Removal of chromium and lead from drill cuttings using activated palm kernel shell and husk

Abstract

Palm kernel shell and Palm kernel husk, two readily available agricultural waste products have been used as low-cost potential adsorbents to remove chromium and lead from drill cuttings. Batch adsorption studies were carried out as a function of parameters such as pH, contact time and carbon dosage. Chromium and Lead removal was found to be pH dependent with the optimum pH for Chromium removal being 3 while that of Lead was 5 for both Activated carbon materials. Equilibrium time was attained at 90 min for the activated palm kernel shell and 120 min for the activated palm kernel husk. Maximum adsorption was attained at an adsorbent loading of 4 g. The equilibrium adsorption data obtained were measured with the Langmuir and Freundlich Isotherms and the experimental data were found to best fit the Freundlich isotherm model with R² = 91.947% for Cr with APKS, 86.39% for Cr with APKH, 89.37% for Pb with APKS and 96.74% for Pb with APKH. The intensity of adsorption for chromium was 1.3744 with APKS and 1.5511 with APKH while that for lead was 1.5087 with APKS and 1.6199 with APKH. The results show that a large proportion of Chromium and lead were adsorbed at low concentration of the adsorbate in solution and, therefore indicates a good potential for the application of agricultural wastes for heavy metal removal from drill cuttings.

Key words: Drill cuttings, heavy metals removal, palm kernel shell, adsorption.