title: High-capacity adsorption of hexavalent chromium from aqueous solution using magnetic microspheres by surface dendrimer graft modification.
abstract: The magnetic poly-(methyl acrylate-divinyl benzene) (MA-DVB) microspheres with micron size were synthesized by modified suspension polymerization method. Through stepwise reaction with methyl acrylate (MA) and ethylenediamine (EDA), the magnetic poly-(MA-DVB) microspheres with surface dendrimer containing amino groups were obtained. The above mentioned magnetic microspheres were applied for the adsorption of hexavalent chromium from aqueous solution. The effects of solution pH value, adsorption temperature, and adsorption and desorption of Cr(VI) were studied. The results showed that the optimum pH value for Cr(VI) adsorption was found at pH=3, and the adsorption capacity increased with the increase in adsorption temperature. The adsorption equilibrium of Cr(VI) was obtained in about 12 min and more than 98% of adsorbed Cr(VI) were desorbed from the magnetic microspheres in about 30 min using Na(2)SO(4) solution. By fitting the experimental data to Langmuir equation, the maximum capacity for Cr(VI) of magnetic poly-(MA-DVB) microspheres was estimated at 231.8 mg/g.
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Yueping
authors.initials: Y
authors.lastname: Guan
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Ren
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Yang
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000327:Adsorption; D002857:Chromium / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D005029:Ethylenediamines / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D059346:Magnets / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D012996:Solutions; D013343:Styrenes / Q000138:chemical synthesis / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000179:Acrylates; D050091:Dendrimers; D005029:Ethylenediamines; D012996:Solutions; D013343:Styrenes; D014874:Water Pollutants, Chemical; C530114:methyl acrylate-co-divinylbenzene; D014867:Water; D002857:Chromium; C074702:chromium hexavalent ion; C031234:ethylenediamine; C035956:methyl acrylate