UV/chlorine process for ammonia removal and disinfection by-product reduction: comparison with chlorination.
UV/chlorine process for ammonia removal and disinfection by-product reduction: comparison with chlorination.
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DOI：
10.1016/j.watres.2014.10.044
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发表时间：
2015
期刊：
影响因子：
12.8
通讯作者：
Xinran Zhang;Weiguang Li;E. R. Blatchley;Xiaoju Wang;Pengfei Ren
中科院分区：
文献类型：
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作者：
Xinran Zhang;Weiguang Li;E. R. Blatchley;Xiaoju Wang;Pengfei Ren
研究了波长为254 nm的紫外光照射与氯化(UV/氯工艺)联合应用对水处理中氨氮的去除效果。与断点氯化相比，UV/氯工艺具有更高的氨氮脱除率和更少的氯用量。在第一步反应中，NH3的氯化反应导致NH_2Cl的生成。NH_2Cl的光解和自由基氧化氨似乎是脱氨的主要途径。氨的三价氮被氧化，推测是通过与氨基自由基和氯自由基的反应。测量的产物包括NO3−和NO2−；很可能也产生了N2和N2O。此外，紫外线照射似乎改变了NOM对游离氯的反应能力。UV/氯工艺的氯用量较低，C-DBPs(THMS和HAAs)较少，但HANs较多。这些结果表明，UV/氯工艺可以替代传统的断点氯化处理含氨水，具有操作简单、反应时间短、化学药剂用量少等优点。
The combined application of UV irradiation at 254 nm and chlorination (UV/chlorine process) was investigated for ammonia removal in water treatment. The UV/chlorine process led to higher ammonia removal with less chlorine demand, as compared to breakpoint chlorination. Chlorination of NH3led to NH2Cl formation in the first step. The photolysis of NH2Cl and radical- mediated oxidation of ammonia appeared to represent the main pathways for ammonia removal. The trivalent nitrogen of ammonia was oxidized, presumably by reactions with aminyl radicals and chlorine radicals. Measured products included NO3−and NO2−; it is likely that N2and N2O were also generated. In addition, UV irradiation appeared to have altered the reactivity of NOM toward free chlorine. The UV/chlorine process had lower chlorine demand, less C-DBPs (THMs and HAAs), but more HANs than chlorination. These results indicate that the UV/chlorine process could represent an alternative to conventional breakpoint chlorination for ammonia-containing water, with several advantages in terms of simplicity, short reaction time, and reduced chemical dosage.