High N₂ selectivity was obtained by the employment of a novel two-step method to treat NO₃⁻-N containing wastewater. In this process, NO₃⁻-N was selectively reduced to NO₂⁻-N and NH₄⁺-N (molar ratio of 1:1) by Zn/Ag bimetallic material, and the produced NO₂⁻-N and NH₄⁺-N were further converted to N₂ gas at high temperature (210 °C) and high pressure (1.1 MPa). Batch experiments indicated that at Zn/Ag bimetallic reduction, the NO₃⁻-N reduction efficiency of 90.9% was obtained under the condition of temperature of 40 °C, Zn/Ag bimetal dosage of 60 g L⁻¹, reaction time of 30 min and the initial pH of 3.0. The optimal products molar ratio of the first reduction step was obtained by adjusting the experimental parameters (e.g. solution pH and reaction time) to achieve a satisfactory N₂ selectivity during the wet ammonia oxidation process, in which the maximum N₂ selectivity of 98.0% was achieved with 99.2% of NO₂⁻-N and 98.5% of NH₄⁺-N were removed, respectively. The two-step method was further applied in the NO₃⁻-N reduction from membrane filtration concentrate, and 84.9% of TN removal efficiency with the N₂ selectivity of 94.5% was obtained.

通过采用新型的两步法处理含NO ₃ ^-- N的废水，可以获得较高的N ₂选择性。在该方法中，通过Zn / Ag双金属材料将NO ₃ ^-- N选择性地还原为NO ₂ ^-- N和NH ₄ ⁺ -N（摩尔比为1：1），生成了NO ₂ ^-- N和NH _4。⁺ -N在高温（210°C）和高压（1.1 MPa）下进一步转化为N ₂气体。间歇实验表明，在锌/银双金属还原时，NO ₃ ^-在40℃的温度，Zn / Ag双金属剂量为60g L ^-1，反应时间为30分钟和初始pH为3.0的条件下，获得-N的还原效率为90.9％。通过调节实验参数（例如溶液的pH和反应时间）以获得湿氨氧化过程中令人满意的N ₂选择性，可以获得第一步还原的最佳产物摩尔比，其中最大N ₂选择性为98.0％。分别去除了99.2％的NO ₂ ^-- N和98.5％的NH ₄ ⁺ -N。两步法中的NO进一步施加₃ ^-从膜过滤浓缩物中减少-N，获得84.9％的TN去除效率，N ₂选择性为94.5％。