Impacts of nanoparticles in water on biological nitrogen removals

[[abstract]]本研究探討六種不同奈米微粒（奈米氧化鋅、奈米銀、奈米氧化銅、奈米四氧化 三鐵、奈米二氧化鈦及奈米二氧化矽），對活性污泥脫氮機制之影響。實驗結果顯示奈米氧化鋅及奈米銀對脫氮反應之抑制效果最為明顯。8 mgl-1奈米氧化鋅對高污泥齡微生物硝化及脫硝抑制率分別為71.8及23.3%，2 mgl-1奈米氧化鋅對低污泥齡微生物硝化及脫硝抑制率分別為40.0及25.9%。而 8 mgl-1奈米銀對高污泥齡微生物硝化及脫硝抑制率分別為13.6及28.8%，對低污泥齡微生物抑制率則分別為20.4及22.4%。六種奈米微粒對好氧硝化的影響大於對缺氧脫硝的影響，抑制程度大小為奈米氧化鋅>奈米銀>奈米氧化銅>奈米四氧化三鐵>奈米二氧化鈦>奈米二氧化矽。研究亦發現奈米微粒對硝化脫硝反應的抑制，主要來自金屬離子的釋出及活性氧化物種(Reactive Oxygen Species, ROS)的生成，其釋出量與生成量隨奈米微粒濃度增加而增加。[[abstract]]This study explored the impacts of ZnO, Ag, Fe3O4, CuO, TiO2, SiO2 nanoparticles (NPs) on biological nitrogen removal. Experimental results showed that the inhibition of nitrogen removal by the presence of ZnO and Ag nanoparticles were higher than other nanoparticles. The abilities of nitrate and nitrite removal were inhibited by 71.8 and 23.3%, when 8 mgl-1 ZnO NPs added to the long sludge retention time (SRT) system. The abilities of nitrate and nitrite removal were inhibited by 40.0 and 25.9%, when 2 mgl-1 ZnO NPs added to the short SRT system,. The abilities of nitrate and nitrite removal were inhibited by 13.6 and 28.8%, when 8 mgl-1 Ag NPs added to the long SRT system, On the other side, the abilities of nitrate and nitrite removal were inhibited by 20.4 and 22.4%, when this added to the short SRT system. The order of the inhibition degree of nanoparticles for biological nitrogen removal was ZnO>Ag>CuO>Fe3O4>TiO2>SiO2. This study also found that the influence of nanoparticles on nitrification or denitrification process mainly resulted from the release of ionic metals and/or the formation of reactive oxidation species (ROS). The concentration of ionic metals and ROS increased with increasing nanoparticle concentration.[[note]]碩