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

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 Pb 2+ , 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.