Chloride ion removal from Zinc sulfate aqueous solution by electrochemical method

Electrochemical method was carried out to remove chloride ions from zinc sulfate aqueous solution using a potentiostatic technique, and using copper sheets as a working electrode and an auxiliary electrode, Ag/AgCl electrode as a reference electrode. Chloride ion content was determined by chloride ion selective electrode measurement. SEM (scanning electron microscopy) was used to observe evolution of the chlorine species on the anode surface. EDS (energy dispersive spectrum), and XPS (X-ray photoelectron spectrum) were employed to characterize chemical composition of the anode surface after electrochemical dechlorination. Effects of anode potential vs Ag/AgCl reference electrode, ultrasonic agitation, reaction temperature and reaction time were investigated, and dechlorination mechanism was explored. The dechlorination process was highly dependent on anode potential, ultrasonic agitation and reaction time. For simulated zinc sulfate aqueous solution containing chlorine 300 mg·L− 1, dechlorination extent attained to 54.5% at 0.6 V anode potential, and ultrasonic agitation of 50 W for 3 h. The dechlorination reaction that produced CuCl(s) mainly occurred against the copper anode surface.

A schematic diagram of electrochemical dechlorination mechanism.Figure optionsDownload as PowerPoint slideHighlights
► Electrochemical method was used to remove chloride ions from zinc sulfate aqueous.
► Some parameters that influenced the dechlorination rate were studied.
► The dechlorination rate attained to 54.5%.
► It has good efficiency, easy operation and no emission of secondary pollutant.