A selective and efficient chemical reduction of nitrate to nitrogen gas using micro-electrolysis on ZnAg combined with a photo-assisted reduction in the presence of formic acid was investigated. The 99.58% removal of nitrate, 0.073 min⁻¹ of rate constant and 94.3% nitrogen selectivity were achieved in Zn-Ag/hv/HCOOH system under the initial pH 2.5, 13.8 mmol/L of formic acid and 60 g/L of Zn-0.06%Ag dose at 60 min. The Zn-Ag/hv/HCOOH system had the highest removal rate and nitrogen selectivity for nitrate reduction compared with the alone or two combinations of ZnAg bimetals, formic acid, and UV-A. Furthermore, the co-existence anions of HCO₃⁻ and CO₃²⁻ showed a negative effect on nitrate reduction while SO₄²⁻ had slightly promoted the reduction process. During the nitrate reduction by Zn-Ag/hv/HCOOH process, rapid reduction of NO₃⁻ to NO₂⁻ was primarily caused by ZnAg bimetal. Subsequently, the conversion of NO₂⁻ to N₂ was mainly owing to the produced CO₂⁻ by the reaction of formic acid and UV-A. The results suggested a novel strategy of chemical reduction combined with photoreduction for denitrification with high reaction kinetic as well as high nitrogen gas selectivity.

研究了在甲酸存在下，通过在锌银上进行微电解与光辅助还原相结合的方法，将硝酸盐选择性有效地化学还原为氮气。在初始pH 2.5、13.8 mmol / L甲酸和60 g / L Zn的条件下，在Zn-Ag / hv / HCOOH体系中，硝酸盐的去除率为99.58％，速率常数为0.073 min ^-1，氮选择性为94.3％。 60分钟时-0.06％Ag剂量。与单独或两种Zn Ag双金属，甲酸和UV-A组合相比，Zn-Ag / hv / HCOOH系统具有最高的去除率和氮还原硝酸的氮选择性。此外，HCO的共存阴离子₃ ^-和CO ₃ ^2-对硝酸盐还原反应显示出负面影响，而SO ₄ ^2-则略微促进了还原过程。期间由锌-银/硝酸还原HV / HCOOH过程，快速还原NO ₃ ^-以NO ₂ ^-主要由锌引起的Ag的双金属。随后，NO转化₂ ^-至N ₂主要是由于所产生的CO ₂ ^-由甲酸和UV-A的反应。结果提出了一种新的化学还原与光还原相结合的新策略，该方法具有高的反应动力学以及高的氮气选择性，可以进行反硝化反应。