Electrochemical recovery of low concentration of palladium from palladium(II) chloride of electroplating wastewater

• Published in: Journal of chemical technology and biotechnology (1986) 2021-11, Vol.96 (11), p.3216-3223
• Main Authors: Mansor, Nadia, Mohamed, Norita, Mohd Suah, Faiz B
• Format: Article
• Language: English
• Subjects: Aluminum; batch reactor; Batch reactors; Cathodes; Chemical reactors; Chloride; Chlorides; Dilution; Electrochemistry; Electrode materials; Electrode polarization; electrogenerative process; Electroplating; Industrial wastewater; Low concentrations; Mass transport; Palladium; Plating; porous graphite; Qualitative analysis; Reactors; Recovery; reticulated vitreous carbon; Scanning electron microscopy; Spectroscopy; Stainless steel; Stainless steels; Sulfuric acid; Wastewater; Wastewater dilution
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.6878

BACKGROUND An electrochemical recovery of low concentration of palladium from a diluted palladium(II) chloride electroplating wastewater is presented. The electrochemical method used was an electrogenerative system which operated with a batch reactor. RESULTS A three‐dimensional cathode material of reticulated vitreous carbon (RVC) appeared to give the reactor less polarization compared to a three‐dimensional porous graphite and two‐dimensional stainless steel. Mass transport study confirmed RVC as the most suitable cathode in this electrogenerative system. The generated flow current of this system was supported by high performance of zinc as anode, compared to aluminium. Sulfuric acid served as the best cathode activation solution, having the highest recovery rate, with >90% of palladium being recovered in 5 h. Low concentrations of palladium(II) chloride solutions (100–500 mg L−1) were recovered at pH 5. Scanning electron microscopy–energy‐dispersive X‐ray spectroscopy was used for qualitative and quantitative analysis of deposited palladium on the cathode. It was shown that a pure metallic palladium deposits from chloride solution were obtained. Finally, the developed electrochemical reactor was also used to recover palladium from diluted electroplating wastewaters, and the results were satisfactory (>90% recovery). CONCLUSION This research shows that the electrogenerative system has the potential to recover palladium from diluted electroplating wastewaters.