title: Preparation of organically functionalized silica gel as adsorbent for copper ion adsorption.
abstract: A novel adsorbent (AMPS-silica) was synthesized by bounding AMPS (2-acrylamido-2-methylpropanesulfonic acid) onto silica surface, which functioned with y-methacryloxypropyltrimethoxysilane reagent. The adsorbent was characterized by nitrogen adsorption/desorption measurement, thermogravimetric analysis (TGA) and potentiometric titration analysis. The TGA result indicated that the surface modification reactions introduced some organic functional groups onto the surface of silica. The surface area of AMPS-silica was 389.7 m2/g. The adsorbent was examined for copper ion removal in series of batch adsorption experiments. Results showed that the adsorption of Cu2+ onto AMPS-silica was pH dependent, and the adsorption capacity increased with increasing pH from 2 to 6. The adsorption kinetics showed that Cu2+ adsorption was fast and the data fitted well with a pseudo second- order kinetic model. The adsorption of Cu2+ onto AMPS-silica obeyed both Freundlich and Langmuir isotherms, with r2 = 0.993 and r2 = 0.984, respectively. The maximum Cu2+ adsorption capacity was 19.9 mg/g. The involved mechanism might be the adsorption through metal binding with organic functional groups such as carboxyl, amino and sulfonic groups. Cu2+ loaded on AMPS-silica could be desorbed in HNO3 solution, and the adsorption properties remain stable after three adsorption-desorption cycles.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. whj_99@hotmail.com
authors.forename: Hongjie
authors.initials: H
authors.lastname: Wang
authors.forename: Jin
authors.initials: J
authors.lastname: Kang
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liu
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000327:Adsorption; D000476:Alkanesulfonates / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013818:Thermogravimetry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000476:Alkanesulfonates; D014874:Water Pollutants, Chemical; C056288:2-acrylamido-2-methylpropanesulfonate; D058428:Silica Gel; D012822:Silicon Dioxide; D003300:Copper