Development of advanced reduction process (ARP) of nitrate / nitrite by electrolysis with metallic iron

硝酸盐是封闭地表水系统和地下水中常见的污染物，通常会引起地表水系统严重的富营养化问题，对人体健康构成威胁。目前去除水中硝酸盐的技术包括生物反硝化、离子交换分离或反渗透和化学还原剂还原。近年来，硝酸盐的化学还原受到了广泛的关注。认为化学还原法对硝酸盐的去除率高于生物反硝化法。化学还原法对硝酸盐的选择性高于分离法。本研究的目的是开发一种电解方法，通过电解去除水中的硝酸盐作为氮气。在本研究中，金属铁作为还原剂用于水中硝酸盐的去除。实验研究了酸碱度对酸性和碱性好氧条件下硝酸盐还原速率和产物的影响。我们的研究清楚地表明，在酸性和好氧条件下，金属铁可以完全还原水中的硝酸盐。选择最佳的pH值可以控制硝酸盐的还原速率和产物。研究了以铂板为电极，亚铁离子和氯离子共存对硝酸电解还原的影响。实验结果表明，在反应溶液中加入亚铁离子后，硝酸根的电解还原效果明显增强。在反应溶液中加入亚铁离子和氯离子，硝酸完全转化为氮气。此外，还研究了铜离子和铁离子对电化学还原硝酸盐的影响。铜离子和亚铁离子能促进硝酸盐还原。铜离子对硝酸盐的还原效果明显优于亚铁离子。初始铜离子浓度和电流密度对硝酸盐还原有较大影响。少

Nitrate is a common pollutant in closed surface water systems and ground water, and it usually cause serious eutrophication problem in surface water systems and health threats to human. Current technologies to remove nitrate from water include biological denitrification, separation with ion exchange or reverse osmosis and reduction by chemical reductants. In recent years, the chemical reduction of nitrate has received a lot of attention. It is considered that chemical reduction processes of nitrate can achieve a higher removal rate of nitrate than biological denitrification processes. Furthermore, chemical reduction processes have a relatively higher selectivity for nitrate than the separating methods. The purpose of this study was to develop an electrolytic method to remove nitrate from water as nitrogen gas by electrolysis.In this study, metallic iron was used as a reductant for nitrate removal from water. The effect of pH on the reduction rate and products of nitrate under acidic an … More d aerobic conditions was experimentally studied. Our study clearly showed that nitrate in water can be completely reduced by metallic iron under acidic and aerobic conditions. Selecting an optimal pH value may control the reduction rate and products of nitrate.The effect of the co-existences of ferrous and chloride ions on electrolytic reduction of nitrate using platinum plate as the electrodes was investigated. The experimental results showed that the electrolytic reduction of nitrate was remarkably enhanced by the addition of ferrous ion in the reaction solution. Nitrate can be completely transformed to nitrogen gas with the additions of ferrous and chloride ions in reaction solution.In addition, effect of copper and iron ions on nitrate reduction with electrochemical method was investigated. Copper ion and ferrous ion can promote nitrate reduction. Copper ion is much more effective to nitrate reduction than ferrous ion. Initial copper ion concentration and current density have great influence on nitrate reduction. Less