Abstract
A simple and convenient preparation method with high catalytic reduction activity is crucial for the remediation of nitrate contamination.In this study,the innovation for fabricating a nanoelectrode was developed by calcinating the anodized plate to alter the surface crystalline phase of the material.The prepared calcined Ti nanopores(TNPs)electrode could effectively remove up to 95.1％nitrate from simulated groundwater at 30 mA·cm-2 electrolysis for 90 min,while under the same conditions,the removal efficiency of nanoelectrode prepared by conventional methods was merely 52.5％.Scanning electron microscopy images indicated that the calcined TNP nanoelectrode was porous with different pore sizes.The higher nitrate removal efficiency of TNPs-500(95.1％)than TNPs-400(77.5％)and TNPs-550(93.4％)may resulted from the positive nonlinear response of the larger electrochemical active surface area,the improved electron transfer and suitable surface structure,and not the"anatase-to-rutile"of surface TiO2 nanotubes.After 90 min of electrolysis,using Ru02 as an anode and adding 0.3 g·L-1 NaCl solution,87.5％nitrate was removed,and the by-products(ammonia and nitrite)were negligible.Increased temperature and alkaline conditions can enhance the nitrate removal,while higher initial nitrate concentration only improved the nitrate removal slightly.Moreover,The TNPs-500 elec-trode also exhibited excellent nitrate removal performance in real groundwater with the efficiency at 82.9％and 92.1％after 90 and 120 min,which were 0.87(removal efficiency=95.1％),0.92(removal efficiency=100％)of the efficiency for simulated groundwater,indicating the widely applicable condi-tions of the TNPs-500 electrode.This approach of surface-bonded elements and structure modification through calcination significantly improves catalytic activity and will guide the simple designing of functional nanostructured electrodes with wide application conditions.
维普
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