title: Mechanisms of chromium and arsenite adsorption by amino-functionalized SBA-15.
abstract: The adsorption of Cr(VI) and As(III) by amino-functionalized SBA-15 (NH2-SBA-15) from single and binary systems were investigated in this work. The effects of pH and temperature on the adsorption of NH2-SBA-15 were studied. Adsorption kinetics, isotherm model, and thermodynamics were studied to analyze the experimental data. pH 2 was the optimum condition for the adsorption of Cr(VI) and pH 4 for As(III) adsorption. Increasing temperature had a positive effect on the removal of both Cr(VI) and As(III). The Freundlich isotherm model can depict the adsorption process best. The pseudo-second-order kinetic model fitted well with the kinetic data of Cr(VI) and As(III) in the single-component system. In the binary system, the adsorption of As(III) by NH2-SBA-15 was slightly enhanced with the presence of Cr(VI); however, As(III) had no obvious effect on the removal of Cr(VI). Regeneration experiments indicated that 0.1 mol/L NaHCO3 was an efficient desorbent for the recovery of Cr(VI) and As(III) from NH2-SBA-15; the desorption rates for Cr(VI) and As(III) were 91.6 and 33.59 %, respectively. After five recycling cycles, the removal rates were 88 and 7 % for Cr(VI) and As(III) adsorption by NH2-SBA-15, respectively.
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, China.
authors.forename: Yunhai
authors.initials: Y
authors.lastname: Wu
authors.affiliation: College of Environment, Hohai University, Nanjing, 210098, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Zhou
authors.affiliation: College of Environment, Hohai University, Nanjing, 210098, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Jin
authors.affiliation: College of Environment, Hohai University, Nanjing, 210098, China.
authors.forename: Julin
authors.initials: J
authors.lastname: Cao
authors.affiliation: College of Environment, Hohai University, Nanjing, 210098, China.
authors.forename: Palizhati
authors.initials: P
authors.lastname: Yilihan
authors.affiliation: College of Environment, Hohai University, Nanjing, 210098, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Wen
authors.affiliation: Department of Chemistry, Hanshan Normal University, Chaozhou, Guangdong Province, China. hjywyh@hhu.edu.cn.
authors.forename: Yunying
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D018053:Arsenites / Q000032:analysis / Q000737:chemistry*; D002857:Chromium / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D018053:Arsenites; C509969:SBA-15; D014874:Water Pollutants, Chemical; D002857:Chromium; D012822:Silicon Dioxide; C015001:arsenite