Removal of Fe(III), Mn(II) and Zn(II) from palm oil mill effluent (POME) by natural zeolite

The adsorption capacity of natural zeolite for the removal of heavy metal ions, zinc Zn(II), manganese Mn(II) and iron Fe(III), found in palm oil mill effluent was investigated in this study. The effects of contact time, agitation speed, pH, and sorbent dosage on the sorption of heavy metals were evaluated. The desorption potential of zeolite was also investigated. The sorption was fast with equilibrium reached within 180 min. The metal sorption increased with pH, and adsorption capacities ranged between 0.015 and 1.157 mg/g of zeolite. Equilibrium data followed the Langmuir isotherm model while the kinetic data were well described by the pseudo-second-order model. Maximum desorption was attained by HCl with 69.638, 58.575 and 61.516% of the initial adsorbed amount for Fe, Zn and Mn, respectively. More than 50% of Zn(II) and Mn(II) and about 60% of Fe(III) could be removed in the experiments. (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.