title: Adsorption of a cationic dye (methylene blue) onto spent activated clay.
abstract: The adsorption characteristics of methylene blue (MB) onto spent activated clay (SAC), a waste produced from an edible oil manufacturer was investigated. Results showed that the adsorption increased with increasing MB concentration, temperature, and pH. The adsorption equilibrium data was well fitted by multilayer adsorption isotherm. The maximum adsorption capacities for MB ranged from 0.94x10(-4) to 3.41x10(-4)mol/g between 5 and 45 degrees C. Thermodynamic parameters suggest that the adsorption is spontaneous and endothermic. We proposed a modified double exponential equation accounting both with chemical and mathematical point of view to describe the adsorption kinetic data. The increases of mass transfer and adsorption capacity were mainly attributed to the interlayer of the SAC expanding at higher temperature. An activation energy of 13.5 kcal/Kmol was determined suggesting that the adsorption involved a chemical reaction mechanism.
authors.affiliation: Department of Civil and Ecological Engineering, I-Shou University, Da-Hsu Township, Kaohsiung 84008, Taiwan. chweng@isu.edu.tw
authors.forename: Chih-Huang
authors.initials: CH
authors.lastname: Weng
authors.forename: Yi-Fong
authors.initials: YF
authors.lastname: Pan
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D004396:Coloring Agents / Q000737:chemistry*; D003247:Conservation of Natural Resources; D005525:Food-Processing Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008751:Methylene Blue / Q000737:chemistry*; D009821:Oils; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000538:Aluminum Silicates; D004396:Coloring Agents; D007220:Industrial Waste; D009821:Oils; D014874:Water Pollutants, Chemical; D000077215:Clay; D008751:Methylene Blue