Adsorption of chromium from aqueous solution using treated oil palm fibre

Abstract

Chromium, being one of toxic heavy metals commonly found in various industrial wastewaters, is largely generated due to its widespread industrial applications; namely in steel and alloy making, electroplating, wood treatment, textile dyeing, paint production and leather tanning. Therefore, this study proposed an oil palm by-product as a lowcost adsorbent for the removal of trivalent chromium (Cr [III]) and hexavalent chromium (Cr [VI]) from aqueous solutions, simulating chromium-bearing wastewater. Adsorption of Cr (III) and Cr (VI) by the sulphuric acid and heat-treated oil palm fibre was conducted by separate batch process. The influence of pH, contact time, initial chromium concentration and adsorbent dosage on the removal of Cr (III) and Cr (VI) from the solutions was investigated. pH 5.0 and 1.5 were determined to be the optimum conditions for maximum uptake of Cr (III) and Cr(VI) from aqueous solutions respectively. The removal efficiency for both Cr species was found to correlate with the initial Cr concentration and adsorbent dosage as well as the contact time between Cr and the adsorbent. In the isotherm study, Cr (III) and Cr (VI) adsorption processes onto treated palm fibre were noted to conform to Freundlich Equation.