Kinetic Studies of Heavy Metal Ion Sorption by Modified Oil Palm Waste Material

Abstract

Activated carbon adsorption has long been of beneficial use for numerous industries in order to achieve standard effluent discharge parameters. Owing to its high cost and difficult procurement of activated carbon, efforts are being directed towards finding efficient and low cost materials. Alternative utilization of oil palm waste materials, which is locally high in volume, is studied for adsorption of hexavalent chromium ion from aqueous solution simulating electroplating effluent. Simple chemical modification of oil palm waste materials has been made to enhance its adsorption capacity, thus preserving its economic value. Total removal of hexavalent chromium ions was achieved by oil palm fibre after being agitated for 2 hours under influence of acidic pH. Adsorption of chromium could be adequately described by both Freundlich and Langmuir isotherms. Kinetic studies were conducted using pseudo-first order and pseudosecond order kinetic models, yielding good R2 values from 0.9254 to 0.9870 and from 0.9936 to 0.9998 respectively. The analysis of variance (ANOVA) showed significant difference between the R2 values of the two models at 99 % confidence level.