Mechanism and Modelling for Sorption of Toxic Ion on Cement Kiln Dust

Cement manufacturing is a critically important industry in Egypt. These industrial by-product and waste materials must be managed responsibly to insure a clean and safe environment. Cement kiln dust (CKD) is a significant by-product material of the cement manufacturing process. Cement kiln dust is a waste residue composed chiefly of oxidized, anhydrous, micron – sized particles generated as a by product of the manufacture of Portland cement. The use of cement kiln dust as adsorbent in wastewater treatment has a great attention as cheap material and clay structure. This work will discuss the basic characteristics of CKD physical and chemical properties and regulatory requirements. The batch removal of Cr(VI) from aqueous solution using lowcost adsorbents such as cement kiln dust under different experimental conditions. The influences of initial Cr (VI) ion concentration (20 to 300 mg·l1) and pH (1 to 4) were investigated in this study. Adsorption of Cr (VI) is highly pH-dependent and the results indicate that the optimum pH for the removal was found to be 1 for CKD. A comparison of kinetic models applied to the adsorption of Cr (VI) ions on the CKD was evaluated for the pseudo firstorder, the pseudo second-order, Elovich and intraparticle diffusion kinetic models, respectively. The results showed that the pseudo second-order kinetic model was found to correlate the experimental data well.