Removal of Atrazine from Aqueous Solutions Using HNO3 Treated Oil Palm Shell-Based Adsorbent
Activated carbon is a prominent material for adsorption of atrazine, however its usage is restricted due to the high cost. Thus, alternative adsorbent derived from agricultural waste has been investigated. This study focused on the feasibility of developing low-cost adsorbent from oil palm shell for removal of atrazine from aqueous solutions. The adsorbent was derived from oil palm shell using HNO3 treatment. The derived adsorbent was characterized for the surface morphology and surface chemistry using SEM and FTIR, respectively. Adsorption equilibrium experiments were carried out in batch mode to investigate the effects of adsorbent dosage, initial concentration, contact time and solution pH on the adsorption uptake of atrazine on the adsorbent. The Freundlich isotherm model showed a better correlation compared to Langmuir isotherm model to fit the equilibrium data, giving the adsorption capacity of 0.046 mg/g(l/mg)1/n at 30 oC. Atrazine solutions with pH 2 showed the highest adsorption uptake of 17.68%. The highest percentage removal was found to be 6.06% with adsorbent dosage of 2 g/200 ml. The adsorption process was found to follow the pseudo-second-order kinetic model more than the pseudo-first-order kinetic model as the correlation coefficients, R2 for the pseudo-second-order kinetic model were relatively higher for all atrazine concentrations, ranging from 0.878-0.999. The adsorbent derived was proven to be feasible in removing atrazine from aqueous solutions.