title: Adsorption of Pb(II) from aqueous solution by silica-gel supported hyperbranched polyamidoamine dendrimers.
abstract: The adsorption properties of silica-gel supported hyperbranched polyamidoamine dendrimers (SiO(2)-G0-SiO(2)-G4.0) have been investigated by batch method. The effect of pH of the solution, contact time, initial Pb(II) ion concentration, temperature and coexisting metal ions have been demonstrated. The results indicated that the optimum pH value was 5. Adsorption kinetics was found to follow the pseudo-second-order model and controlled by film diffusion. The adsorption isotherms were fitted by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Langmuir isotherm model was found to be more suitable to describe the equilibrium data, suggesting the uptake of Pb(II) ions by monolayer adsorption. From D-R isotherm model, the calculated mean free energy E demonstrated the adsorption processes occurred by chemical ion-exchange mechanism. FTIR analysis revealed that amine groups were mainly responsible for the adsorption of Pb(II) by amino-terminated adsorbents, while CO of ester groups also participated in the adsorption process of ester-terminated ones. The adsorbents can selectively adsorb Pb(II) from binary ion systems in the presence of Mn(II), Cu(II), Co(II), and Ni(II). Based on the results, it is concluded that SiO(2)-G0-SiO(2)-G4.0 had great potential for the removal of Pb(II) from aqueous solution.
authors.affiliation: School of Chemistry and Materials Science, Ludong University, Yantai 264025, PR China.
authors.forename: Yuzhong
authors.initials: Y
authors.lastname: Niu
authors.forename: Rongjun
authors.initials: R
authors.lastname: Qu
authors.forename: Changmei
authors.initials: C
authors.lastname: Sun
authors.forename: Chunhua
authors.initials: C
authors.lastname: Wang
authors.forename: Hou
authors.initials: H
authors.lastname: Chen
authors.forename: Chunnuan
authors.initials: C
authors.lastname: Ji
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xia
authors.initials: X
authors.lastname: Shao
authors.forename: Fanling
authors.initials: F
authors.lastname: Bu
mesh_terms: D000327:Adsorption; D050091:Dendrimers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry*; D058428:Silica Gel / Q000737:chemistry*; D012996:Solutions; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D050091:Dendrimers; C104700:PAMAM Starburst; D012996:Solutions; D014874:Water Pollutants, Chemical; D007854:Lead; D058428:Silica Gel