Zongwei Wang’s research while affiliated with Huazhong Agricultural University and other places

Electrochemical technology is a widely employed technique for remediating soil contaminated with heavy metals. This technology can be utilized alone or in conjunction with other remediation techniques to improve the efficacy of heavy metals removal. The principle of electrochemical remediation technology involves utilization of electromigration, electroosmosis, and electrodialysis effects generated by an external electric field to transfer heavy metals from the soil to electrodes’ vicinity. However, this technology has not without limitations and challenges, including low permeability, pH gradient, soil composition, and heavy metal form, among other influencing factors. To overcome these obstacles, novel electrochemical coupling techniques have been proposed and developed, such as incorporating leaching agents, altering electrode materials or structures, employing pulse or alternating current sources. These technologies aim to increase the migration rate of heavy metals, decrease energy consumption, minimize by-products, and enhance the remediation effects. Among these, chemical leaching agents have garnered attention due to their outstanding treatment effects, simple technology, and ease of operation. Consequently, this paper first delineates the advantages of electrochemical technology and leaching technology over traditional adsorption passivation technology from the perspective of the removal mechanism. Secondly, the emphasis was placed on elucidating the technical principles of electrochemical technology and leaching techniques, as well as highlighting the drawbacks and limitations associated with their standalone application. Lastly, a remediation scheme for heavy metal-contaminated soil utilizing electrochemical coupling leaching technology is proposed. The practical significance of this work lies in the fact that electrochemical coupling leaching technology, compared to traditional adsorption passivation techniques, can greatly enhance the efficiency and effectiveness of heavy metal-contaminated soil remediation. It achieves the efficient, rapid, and thorough removal of heavy metal ions from the soil. Electrochemical coupling leaching technology speeds up the chemical leaching process that removes heavy metals from the soil, taking advantage of the best parts of both methods. The electric field then directs, aggregates, and deposits the released heavy metal ions onto electrodes, effectively separating them from the soil. This technology represents a thoroughly effective removal method, capable of avoiding the problem of secondary pollution caused by the re-release of heavy metal ions into the soil due to the changes in external environmental conditions. Therefore, research and application of electrochemical coupling leaching technology hold significant practical and scientific value.

Treatment of heavy-metal pollution in industrial wastewater is critical in protecting human health and the environment. Current methods for heavy-metal treatment have many limitations. For large quantities of industrial wastewater, the common methods such as adsorption and chemical precipitation can not meet the needs of actual production because of their high cost and limited removal efficiency.Electrochemical deposition is a rapidly developing clean treatment technology in recent years. The preparation of good electrode materials is one of the keys to the development of this technology. Firstly, by adjusting the pyrolysis temperature, rice straw was transformed into conductive biochar at 900 °C and CO2 atmosphere; then, we proposed a new concept of electrode preparation, that is, straw biochar electrode was prepared by thermosetting method. In this innovative method, a three-dimensional circular straw biochar electrode with high strength was successfully prepared by thermosetting method, phenolic resin as molding agent and conductive straw biochar as main raw material; using the electrode as cathode, cadmium polluted wastewater was treated by DC electrodeposition. The preliminary experimental results show that when the current density is 7.80mA/cm², the removal rate of cadmium in the solution reaches 76.60% in 240 min. Furthermore, the electrode is separated from cadmium by acid pickling to realize the effective recovery of cadmium and electrode regeneration. After regeneration, the removal rate of cadmium still reached 74.16%. Our work is very important for the treatment of cadmium ion pollution in water. The electrode can directly and effectively removes cadmium ions from wastewater. After pickling, the deposited cadmium can be effectively separated from the electrode, and the separated electrode can continue to be recycled. This study provides a simple and clean method for the treatment of cadmium containing wastewater, which can effectively reduce the cost of treating heavy metal wastewater by electrochemical deposition, and has important research and industrial significance.