Removal of reactive textile dyes (Remazol Brillant Blue R and Remazol Yellow) by surfactant‐modified natural zeolite

In this study, surfactant‐modified zeolite (SMZ) was used to remove Remazol Brillant Blue R and Remazol Yellow reactive dyes from aqueous solutions. The influences of suspension pH, temperature, agitation rate, and the SMZ dosage on reactive dyes removal and adsorption capacity were investigated by conducting a series of batch adsorption experiments. The adsorption kinetics was tested for pseudo‐first‐order, pseudo‐second order, intraparticle diffusion model, Elovich, and Bangham models, and rate constants of the kinetic models were calculated. Equilibrium isotherms for the adsorption of reactive dyes were analyzed by the Freundlich, Langmuir, Dubinin–Radushkevich, and Tempkin isotherm models. The Langmuir monolayer adsorption capacities of Remazol Brillant Blue R and Remazol Yellow were estimated as 13.9 and 38.31 mg/g, respectively. The adsorption rate was rapid; more than half of the adsorbed Remazol Brillant Blue R was removed in the first 60 min and of Remazol Yellow in the first 30 min. Thermodynamic parameters such as ΔH 0 , ΔS 0 , and ΔG 0 , at 20°C, were found to be 5.2126 kJ/mol, 0.0273 kJ/mol K, and −2.7969 kJ/mol (Remazol Brillant Blue R), and 29.9747 kJ/mol, 0.10875 kJ/mol K, and −1.8900 kJ/mol (Remazol Yellow), respectively. © 2010 American Institute of Chemical Engineers Environ Prog, 2011