Recent trends in removal and recovery of heavy metals from wastewater by electrochemical technologies

Abstract

Heavy metal-laden water and wastewater pose a threat to biodiversity, including human health. Contaminated wastewater can be treated with several separation and purification methods. Among them, electrochemical treatment is a notable clean technology, versatile and environmentally compatible for the removal and recovery of inorganic pollutants from water and wastewater. Electrochemical technology provides solution for the recovery of metals in their most valuable state. This paper analyses the most recent electrochemical approaches for the removal and recovery of metal ions. Various current works involving cell design and electrode development were addressed in distinguished electrochemical processes, namely, electrodeposition, electrocoagulation, electroflotation, and electrosorption. Cathodic reduction of metal ions has been proven in result to metal deposit on the metal, metal oxide, stainless steel, and graphite electrode. However, little progress has been made toward electrode modification, particularly the cathode for the purpose of cathodic reduction and deposition. Meanwhile, emerging advanced materials, such as ionic liquids, have been presented to be prominent to the technological advancement of electrode modifications. It has been projected that by integrating different priorities into the design approach for electrochemical reactors and recent electrode developments, several insights can be obtained that will contribute toward the enhancement of the electrochemical process performance for the effective removal and recovery of heavy metals from water and wastewater in the near future.

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

“…When the competitive deposition was further carried out in the presence of silver, copper, and lead, the removal efficiency of lead (>80%) was much higher than the removal efficiency of copper (<20%), which was contrary to expectations based solely on reduction potentials ( Paul Chen and Lim, 2005 ). This result indicates that standard reduction potentials alone do not determine the composition of the deposit; other factors, such as metal concentration, pH, ionic strength, additives, the kind of substrate, chelating agents, mode of electrodeposition (chronoamperometry or chronopotentiometry), applied current signal, temperature, and fluid-dynamic conditions, all work together to determine the characteristics of deposition ( Banthia et al., 2017 ; Ibañez and Fatás, 2005 ; Kim et al., 2018a ; Maarof et al, 2017 ).…”

Conductive Polymer Composites from Renewable Resources: An Overview of Preparation, Properties, and Applications

“…That is to say, the selective electrochemical separation and extraction of copper in leachate can be realized by electrochemical metallurgy in theory. Researchers taking copper, nickel and other heavy metals as research objects and their sulfate solutions as simulated wastewater, systematically studied the effects of various factors in electrolysis on the current efficiency and recovery rate of metal deposition [ 56 , 57 , 58 ].…”

Performance-Based Selection of the Cathode Material for the Electrodeposition-Redox Replacement Process of Gold Recovery from Chloride Solutions

“…[16][17][18] Together with an acidic pH (below 2) and elevated temperatures, such solutions create an aggressive environment that requires exceptionally resistant materials. [19,20] Furthermore, during the EDRR process, the applied potential switches between cathodic and open circuit values, which makes the cathode more vulnerable for corrosion compared to traditional electrowinning.…”