改性TiO_(2)光催化膜处理贾鲁河河水效果

Water Treatment Effect of Jialu River by Modified TiO_(2) Photocatalytic Membrane

我国对地表水污染的大力治理已初见成效,但仍有一些地区(如我国中西部缺水地区)的地表水存在污染问题.缺水地区河道生态恢复缓慢,利用光催化膜对河水进行原位治理可辅助这类地区河道的综合整治.研究利用溶液流延法复合真空热处理法制得具有可见光活性的TiO_(2)光催化膜(N/C-TiO_(2)),利用扫描电镜表征光催化膜的形貌特征,通过其水处理效果评价其光催化性能.结果表明:①光催化膜材料表面暴露有TiO_(2)纳米颗粒团聚物,TiO_(2)纳米颗粒通过桥接成功生长在基体的表面,为催化剂在膜材料中的稳定性提供条件.②热处理温度对N/C-TiO_(2)膜光催化性能影响的试验结果表明,140℃热处理的N/C-TiO_(2)膜(140-N/C-TiO_(2)膜)的可见光催化活性优于120℃热处理的N/C-TiO_(2)膜(120-N/C-TiO_(2)膜),140-N/C-TiO_(2)膜在太阳光下对化学需氧量(COD_(Cr))的处理水平高达100%.③光催化膜在自然光照下对贾鲁河河水的处理应用结果表明,N/C-TiO_(2)膜在降低河水COD_(Cr)、NH 3-N和TP浓度方面优于P25 TiO_(2)膜,其中,N/C-TiO_(2)膜对COD_(Cr)和BOD_(5)的日平均去除率分别达50.0%和31.9%,COD_(Cr)/BOD_(5)(浓度之比)由0.246升至0.358.④膜循环利用试验结果表明,经多次循环使用,降解效率趋于稳定,仅降低了9.5%,说明该膜具有较好的重复利用性.研究显示,N/C-TiO_(2)膜光催化技术可作为优良的地表水处理的原位治理技术,可用于辅助缺水地区的河道治理工作,实现地表水水质的改善,具有较好的实际应用价值.

China has made great efforts to control surface water pollution,but there are still some surface waters pollution problems,such as the water-scarce areas in central and western China.Due to the slow ecological recovery of rivers in water-scarce areas,photocatalytic membrane can assist in the comprehensive improvement of rivers in such areas to realize in-situ river regulation.The visible light active photocatalytic membranes(N/C-TiO_(2))were prepared by solution casting approach and heating treatment in vacuum.The morphology of the membrane was characterized by scanning electron microscopy(SEM)and the photocatalytic performance of the membrane in water treatment was assessed.The results showed that a lot of TiO_(2) aggregated on the surface of the membrane material,showing irregular shapes.TiO_(2) nanoparticles successfully grew on the surface of matrix through bridging,providing a more stable connection between the catalyst and the membrane material.The effect of heat treatment temperature on photocatalytic performance of N/C-TiO_(2) film showed that the N/C-TiO_(2) membrane treated at 140℃(140-N/C-TiO_(2) membrane)exhibited better visible light-driven photocatalytic activity than the membrane sintered at 120℃(120-N/C-TiO_(2) membrane).The 140-N/C-TiO_(2) membrane exhibited outstanding treatment level of COD_(Cr) with up to 100%under sunlight.The application of membrane in the treatment of Jialu river water under natural light showed that N/C-TiO_(2)membrane was better than P25 TiO_(2) membrane in reducing COD_(Cr),NH 3-N and TP concentrations.Meanwhile,TiO_(2) membrane improved the biochemical characteristics of water.The average daily removal rate of COD_(Cr) and BOD_(5)by N/C-TiO_(2) film could reach 50.0%and 31.9%,respectively,and the ratio of COD_(Cr) to BOD_(5)(B/C)increased from 0.246 to 0.358.The membrane recycling test showed that the degradation rate of pollutants with N/C-TiO_(2) membrane increased with the increase of light intensity.After multiple cycles,the degradation efficiency tended to be stable and the degradation efficiency decreased by 9.5%,showing the high reusability of the membrane.This research shows that N/C-TiO_(2) membrane photocatalytic technology can be used as an excellent in-situ technology for surface water treatment to assist river management in water shortage areas and improve surface water quality,which has great potential for practical application.