title: Investigation of adsorption capacity of N-carboxymethyl chitosan for Pb(II) ions.
abstract: N-carboxymethyl chitosan (NCMC) was prepared by reacting chitosan (CTS) with chloroacetic acid and characterized by (13)C-NMR spectroscopy to confirm that carboxymethylation occurred only in the amino groups. The adsorption properties of CTS, NCMC and O-carboxymethyl chitosan (OCMC) towards Pb(II) ions were evaluated and the order of the adsorption capacity was as follows: NCMC > OCMC > CTS. The effects of initial pH value (2.0-5.5) of the solutions and contact time (5-120 min) on adsorption of Pb(II) were investigated and the kinetic data were evaluated using the pseudo-first-order and pseudo-second-order models. Kinetics study showed that the adsorption process followed second-order kinetics rather than the first-order one. Furthermore, the experimental equilibrium data of Pb(II) on the NCMC were analyzed using the Langmuir and Freundlich isotherm models and the results indicated that the Langmuir model gave a better fit than the Freundlich equation and the maximum adsorption capacity obtained from the Langmuir model was 421.9 mg g(-1).
authors.affiliation: School of Biochemical and Engineering, Anhui Polytechnic University, Wuhu, 241000, China E-mail: gaojiangang@ahpu.edu.cn.
authors.forename: Chongxia
authors.initials: C
authors.lastname: Wang
authors.forename: Qingping
authors.initials: Q
authors.lastname: Song
authors.forename: Jiangang
authors.initials: J
authors.lastname: Gao
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: C504164:O-carboxymethylchitosan; D014874:Water Pollutants, Chemical; D007854:Lead; C068302:N-(carboxymethyl)chitosan; D048271:Chitosan