Copper chitosan complexes prepared by different specifications of chitosan and copper sulfate were used as urea sorbents. Experimental results showed that the adsorption capacity for urea of copper chitosan increased with an increasing degree of deacetylation and decreasing molecular weight of chitosan. The urea adsorption capacity of copper chitosan was 120.0 mg/g, when 1.0 g of copper chitosan was admitted to 100 mL of a 1300 mg/mL (pH 6-0) urea solution, with chitosan degree of deacetylation of 84.3% and viscosity molecular weight of 6.5 X 10(5), at 37degreesC for 8 h. No elution of the copper from the copper chitosan could be detected under the optimal conditions. (C) 2003 Wiley Periodicals, Inc.