Synthesis and use of esterified sawdusts bearing carboxyl group for removal of cadmium(II) from water

Summary

Improvement of the reaction of succinic anhydride with wood meal was studied in order to prepare low cost materials for the removal of heavy metals. Without solvent, the use of 1 equivalent of pyridine or triethylamine/succinic anhydride was necessary to obtain high grafting efficiencies at 80 °C. In the presence of small quantities of 1,2-dichloroethane as swelling agent, only 0.1 equivalent of catalyst was needed to obtain satisfactory results. Three more or less modified sawdusts were used after activation with NaHCO₃ for the removal of cadmium(II) from water. Metal binding capacity was directly connected with the acid value estimated by titration and can reach 200 mg/g. Strongly modified sawdust showed a cadmium binding capacity lower than expected because of diester formation.