TITLE:
Removal of Hexavalent Chromium from Aqueous Solution by Adsorption on Palm Oil Fuel Ash (POFA)
AUTHORS:
Nurulhana Nordin, Nur Amirah Ahmad Asmadi, Mohan Kumar Manikam, Azhar Abdul Halim, Marlia Mohd Hanafiah, Sarah Nadira Hurairah
KEYWORDS:
Hexavalent Chromium, Palm Oil Fuel Ash (POFA), Low Cost Adsorbent, Adsorption Isotherms, Adsorption Kinetics
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.8 No.2,
February
20,
2020
ABSTRACT: This study investigated the removal of hexavalent chromium, Cr(VI) from aqueous solution by adsorption using palm oil fuel ash (POFA), an agricultural waste from the palm oil industry. POFA adsorbent was characterized by X-ray diffraction (XRD) analysis. Batch adsorption study revealed that the optimum conditions for the removal were as follows: pH 2, adsorbent dosage 80 g/L and contact time of 6 min, which resulted in 92% removal and 0.464 mg/g maximum adsorption capacity. Adsorption isotherm and kinetic studies showed that Freundlich isotherm and pseudo-second-order kinetic models fitted best to the experimental data. Column adsorption study at 5 mL/min of flow rate showed that 90% removal was obtained at 2 min of contact time which represented its breakthrough point. The column reached saturation at 30 min and the maximum column adsorption capacity recorded was 0.412 mg/g. The column adsorption behavior showed good fit with both Thomas and Yoon-Nelson kinetic models. These findings suggested that the utilization of POFA as a low-cost adsorbent to remove Cr(VI) from wastewater, either in batch or fixed bed adsorption system is not only effective, but concurrently will help to reduce wastes from the palm oil industry.