Adsorption kinetics and equilibrium isotherms of cadmium removal from wastewater using Chlamydomonas reinhardtii immobilized in sodium alginate

Sodium alginate-immobilized Chlamydomonas reinhardtii (C. reinhardtii) can make the cells survive in harsh environments and its ability to remove cadmium from wastewater was investigated through a comparative study. Results showed that the entrapped beads displayed a higher capacity and efficiency for cadmium (Cd) removal, which was significantly affected by pH and cations. The maximum loading capacity of immobilized C. reinhardtii for Cd removal was 75.5±2.2 mg/g. The kinetic experiments showed that the process was very fast, with most of the adsorption occurring within 30 min of contact time and the equilibrium state was reached in about 120 min, and the kinetic behavior can be simulated by two models. The equilibrium data fitted well to Langmuir isotherms.