A reagent combination of sodium oleate(NaOl)and salicyl hydroximic acid was employed as the roughing and scavenging collectors,whereas styryl phosphoric acid(SPA)and octanol were employed as the cleaning collectors.Re...A reagent combination of sodium oleate(NaOl)and salicyl hydroximic acid was employed as the roughing and scavenging collectors,whereas styryl phosphoric acid(SPA)and octanol were employed as the cleaning collectors.Results of bench-scale flotation demonstrate that the dosage of SPA can be reduced by about 80%,and that a better flotation index can be obtained using the proposed reagent system.The results of adsorption amount and contact angle measurements indicate that the rutile surface adsorbed not only a large amount of residual NaOl but also SPA and a small amount of NaOl remained on the amphibole surface in strong acidic solution.The hydrophobic difference between rutile and amphibole surfaces was therefore amplified in cleaning,and their further separation became much easier consequently.展开更多
Co(Ⅱ)and Ni(Ⅱ)are two common toxic heavy metals,and may simultaneously exist in contaminated water,soil,and sediment systems in Earth’s surface environment.Under this circumstance,competitive adsorption between the...Co(Ⅱ)and Ni(Ⅱ)are two common toxic heavy metals,and may simultaneously exist in contaminated water,soil,and sediment systems in Earth’s surface environment.Under this circumstance,competitive adsorption between the two metals may influence their migration,toxicity,and bioavailability.In this research,the competitive sorption of Co(Ⅱ)and Ni(Ⅱ)on γ-Al_2O_3was studied using both macroscopic sorption experiments and extended X-ray absorption fine structure(EXAFS)spectroscopy.Results suggest that Ni(Ⅱ)reduced the amount of Co(Ⅱ)sorption in a binary-solute system at pH 6.0.This is because both Co(Ⅱ)and Ni(Ⅱ)form inner-sphere surface complexes during sorption on γ-Al_2O_3and compete for the surface reactive sites.However,Co(Ⅱ)exhibited a negligible influence on sorption amount of Ni(Ⅱ)under the same conditions,which suggests Ni(Ⅱ)has a stronger affinity to alumina surface.At pH 7.5,Co(Ⅱ)and Ni(Ⅱ)sorption density were much higher than that at pH 6.0,but there no mutual competitive effect was observed.EXAFS analysis further revealed that formation of layered double-hydrated precipitates was the dominant sorption mechanism for both Co(Ⅱ)and Ni(Ⅱ)at pH 7.5.Because this type of sorption does not rely on surface reactive sites,there was no competition between Co(Ⅱ)and Ni(Ⅱ).This finding sheds light on risk assessment and remediation of Ni/Co pollution.展开更多
基金Projects(11575281,11290165,11305252,U1532260,51474254)supported by the National Natural Science Foundation of China
文摘A reagent combination of sodium oleate(NaOl)and salicyl hydroximic acid was employed as the roughing and scavenging collectors,whereas styryl phosphoric acid(SPA)and octanol were employed as the cleaning collectors.Results of bench-scale flotation demonstrate that the dosage of SPA can be reduced by about 80%,and that a better flotation index can be obtained using the proposed reagent system.The results of adsorption amount and contact angle measurements indicate that the rutile surface adsorbed not only a large amount of residual NaOl but also SPA and a small amount of NaOl remained on the amphibole surface in strong acidic solution.The hydrophobic difference between rutile and amphibole surfaces was therefore amplified in cleaning,and their further separation became much easier consequently.
基金co-funded by the National Natural Science Foundation of China(No.41473084)the Project of China Geological Survey(No.12120114092001)the 1000 Youth Talent program
文摘Co(Ⅱ)and Ni(Ⅱ)are two common toxic heavy metals,and may simultaneously exist in contaminated water,soil,and sediment systems in Earth’s surface environment.Under this circumstance,competitive adsorption between the two metals may influence their migration,toxicity,and bioavailability.In this research,the competitive sorption of Co(Ⅱ)and Ni(Ⅱ)on γ-Al_2O_3was studied using both macroscopic sorption experiments and extended X-ray absorption fine structure(EXAFS)spectroscopy.Results suggest that Ni(Ⅱ)reduced the amount of Co(Ⅱ)sorption in a binary-solute system at pH 6.0.This is because both Co(Ⅱ)and Ni(Ⅱ)form inner-sphere surface complexes during sorption on γ-Al_2O_3and compete for the surface reactive sites.However,Co(Ⅱ)exhibited a negligible influence on sorption amount of Ni(Ⅱ)under the same conditions,which suggests Ni(Ⅱ)has a stronger affinity to alumina surface.At pH 7.5,Co(Ⅱ)and Ni(Ⅱ)sorption density were much higher than that at pH 6.0,but there no mutual competitive effect was observed.EXAFS analysis further revealed that formation of layered double-hydrated precipitates was the dominant sorption mechanism for both Co(Ⅱ)and Ni(Ⅱ)at pH 7.5.Because this type of sorption does not rely on surface reactive sites,there was no competition between Co(Ⅱ)and Ni(Ⅱ).This finding sheds light on risk assessment and remediation of Ni/Co pollution.
