2025. Utilization of Response Surface Methodology to Optimize Ammoniacal Nitrogen Adsorption Efficiency from Palm Oil Mill Secondary Effluent Using Palm Empty Fruit Bunch as Adsorbent . Malaysian Journal of Fundamental and Applied Sciences. 21, 5 (Nov. 2025), 2538–2556. DOI:https://doi.org/10.11113/mjfas.v21n5.4326.