Application Trend of Heavy Metals in Electroplating Wastewater Treatment via Crystallization Technology

Heavy metal effluent generated during the electroplating process poses a considerable hazard to both the environment and human health. Traditional wastewater treatment technology has significant drawbacks, including lengthy process flows, low efficiency, high chemical consumption, high cost, resource loss, and a low percentage of water recycling. Crystallization technology has recently gained popularity among academics due to its high efficiency, low cost, minimal equipment requirements, and ease of use. This review had discussed the fundamental processes of crystallization, thermodynamic and kinetic concepts, and various crystallization technologies accessible. Then, the utilization of crystallization technology in copper, nickel, lead, iron, chromium, cobalt, and zinc is extensively discussed in terms of recycling heavy metals from electroplating effluent. The majority of researchers prefer fluidized bed crystallization technology, and it is noted that in the recovery process, it is preferable to recover compounds that can form stable, safe, and valuable compounds, such as lead carbonate formed during the treatment of lead plating wastewater. Finally, the review concluded by highlighting existing issues with crystallization technology and proposing potential future research and application directions to encourage the further development and enhancement of this technique in the field of electroplating wastewater treatment.