Ammonia nitrogen removal by zeolite and treated oil palm fibre

This research is a comparative study on the effectiveness of zeolite and an agricultural by-product (oil palm fibre) in ammonia nitrogen (NH3-N) removal from aqueous solution. Oil palm fibre was subjected to sulphuric acid and heat treatments to obtain the adsorbent. The removal of ammonia by zeolite and treated oil palm fibre was studied by conducting batch tests using an orbital shaker. The optimum initial pH for maximum uptake of NH3-N from aqueous solution was found to be 4.2 and 3.7 for zeolite and treated oil palm fibre respectively. The optimum contact time for both test materials was 2 h. The pseudo first order kinetic model yielded R2 values of 0.7315-0.9178 and 0.6903-0.8843 for zeolite and treated oil palm fibre respectively; whereas the pseudo second order kinetic model yielded better R2 values of 0.9907-0.9998 and 0.9761-0.9998 for zeolite and treated oil palm fibre respectively. Both Langmuir isotherm (R2 = 0.9836 for zeolite and 0.9563 for treated oil palm fibre) and Freundlich isotherm (R2 = 0.9567 for zeolite and 0.9349 for treated oil palm fibre) described NH3-N removal by the two materials very well. However, due to its higher adsorption capacity, treated oil palm fibre was found to be better than zeolite for NH3-N removal.