Batch adsorption of activated coconut shell for the removal of zinc from palm oil mill effluent

Abstract

Activated carbon from coconut shell was prepared to investigate the removal of zinc from palm oil mill effluent (POME). The reduction of zinc is significant to protect the ecosystem. The effect of temperature on the adsorbent was observed from the thermo gravimetric analysis while the decomposition of the lignocellulosic structure of the adsorbent was observed at 385 ᵒC. A total mass loss of 38.87% was observed. The Fourier-transform infrared spectroscopy used for the chemical characterization illustrated that hydroxyl, carbonyl, ether and aromatic compounds were the major functional groups that contributed on the presence of oxygen at the available active sites on the adsorbent. This finding supported the result of the thermo gravimetric analysis of the lignocellulosic structure of the material. The adsorption equilibrium onto the coconut shell activated carbon was carried out to investigate the experimental data. The experimental data was fitted into the three isotherm models (Langmuir, Freundlich and Temkin) and from the findings, data was fitted most to the Temkin isotherm with a correlation coefficient of 0.9705. Adsorption efficiency of the activated coconut shell was obtained at 98.04%. This result explained the adsorbate –adsorbent interaction and the effect of heat energy on the adsorption process. The coconut shell activated carbon showed to be a very effective adsorbent for the removal of zinc from POME.