表面电性对TiO_(2)纳米管-SiC复合填料去除养殖废水中氨氮效率的影响研究

Study on effect of surface electrical properties on removal efficiency of ammonia nitrogen from aquaculture wastewater by TiO_(2) nanotube-SiC composite filler

试验旨在探究二氧化钛(TiO_(2))纳米管-碳化硅(SiC)复合填料在净化养殖废水方面的性能。试验采用不同前驱体通过碱性水热合成方法合成3种不同粒径和晶相的TiO_(2)纳米管,测试了3种TiO_(2)纳米管的表面电性、X射线衍射图谱和场发射扫描电镜。研究TiO_(2)纳米管负载于SiC片上并覆盖微生物膜后,在紫外光照射和黑暗条件下去除养殖废水中氨氮污染物的性能。结果表明,晶相为锐钛矿的前驱体合成的TiO_(2)纳米管表面带负电,晶相为金红石和锐钛矿混合的前驱体合成的TiO_(2)纳米管表面带正电,而表面带正电的TiO_(2)纳米管能促进带生物负电的微生物的挂膜,进而促进对养殖废水中氨氮的去除作用;其中,负载P25 TiO_(2)纳米管的SiC片对氨氮的去除率在紫外光照射和黑暗条件下的去除率分别为86.1%和58.9%。研究表明,与黑暗条件相比,紫外光照射会影响TiO_(2)的光催化活性并提高TiO_(2)纳米管-SiC复合填料去除养殖废水中氨氮的效率。

The experiment was conducted to investigate the performance of titanium dioxide(TiO_(2))nanotube-silicon carbide(SiC)composite filler in purifying aquaculture wastewater.In this experiment,three kinds of TiO_(2) nanotubes with different particle sizes and crystal phases were synthesized by alkaline hydrothermal synthesis method with different precursors,the surface electrical properties,X-ray diffraction patterns and field emission scanning electron microscopy of the three TiO_(2) nanotubes were tested.The removal of ammonia nitrogen pollutants from aquaculture wastewater under ultraviolet irradiation and dark conditions was studied after it was loaded on SiC sheet and covered with microbial film.The results showed that the surface of TiO_(2) nanotubes synthesized by anatase precursor with crystal phase was negatively charged,while the surface of TiO_(2) nanotubes synthesized by rutile and anatase mixed precursor with crystal phase was positively charged,and TiO_(2) nanotubes with positive surface charge could promote the membrane adhesion of microorganisms with bionegative charge,thus promoting the removal of ammonia nitrogen in aquaculture wastewater.The removal rates of ammonia nitrogen in SiC sheet supported by P25 TiO_(2) nanotubes were 86.1%and 58.9%respectively under ultraviolet light and dark conditions.The results show that compared with dark conditions,UV irradiation can affect the photocatalytic activity of TiO_(2) and improve the efficiency of TiO_(2) nanotube-sic composite filler in removing ammonia nitrogen from aquaculture wastewater.