Preparation of Functionalized Palm Kernel Shell Bio-adsorbent for the treatment of heavy metal-contaminated water

Abstract

Human beings and living creatures are at great risk because of heavy metal contamination in water resulting from industrialization. On the other hand, millions of tons of palm kernel shells (PKS) and other oil palm wastes are produced every year from oil palm downstream industries. In this study, we attempt to consolidate both problems, where the PKS was oxidized with sulfuric acid for the formation of PKS-Sulfo, where the oxygenated and sulfonated functional groups are attached to the activated carbon. The resulting PKS-Sulfo bio-adsorbent was characterized in detail and was used for the treatment of heavy metal-contaminated water. Different adsorption parameters; pH, concentrations of metal ions, contact time, and adsorbent dosage were optimized. It was found that the PKS-Sulfo bio-adsorbent is highly efficient in adsorbing heavy metal ions; Cr6+, Pb2+, Cd2+, and Zn2+ from their aqueous water solutions. The adsorption process was found to follow the pseudo-second-order model and the Langmuir isotherm was better fitted compared to the Freundlich adsorption isotherm for the adsorption process of the heavy metal ions. Furthermore, the adsorption capacities were also determined for all the metal ions were found to be 99% for Cr6+ and Pb2+ and Cd2+ and Zn2+ was found to be 80 % and 70% respectively. This study opens up a new horizon for the preparation of functionalized bio-adsorbents with the potential for numerous applications, especially for water remediation.