PERFORMANCE OF CADMIUM WASTEWATER TREATMENT BY ELECTRODEPOSITION

The effects of initial pH，initial concentration，current density and complexing agents on the recovery of cadmium were examined． The surface morphology of the deposition was tested by SEM． The phase analyses were obtained by X-ray diffractometer． Experimental results showed that cadmium removal efficiency in the solution reached 99. 3% as the pH 1. 5 ～ 3. 5． The kinetics constants went up with the increase of initial cadmium concentration． The largest deposited mass was produced at the deposition time of 90 min and the suitable current density of 4. 46 mA/cm2 ． Ammonia and cadmium forming complexes could promote the reaction rate of cadmium electrodeposition． Sediments of electrodeposition were tested by scanning electron microscopy ( SEM) and X-ray diffraction ( XrD ) ． SEM showed that the sediments of dendritic nanostructures． XrD showed that cadmium and cadmium hydroxide were existed mainly．