Enhanced degradation of nitrate by a combined electrolysis precipitation process

Nitrate can be electrolyzed mainly into N₂, but the generated ammonia, as its secondary intermediate, is soluble and remained in the wastewater yet, which affects negatively the degradation of nitrate and total nitrogen. In this work, an electrolytic reactor constructed with Ti/RuSn anode and Fe cathode, was applied to electrolyze nitrate, and magnesium chloride was used as electrolyte and precipitant simultaneously, while disodium hydrogen phosphate (DSP) was added only as precipitant of ammonia. The results indicated that, most part of generated ammonia could be precipitated as magnesium ammonium phosphate (MAP) and some residual ammonia may be transformed into N₂ by breakpoint chlorination. Thus, the nitrate and total nitrogen (TN) degradation efficiencies could be enhanced obviously by the combined electrolysis precipitation process.