Research on Adsorption Performance of Chitosan-Activated Sludge Composite Adsorbent to Cadmium and Lead in Wastewater

The adsorption performance of the chitosan-activated sludge composite adsorbent on cadmium and lead in wastewater was examined, and the influencing factors, such as temperature, SCTS addition, pH, rotate speed and the concentration of heavy metals were investigated in a single factor experiment, thus the order of influencing factors and the optimal combination were determined in an orthogonal experiment. The results show that the factors affecting the adsorption of lead followed the order of pH > SCTS addition > initial concentration of Pb²⁺ > rotate speed. The optimal adsorption of Pb²⁺could be reached with the pH of 2, SCTS addition of 10 g·L^-1, Pb²⁺ initial concentration of 50 mg·L^-1, and rotate speed of 130 r·min^-1, and the removal rate of Pb²⁺ reached 95.76%. The factors influencing the adsorption of cadmium followed the order of pH > initial concentration of Cd²⁺ > rotate speed > SCTS addition. The optimal adsorption of Cd²⁺ could be reached with the pH of 2, SCTS addition of 2.5 g·L^-1, Cd²⁺ initial concentration of 60 mg·L^-1, and rotate speed of 130 r·min^-1, and the removal rate of Cd²⁺ reached 96.08%. The composite adsorbent explores a new way for reutilization of sludge and provides a new method for wastewater treatment.