Adsorption of basic dyes in aqueous solution by clay adsorbent from regenerated bleaching earth

• DOI: 10.1016/j.clay.2004.10.004
• Publication Date: 2004-12-15T18:20:25Z
• Authors: W.T. Tsai; Y.M. Chang; C.W. Lai; C.C. Lo
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract Regenerated bleaching earth was used for adsorption and adsorption kinetics of the three basic dyes violet 4, violet 3 and red 9 from aqueous solution. The rate of adsorption has been investigated under various parameters such as initial dye concentration, pH and temperature. Two simple models (i.e., pseudo-second-order reaction and intra-particle diffusion) have been tested to predict the adsorption parameters. The adsorption of the basic dyes by regenerated bleaching earth at lower initial concentrations follows the order: basic violet 4>basic violet 3>basic red 9, parallel to the molecular weights and molecular sizes of the basic dyes. Further, the adsorption kinetic of the basic dyes can be well described with the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir and Freundlich models for adsorption of basic violet 4 and basic red 9 yield relatively better fits than that for adsorption of basic violet 3.