title: Characteristics of equilibrium, kinetics studies for adsorption of fluoride on magnetic-chitosan particle.
abstract: The magnetic-chitosan particle was prepared and characterized by the SEM, XRD, FT-IR and employed as an adsorbent for removal fluoride from the water solution in the batch system. The Langmuir isotherms, Bradley's isotherm, Freundlich isotherm and Dubinin-Kaganer-Radushkevich (DKR) isotherm were used to describe adsorption equilibrium. The kinetic process was investigated using the pseudo-first-order model, pseudo-second-order model and intra-particle diffusion model, respectively. The results show that the magnetic-chitosan particle is amorphous of irregular clumps in the surface with groups of RNH(2), RNH(3), Fe-O, etc. Bradley's equation and two-sites Langmuir isotherms were fitted well with the adsorption equilibrium data; the maximal amount of adsorption of 20.96-23.98 mg/l and free energy of 2.48 kJ/mol were obtained from the Bradley's equation, two-sites Langmuir isotherm and DKR modeling, respectively. The pseudo-second-order with the initial adsorption rate 2.08 mg/g min was suitable to describe the kinetic process of fluoride adsorption onto the adsorbent. In overall, the major mechanism of fluoride adsorption onto the heterogeneous surface of magnetic-chitosan particle was proposed in the study.
authors.affiliation: Department of Chemistry, College of Chemical Engineering, Dalian University of Technology, Dalian 116023, China. mawei@dlut.edu.cn
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.forename: Fei-Qun
authors.initials: FQ
authors.lastname: Ya
authors.forename: Mei
authors.initials: M
authors.lastname: Han
authors.forename: Ren
authors.initials: R
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008280:Magnetics; D013816:Thermodynamics; D018508:Water Purification / Q000379:methods*
chemical_list: D048271:Chitosan; D005459:Fluorides