Removal of Atrazine from Water Using Oil Palm Shell Based Adsorbents: Equilibrium and Kinetic Study

Abstract

Adsorption using granular activated carbon (GAC) in a permeable reactive barrier (PRB) has been proven in inhibiting the further spread of contaminant plumes in groundwater. GAC synthesized from oil palm shell was chosen for groundwater remediation in this study due to the low operation cost using the adsorption process. In this study, GAC synthesized from oil palm shells were used as adsorbent to adsorb atrazine from water. This study involved a series of batch experiment to determine the adsorption equilibrium and kinetics of adsorbent. The batch experiment was conducted by shaking conical flasks containing 0.6 g GAC in 300 mL solution with initial atrazine concentrations of 5, 10, 20 and 30 mg/L at 180 rpm at 30 ± 2 °C. The GAC showed more than 95 % of atrazine removal in all the batch experiments. The adsorption kinetic study showed that the adsorption of atrazine is of physisorption as the experimental data is fitted better to the pseudo-first-order model than the pseudo- second-ordermodel.Intheadsorptionisothermstudy,theadsorptionofatrazineontoGACwasbetterdescribedbytheFreundlich model which indicated multilayer adsorption on the heterogeneous surface of the adsorbent. The atrazine adsorption capacity of the GAC was 15.132 mg/g, which was higher than that using the activated carbon synthesized from waste charcoal (13.947 mg/g). ThisstudyshowsthatthereisapotentialforGACtobeusedforremediatinggroundwatercontaminatedbypesticides.