Abstract:
This research was a study of the removal potential of paraquat from water by an adsorption process. Chemicals used in the experiments were bentonite from ICI Asiatic (Agriculture) , bentonite from Japan and galleon earth. Jar tests were performed under various controlling conditions of pH levels and at different clay concentrations. In all experiments, raw water was synthesized from a stock paraquat solution (without dye addition) to form blue colour and was preset to have constant paraquat concentrations of 100, 200, 300, 500, 1,000 and 2,000 ppm. It was found that pH was an insignificant parameter in controlling paraquat removal and the efficiency of paraquat removal varied as the clay concentration. The type of mineral in clay was an important parameter controlling the efficiency of paraquat removal. MontmorilIonite was the most suitable clay type for paraquat removal. Two different mechanism of paraquat removal were expected, i.e., cation exchange and adsorption, clay dosages for removal of paraquat with concentration of 100 , 300 and 500 ppm were 2,000, 3,000 and 6,000 mg/l, respeatively. The dosage for removing paraquat at the concentration over 500 ppm, was determined by using the removal capacity of 0.05 gram paraquat/gram clay. Activated carbon was most processing at low paraquat concentration, with removal capacity of 0.03 gram paraquat/gram activated carbon.