KINETICS, EQUILIBRIUM AND THERMODYNAMICS STUDY ON THE ADSORPTION OF PB2+ IONS BY WATER HYACINTH POWDER FROM BOTH INDUSTRIAL WASTEWATER AND AQUEOUS SOLUTION

In this study, water hyacinth powder was an adsorbent for the removal of Pb2+ from an aqueous solution in batch. The individual adsorption capacity of Pb2+ by oven dried water hyacinth powder was studied. The study showed that the adsorption of Pb2+ is better described by the Langmuir isotherm model and the sorption capacity was found to be 16mg/g. Batch adsorption experiments were conducted were used to examine the effects of particle size, pH, contact time and adsorbent dosage on the removal of Pb2+ from aqueous solution by water hyacinth powder. The adsorption efficiency increased with pH and the optimum adsorption was observed at pH 4. Also, the adsorption efficiency of water hyacinth decreased with increase in particle size in the order: <300, >300<425, >425<2800 μm. The optimum time for adsorption of Pb2+ ions was 30 minutes while the optimal adsorption was obtained with 2.5g of the adsorbent. Assessment of kinetics studies showed that the removal of Pb2+ followed pseudo-first-order rate equations based on the coefficient of determination R2 values. The study showed that the use of water hyacinth powder in the removal of Pb2+ from aqueous solution is feasible.