Mono-/competitive adsorption of cadmium(II) and lead(II) using straw/bentonite-g-poly(acrylic acid-co-acrylamide) resin

摘要

We investigated the adsorption of Cd(2+)and Pb(2+)using straw/bentonite-g-poly(acrylic acid-co-acrylamide) resin as an adsorbent in single and binary-component systems. The resin was characterized by various analytical techniques. Adsorption experiments were conducted by varying the pH, adsorbent dosage, initial concentration and temperature. Adsorption data for Cd(2+)and Pb(2+)fitted the Langmuir isotherm in the single-component system. Kinetic data for Cd(2+)and Pb(2+)followed the pseudo-second-order kinetic in a single-component system. A maximum adsorption for Cd(2+)occurred at pH 5, whereas for Pb2+, the maximum Cd(2+)adsorption occurred at pH 3. The maximum Cd(2+)and Pb(2+)adsorption capacities were 315.1 mg g(-1)and 355.5 mg g(-1), respectively. In the binary-component system, the presence of Cd(2+)could improve the adsorption capacity of Pb(2+)and the presence of Pb(2+)could reduce the adsorption capacity of Cd(2+)when the Cd(2+)concentration was high. This study provides realistic and valid data on resin use to remove heavy metal ions from aqueous solutions.