The performance of g-C3N4/biochar/nZVI in reducing nitrate in water
A g-C3N4/biochar(BC)/nanoscale zero-valent iron(nZVI)composite catalyst with deposited nZVI on the surface of g-C3N4/BC material was prepared.The physical and chemical properties,as well as the photoelectric performance of the prepared catalyst,were characterized using SEM,TEM,XPS,XRD,UV-Vis DRS,photocurrent test,etc.The nitrate(NO3-)reduction performance of g-C3N4/BC/nZVI under visible light irradiation was investigated.The results showed that the optimal reaction conditions in neutral water were a mass ratio of g-C3N4/BC to nZVI of 1∶0.6,an addition amount of g-C3N4/BC/nZVI of 2g/L and the initial NO3-concentration of 20mg/L.Compared with nZVI,BC/nZVI and g-C3N4/nZVI,g-C3N4/BC/nZVI exhibited the fastest NO3-reduction rate(k=10.6×10-2min-1)and higher denitrification efficiency(71.6%).The study further investigated the variation of nitrogen during the NO3-reduction by g-C3N4/BC/nZVI.The reduction mechanism is proposed that∶ Under visible light irradiation,photogenerated electrons transferred via BC to the surface of nZVI,which enhanced the reactivity and stability of nZVI,while BC material inhibited the oxidation of nZVI by photogenerated holes.The active electrons on the surface of nZVI reduced NO3-to N2 and NH4+,while the photogenerated holes further oxidized some NH4+ to N2 and other gaseous products.
万方数据
