LAUSR

Abstract In this work, the adsorption of Basic Blue 69 (BB69) and Acid Red 114 (AR114) dyes on cement kiln dust using batch technique was studied. The effects of contact time, mass of adsorbent and initial concentration of dyes were analyzed. Five kinetic models namely, pseudo first order, pseudo second order, Elovich, intraparticle diffusion, and Boyd were applied to analyze the experimental data. The data best fitted to pseudo second order and Elovich models indicating the chemical nature of the adsorption process. The maximum adsorption capacities of BB69 and AR114 were 2119 mg/g and 2125 mg/g, respectively. The equilibrium time was 240 min when using a dose of 8 g/L compared to 300 min when using a dose of 40 g/L. The adsorption rate was fast in the initial stage. Initial equilibrium was attained after 30 min when using a dose of 40 g/L and initial dye concentration of 500 mg/L. That value increased to 90 min when using the same adsorbent dose with initial dye concentration of 300 mg/L. Generally, the equilibrium was attained within 90–300 min depending on the dye, adsorbent dose, and initial dye concentration. The rate of adsorption was found to be affected by both film diffusion and intraparticle diffusion.