide  Adsorption  Metal  ions  Water  treatment Résumé : The preparation, characterization, and adsorption properties of Mn2+ by manganese oxide coated zeolite (MOCZ) and its ability in removing Mn2+ by adsorption were investigated. Characterization analyses were used to monitor the surface properties (and their changes) of the coated layer and metal adsorption sites on the surface of MOCZ. The adsorption experiments were carried out as a function of solution pH, adsorbent concentration and contact time. Binding of Mn2+ ions onto MOCZ was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Mn2+ adsorption by MOCZ, the medium pH decreased and enhanced with increasing adsorbent concentration. The pseudo-second-order model fitted better among all the kinetic models suggesting that the adsorption mechanism might be a chemisorption process. The equilibrium data showed excellent correlation for both Langmuir and Freundlich isotherm model and this implies both monolayer adsorption and a heterogeneous surface existence in MOCZ. At pH = 6, the Mn2+ uptake by MOCZ attained as high as 1.1 meq Mn2+ g−1 at equilibrium. The results suggested that MOCZ presents a fairly good potential as an adsorbent for an efficient removal of Mn2+ ions from aqueous solution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001767

Sulphate ions removal from an aqueous solution / Renato Silva in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1220–1226 Titre : Sulphate ions removal from an aqueous solution : I. Co-precipitation with hydrolysed aluminum-bearing salts Type de document : texte imprimé Auteurs : Renato Silva, Auteur ; Luciana Cadorin, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 1220–1226 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphate  ions  removal  pH  Aluminum-bearing  salts  Co-precipitation Résumé : The removal of sulphate ions constitutes one of the main challenges in the mining, metallurgical and chemical industries, among others. Sulphate removal from aqueous streams is by far one of the most difficult and onerous tasks in these industries, and most existing processes are inefficient and costly. This work presents a method to remove sulphate ions in an acidic medium based on co-precipitation with aluminum salts, namely AlCl3 and a polyaluminum salt (PAC), followed by filtration. Herein, the different Al species react differently with sulphate, forming soluble and insoluble complexes, the latter of which causes insolubility and allows for the removal. The reaction kinetics depend on the activity of the so-called Alb species (which are classified as polymeric) and was proved here by different techniques. Better results were obtained with the inorganic salt AlCl3, when compared to PAC, probably because of the higher activity of the Al species. Co-precipitation of sulphate depends highly on the pH (which is optimal at 4.5), the mass ratio between reagents and sulphate ions (which is optimal at 7:1) and time (10 min). Finally, it was concluded that the technique proposed here has good potential for the treatment of sulphate-bearing effluents, including acid mining drainage (AMD). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002153 [article] Sulphate ions removal from an aqueous solution : I. Co-precipitation with hydrolysed aluminum-bearing salts [texte imprimé] / Renato Silva, Auteur ; Luciana Cadorin, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 1220–1226. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1220–1226 Mots-clés : Sulphate  ions  removal  pH  Aluminum-bearing  salts  Co-precipitation Résumé : The removal of sulphate ions constitutes one of the main challenges in the mining, metallurgical and chemical industries, among others. Sulphate removal from aqueous streams is by far one of the most difficult and onerous tasks in these industries, and most existing processes are inefficient and costly. This work presents a method to remove sulphate ions in an acidic medium based on co-precipitation with aluminum salts, namely AlCl3 and a polyaluminum salt (PAC), followed by filtration. Herein, the different Al species react differently with sulphate, forming soluble and insoluble complexes, the latter of which causes insolubility and allows for the removal. The reaction kinetics depend on the activity of the so-called Alb species (which are classified as polymeric) and was proved here by different techniques. Better results were obtained with the inorganic salt AlCl3, when compared to PAC, probably because of the higher activity of the Al species. Co-precipitation of sulphate depends highly on the pH (which is optimal at 4.5), the mass ratio between reagents and sulphate ions (which is optimal at 7:1) and time (10 min). Finally, it was concluded that the technique proposed here has good potential for the treatment of sulphate-bearing effluents, including acid mining drainage (AMD). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002153