Three-dimensional MoS2@GF cathode design based on substrate and boundary effects: Enhancement of bilayer capacitance and exposure of edge active sites for efficient mercury removal from wastewater

Mercury ions are present in water bodies through various processes and human activities, causing pollution to the environment and potential health risks to humans. In order to achieve the purification of mercury-containing wastewater and recycle of mercury resources, we designed a novel electrochemical reduction system to treat mercury-containing wastewater. MoS 2 @GF electrode was prepared by one-step solvothermal method. In the electrocatalytic reduction system MoS 2 @GF was the cathode and IrO 2 /Ti was the anode, and the reduction mechanism and optimal reaction conditions were investigated. The topological defects of GF can enable the uniformly distributed MoS 2 to expose a large number of S-vacancies, which can quickly utilize water molecules to produce H* with strong reductivity, and the anode produces ·O 2 − . These free radicals can efficiently and indirectly reduce Hg 2+ to Hg 0 . Under the conditions of voltage 2 V, electrode spacing 20 mm and stirring rate 200 r/min, the cathode achieves 96.3 % Hg 2+ removal efficiency for 50 mg/L HgSO 4 –10 % H 2 SO 4 solution in 0.5 h. The above research provides a novel method that can recover and utilize mercury resources efficiently and a thought for the application of electrochemical method to the treatment of heavy metal wastewater.