Removal of cadmium from aqueous solution using low molecular weight chitosan derivative

A 23 factorial design was used to examine the sorption of Cd2+ onto cross-linked low molecular weight chitosan pyruvic acid derivative. Three factors and two levels of solution pH (A) (6.0 or 10.0), temperature (B) (45 or 70 °C) and Cd(II) concentration (C) (1 or 3 mg/L) were considered. Batch mode system was employed with 0.05 g of the sorbent and 25 mL of Cd(II) solution. The efficiency of cadmium removal during an exposition time of 4 h was then evaluated. The factors and their interaction effect on the cadmium removal efficiency followed the order: Cd(II) concentration > solution pH > interaction between solution pH and Cd(II) concentration > interaction between solution pH, temperature and Cd(II) concentration. Langmuir isotherm model was the best isotherm model. The Pseudo second order fitted well the kinetic data. The thermodynamic studies revealed the nature of the cadmium sorption.