Adsorption kinetics of a cationic dye from wastewater

The adsorption kinetics and thermodynamics of Maxilon Blue 5G, a cationic textile dye, onto perlite were investigated in aqueous solution in a batch system for determining the effect of contact time, stirring speed, initial dye concentration, initial solution pH, ionic strength and temperature. Experimental data were evaluated according to the pseudo-first, second-order and the Elovich equation, mass transfer and intra-particle diffusion models, and it was found that adsorption kinetics can be described according to the pseudo-second-order model, from which the rate constant and the adsorption capacity were determined. The thermodynamic activation parameters, such as activation energy, enthalpy, entropy and Gibbs free energy, were determined. The obtained results confirmed the applicability of this mineral as an efficient adsorbent for cationic dyes.