title: Sorption properties of the activated carbon-zeolite composite prepared from coal fly ash for Ni(2+), Cu(2+), Cd(2+) and Pb(2+).
abstract: Composite materials of activated carbon and zeolite have been prepared successfully by activating coal fly ash (CFA) by fusion with NaOH at 750 degrees C in N(2) followed by hydrothermal treatments under various conditions. Uptake experiments for Ni(2+), Cu(2+), Cd(2+) and Pb(2+) were performed with the materials thus obtained from CFA. Of the various composite materials, that were obtained by hydrothermal treatment with NaOH solution (ca. 4M) at 80 degrees C (a composite of activated carbon and zeolite X/faujasite) proved to be the most suitable for the uptake of toxic metal ions. The relative selectivity of the present sorbents for the various ions was Pb(2+)>Cu(2+)>Cd(2+)>Ni(2+), with equilibrium uptake capacities of 2.65, 1.72, 1.44 and 1.20mmol/g, respectively. The sorption isotherm was a good fit to the Langmuir isotherm and the sorption is thought to progress mainly by ion exchange with Na(+). The overall reaction is pseudo-second order with rate constants of 0.14, 0.17, 0.21 and 0.20Lg/mmol min for the uptake of Pb(2+), Cu(2+), Cd(2+) and Ni(2+), respectively.
authors.affiliation: Department of Material and Energy Science, Graduate School of Environmental Science, Okayama University, Tsushima-Naka, Okayama, Japan. vinayj2@yahoo.com
authors.forename: Vinay Kumar
authors.initials: VK
authors.lastname: Jha
authors.forename: Motohide
authors.initials: M
authors.lastname: Matsuda
authors.forename: Michihiro
authors.initials: M
authors.lastname: Miyake
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000032:analysis; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D060729:Coal Ash; D003300:Copper / Q000032:analysis; D007700:Kinetics; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission; D013816:Thermodynamics; D017641:Zeolites / Q000737:chemistry*
chemical_list: D060729:Coal Ash; D019216:Metals, Heavy; D052638:Particulate Matter; D002104:Cadmium; D017641:Zeolites; D007854:Lead; D002244:Carbon; D003300:Copper; D009532:Nickel