[In vitro adsorption of paraquat onto substituted chitosan beads].

Paraquat removal by chitosan with different substituents was investigated in vitro for evaluation of chitosan as a paraquat adsorbent in emergency treatment for acute paraquat poisoning. Chitosan CM and SU, in which the hydroxyl group at the C6 position is replaced by a carboxymethyl and sulfonic group, respectively, removed paraquat abundantly in purified water. However an inhibitory effect of sodium chloride on paraquat removal by CM and SU was recognized. On the other hand, paraquat removal by cross-linked chitosan (BCW) was accelerated in saline solutions. It was recognized that more paraquat was removed by BCW chitosan when the sodium chloride concentration was less than 1.8%. It was confirmed that some chitosan beads (CM and SU) could function as effective paraquat adsorbents through in vitro experiments.