title: Dye adsorption on unburned carbon: kinetics and equilibrium.
abstract: Unburned carbon in fly ash is an important by-product from coal combustion. In this investigation, unburned carbon has been separated from fly ash and been employed as a low cost adsorbent for a basic dye adsorption (Rhodamine B) in aqueous solution. Adsorption isotherm and kinetics of adsorption have been investigated using batch experiments. It is found that dye adsorption capacity depends on initial concentration, pH of solution, and temperature. The adsorption isotherm can be described by Langmuir model and the adsorption capacity of Rhodamine B at 30, 40, and 50 degrees C can reach 9.7 x 10(-5), 1.14 x 10(-4), and 1.5 x 10(-4)mol g(-1), respectively. The pseudo first- and second-order kinetic models have been employed to fit the dynamic adsorption. It is found that the dynamic adsorption follows the pseudo second-order model. Thermodynamic calculations indicate that the adsorption is endothermic reaction with DeltaH degrees at 25 kJ mol(-1).
authors.affiliation: Department of Chemical Engineering, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia. wangshao@vesta.curtin.edu.au
authors.forename: Shaobin
authors.initials: S
authors.lastname: Wang
authors.forename: Huiting
authors.initials: H
authors.lastname: Li
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry* / Q000302:isolation & purification; D060729:Coal Ash; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control*; D007700:Kinetics; D008956:Models, Chemical; D009994:Osmolar Concentration; D052638:Particulate Matter; D012235:Rhodamines / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014877:Water Pollution, Chemical / Q000517:prevention & control*
chemical_list: D060729:Coal Ash; D004396:Coloring Agents; D007220:Industrial Waste; D052638:Particulate Matter; D012235:Rhodamines; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D002244:Carbon; C029773:rhodamine B