Preparation Of RGO/(Fe+Cu)/CC Electrode And The Electrochemical Reduction Of Nitrate

Nitrate contamination in surface and ground waters is one of this century’s major engineering challenges.Nitrate pollution is regarded as one of the major chemical contaminants of surface and groundwater posing a severe threat to the ecosystem and human health.Aiming at this problem,many researchers have devoted themselves to the design of economical,efficient,stable,energy-saving,sustainable and clean nitrate disposal technologies,compared with the chemical reduction process,the electrochemical nitrate reduction technology has raised extensive attention due to its energy saving,simple operation,and environmental advantages.It has been noted that the electrode material is the key to the electrochemical reaction.Among them,transition metal iron is prominent due to its abundant reserves,low cost and high nitrogen selectivity,but the propertiesits of easy agglomeration and oxidation severely limit its engineering practice,so it is urgent to improved its catalytic activity via combining with copper which has good nitrate reduction ability.In this paper,the（Fe+Cu）/CC catalytic electrodes were prepared via liquid phase reduction method,and the techniques including X-ray diffraction（XRD）and scanning electron microscopy（SEM）were utilized to the characterize crystal composition and microstructure.The performances for nitrate reduction of（Fe+Cu）/CC electrodes were investigated under different operation parameters（the ratio of iron to copper,electrolysis time,initial p H,current density,and initial concentration）.Under optimal conditions（the initial concentration of NO₃^--N is 15 mg/L,p H is 7,and current density is 25 m A/cm²）,the nitrate removal rate and the nitrogen selectivity of（Fe+Cu）/CC electrode（Fe:Cu=1:15）is 92.3%and 24.4%,respectively,and the main product is ammonia nitrogen.Graphite oxide（GO）is characterized by a large number of active groups,high chemical activity and cost-effective,which can effectively improve the dispersion state of iron and copper nanoparticles and enhance electrode stability.In this work,GO was fabricated via the modified Hummers method,with which iron and copper particles was covered by means of suction filtration,after calcination,the r GO/（Fe+Cu）/CC electrode was obtained.The SEM,XRD,XPS and Raman described its microscopy,chemical compound and degree of carbonization in detail.Compared with（Fe+Cu）/CC,r GO/（Fe+Cu）/CC electrode behaves larger specific surface area and faster electron transfer rate by LSV,CV and EIS.Batch experiments were conducted under different parameters（the electrolysis time,initial p H value,current density,initial concentration and co-existing ion）,which showed that the r GO/（Fe+Cu）/CC system could achieve 94.2%nitrate removal rate and 72.4%N₂selectivity after 24 h reaction in the absence of chlorine,and the long-term stability was confirmed after 5 runs.Moreover,the potential application of r GO/（Fe+Cu）/CC electrode in nitrate wastewater treatment was preliminary investigated,and the results suggest that the electrode has a high practical engineering application value.