title: Removal of Cd2+ from aqueous solution by adsorption using Fe-montmorillonite.
abstract: Fe-montmorillonite (Fe-Mont.) is obtained by exchanging the original interlayer cations of montmorillonite by poly-hydroxyl ferric. In this paper, Fe-Mont. was synthesized by using Ca-montmorillonite (Ca-Mont.) directly under ultrasonic treatment with the aim to enhance the ability of removal of heavy metal ions from wastewater. The modified materials were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR). Batch equilibrium experiments of Cd(II) ions (Cd(2+)) adsorption on the Fe-Mont. were performed. Effects of the initial pH of the solution and contact time on the adsorption of Cd(2+) were studied. Four types of adsorption isotherms were applied to describe the adsorption isotherms of Cd(2+) by Fe-Mont. The relationship between adsorbing capacity (q(e)) and equilibrium mass concentration (C(e)) is in accordance with the isothermal adsorption equation of Langmuir. Three kinetic models, including pseudo-first-order, pseudo-second-order and the Elovich equation model, were used to analyze the Cd(2+) adsorption process. The pseudo-second-order chemical reaction kinetics provide the best correlation of the experimental data, therefore the adsorption dynamics follows the laws of pseudo-second-order kinetics.
authors.affiliation: College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510640, PR China. pppxwu@scut.edu.cn
authors.forename: Pingxiao
authors.initials: P
authors.lastname: Wu
authors.forename: Weimin
authors.initials: W
authors.lastname: Wu
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Xing
authors.forename: Nengwu
authors.initials: N
authors.lastname: Zhu
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Jinghua
authors.initials: J
authors.lastname: Wu
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002104:Cadmium / Q000302:isolation & purification*; D007220:Industrial Waste / Q000517:prevention & control; D007501:Iron; D007700:Kinetics; D019216:Metals, Heavy / Q000302:isolation & purification; D012996:Solutions; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D007220:Industrial Waste; D019216:Metals, Heavy; D012996:Solutions; D014874:Water Pollutants, Chemical; D002104:Cadmium; D001546:Bentonite; D007501:Iron