Keywords: low cost adsorbents, waste activated sludge, palm oil mill effluent, ammonium adsorption, effluent treatment, kinetic modelling, thermodynamics, adsorption kinetics, wastewater treatment, ammonia
Adsorption of ammonium using waste activated sludge from palm oil mill effluent treatment plant
Low cost adsorbent was prepared using waste activated sludge (WAS) from a palm oil mill effluent (POME) treatment plant, and used to adsorb ammonium from aqueous solution. The effect of initial concentration, temperature, pH and adsorbent dose was studied in batch test to determine the kinetic and thermodynamic properties. The results showed that the uptake of ammonia increased with an increase in pH, initial concentration of ammonium and adsorbent dose but decrease with temperature. The adsorption of ammonium ion fitted both Langmuir and Freundlich isotherm. The highest monolayer saturation capacity of WAS was 37.07 mg/g at temperature 303oK. The −delta H show the process is exothermic while the amount of free energy (−delta G) indicate the adsorption were spontaneous and thermodynamically favourable. For kinetic model, pseudo second–order more suitable and significant in rate–controlling step in adsorption kinetic.