Abstract
Adsorption of lead, copper and cadmium in solutions by roots of waterhyacinth were studied by batch and column methods using atomic absorption spectrophotometry (AAS). Lead, copper and cadmium were adsorbed to dry roots of waterhyacinth as rapidly as to fresh roots. This result suggested that metal adsorption by the roots was based on chemical action of some components contained in the roots, but not on physiological action. Maximum amounts of metals adsorbed by 1 gram of dry roots were 43 to 52×10-5 gram equivalent of lead, 48 to 53×10-5 gram equivalent of copper and 31 to 34×10-5 gram equivalent of cadmium from single metal solution. There was selectivity in adsorption by the roots. Lead was adsorbed most strongly among these 3 metals whereas cadmium was adsorbed most weakly. Metals adsorbed to the roots were eluted out completely with 0.1N hydrochloric acid, and adsorption ability of the roots was almost recovered. Therefore, the roots could be used repeatedly for the collection and removal of metals in solutions.
