Electrochemical Reduction Of Nitrate Via Cu/Ni Bimetal Composite Cathode Paired With Ir-Ru/Ti Anode

Groundwater as an important source of drinking water,its pollution problem caused by nitrate has increasingly become the focus of global attention.Nitrate pollution not only destroys water quality and environment,but also harms human health by drinking groundwater polluted by nitrate for a long time.Therefore,it is urgent to remove nitrate from water.Compared with other water treatment technologies,electrochemical technology has many advantages,such as simple operation,high efficiency,low investment cost,environmental friendliness and so on.Electrode material is very important for electrochemical reduction of nitrate,which determines the removal efficiency of nitrate.Therefore,the preparation of electrode materials with high catalytic reduction performance is the key to the study of nitrate removal in waterIn the course of this experimental research,a Cu/Ni bimetallic composite electrode was successfully prepared via a cathodic electrodeposition method and applied as a cathode material for nitrate removal from water.SEM,EDS,and XRD analysis results showed that Cu was successfully introduced on the surface of the Ni foam.Because of the increased number of catalytically active sites and decreased resistance of the electrode(as shown by LSV and EIS analysis),the Cu/Ni electrode exhibited dramatically superior activity for NO3--N removal(100.0%)within 60 min compared to the Ni electrode(15.0%).Furthermore,the optimization of electrode preparation and several factors influencing the electrolysis were discussed,allowing the following conclusions to be drawn:(1)Increased electrodeposition time(from 5 to 15 min)benefited electrode performance;electrodeposition for>15 min was not helpful.(2)Increasing the current density favored NO3--N removal as well as NO2--N and NH4+-N removal,yielding better TN removal.However,an excessively high current density reduced the electronic energy utilization efficiency;thus,25 mA cm-2 was the proper applied current density.(3)Cl-presence somewhat impeded NO3--N removal but significantly promoted NH4+-N removal.(4)Acidic conditions were detrimental to NO3--N and TN removal.In addition,reusability experiments were performed;the Cu/Ni electrode displayed excellent stability over eight reuse cycles.With increased reaction time,NO3--N was gradually completely converted to harmless N2 in the presence of Cl-.The Cu/Ni electrode showed good potential for large-scale NO3--N contamination remediation.