Abstract
Curcuma longa or turmeric was used as adsorbent for aluminium removal. The effects of operational factors, including pH, contact time and dose were studied, and their optimal controls were proven. Overall uptake of Curcuma longa was at the maximum when pH ranged between 5 and 9 and the optimal removal was 91.2%. Optimal removal of 95.8% was achieved at the 90th minute for the batch experiment. A dose of 6 g/L was enough for optimal removal of 93.6%. Aluminium adsorption onto Curcuma longa was found to have a good correlation with Freundlich adsorption model contrary to the Langmuir model. Simple kinetic model such as pseudo-first order, pseudo-second order, Elovich equation and intra-particulate mixing models were employed to determine the adsorption mechanism. The adsorption kinetic study showed that the pseudo-second order kinetic was the most applicable, and this result suggests that chemical adsorption process was more dominant.