Adsorption of Amaranth Dye onto Alumina Reinforced Polystyrene

Adsorptive removal of toxic amaranth dye by alumina reinforced polystyrene (ARP) composite was studied as a function of contact time, pH, initial dye concentration, and temperature. The results indicated that adsorption was strongly dependent on pH and temperature of the dye solution. The adsorption was favored at low pH with the maximum removal at pH 2.0. Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) models were used for the description of adsorption equilibrium data and the best interpretation for the experimental data was given by the D-R model. The adsorption kinetics was tested using pseudo first order, pseudo second order, Elovich, intraparticle, and film diffusion models and the removal by ARP followed a pseudo second order kinetics. Thermodynamic studies revealed that both adsorption and desorption was spontaneous and endothermic in nature. From the exhausted adsorbent, about 70 and 96% desorption was obtained with (99%) CH3OH and 0.1M NaOH, respectively.