TiO_2 NRAs/CdS/Au复合薄膜光催化降解UDMH废水
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摘要
为降低偏二甲肼(UDMH)废水处理能耗、避免因使用添加剂等造成二次污染,制备了一种可见光响应的TiO_2纳米棒阵列(NRAs)/CdS/Au复合薄膜光催化剂。结果表明,TiO_2 NRAs/CdS/Au复合薄膜能够利用可见光降解UDMH,并且以模拟太阳光做光源时复合薄膜对UDMH的降解效果优于单纯可见光做光源时的效果。随UDMH初始浓度增加,其降解率降低,但总降解浓度上升;TiO_2 NRAs/CdS/Au复合薄膜光催化降解UDMH废水适宜的pH约为7.2;加入空穴捕获剂、羟基自由基捕获剂及鼓入氮气都降低UDMH降解率,而鼓入空气则会使UDMH的降解率提高。模拟太阳光和可见光分别照射时,TiO_2 NRAs/CdS/Au复合薄膜都能够对UDMH降解过程中产生的有毒物质亚硝基二甲胺(NDMA)和偏腙(FDMH)实施降解,但模拟太阳光下效果更好,鼓入臭氧有助于NDMA和FDMH的快速去除。
To reduce the energy consumption and avoid the secondary contaminants caused by the use of additives during unsym -metrical dimethylhydrazine(UDMH)wastewater treatment,a kind of TiO_2 nanorod array(NRAs)/CdS/Au thin film photocata-lyst with visible light response was prepared. Results show that TiO_2 NRAs/CdS/Au composite film can degrade UDMH using visi-ble light,and when using the simulated sun light as light source. the degrading effect of composite film on UDMH was better that of composite film on UDMH when using the pure visible light as light source. The degradation rate of UDMH decreases grad-ually along with the increase of initial concentration of UDMH,but the total degradation concentration increases. The suitable pH for the photocatalytic degradation of UDMH wastewater by TiO_2 NRAs/CdS/Au composite film is about 7.2. Addition of hole-capture scavenger,hydroxyl radical scavenger and pumping nitrogen gas all make the degradation rate of UDMH decrease,while pumping air makes the degradation rate of UDMH increase. The TiO_2 NRAs/CdS/Au composite film can degrade the toxic substances,nitrosyldimethylamine(NDMA)and formaldehyde dimethylhydrazone(FDMH),which are produced during the degradation of UDMH when the irradiation of simulated sunlight and visible light respectively,but the degradation effect of the simulated sunlight is better and pumping ozone can help the rapid removal of NDMA and FDMH.
To reduce the energy consumption and avoid the secondary contaminants caused by the use of additives during unsym -metrical dimethylhydrazine(UDMH)wastewater treatment,a kind of TiO_2 nanorod array(NRAs)/CdS/Au thin film photocata-lyst with visible light response was prepared. Results show that TiO_2 NRAs/CdS/Au composite film can degrade UDMH using visi-ble light,and when using the simulated sun light as light source. the degrading effect of composite film on UDMH was better that of composite film on UDMH when using the pure visible light as light source. The degradation rate of UDMH decreases grad-ually along with the increase of initial concentration of UDMH,but the total degradation concentration increases. The suitable pH for the photocatalytic degradation of UDMH wastewater by TiO_2 NRAs/CdS/Au composite film is about 7.2. Addition of hole-capture scavenger,hydroxyl radical scavenger and pumping nitrogen gas all make the degradation rate of UDMH decrease,while pumping air makes the degradation rate of UDMH increase. The TiO_2 NRAs/CdS/Au composite film can degrade the toxic substances,nitrosyldimethylamine(NDMA)and formaldehyde dimethylhydrazone(FDMH),which are produced during the degradation of UDMH when the irradiation of simulated sunlight and visible light respectively,but the degradation effect of the simulated sunlight is better and pumping ozone can help the rapid removal of NDMA and FDMH.
引文
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[3]GAO Xin,LIU Xiang-xuan,WANG Xuan-jun,et al.Photodeg-radation of unsymmetrical dimethylhydrazine by TiO2nanorod arrays decorated with CdS nanoparticles under visible light[J].Nanoscale Research Letters,2016,11:496-506.
[4]GAO Xin,LIU Xiang-xuan,ZHU Zuo-ming,et al.Enhanced visible light photocatalytic performance of CdS sensitized TiO2nanorod arrays decorated with Au nanoparticles as electron sinks[J].Scientific Reports,2017,4,973.
[5]Zyoud A H,Zaatar N,Saadeddin I,et al.CdS-sensitized TiO2in phenazopyridine photo-degradation:catalyst efficiency,sta-bility and feasibility assessment[J].Journal of Hazardous Materials,2010,173(1-3):318-325.
[6]Tang W Z,Huang C P.Photocatalyzed oxidation pathways of2,4-dichlorophenol by CdS in basic and acidic aqueous solu-tions[J].Water Research,1995,29(2):745-756.
[7]贾瑛,李毅,张秋禹.UV-Fenton方法处理偏二甲肼废水[J].含能材料,2009,17(3):365-368.JIA Ying,LI Yi,ZHANG Qiu-yu.Degradation of unsymmetri-aldimethy hydrazine wastewater by UV-Fenton process[J].Chinese Journal of Energetic Materials(Hanneng Cailiao),2009,17(3):365-368.
[8]Torabi A M,Ghiaee R.Decontamination of unsymmetrical di-methylhydrazine waste water by hydrodynamic cavitation-in-duced advanced Fenton process[J].Ultrasonics Sonochemistry,2015,23:257-265.
[9]PAN Jing-qiang,LI Xin-yong,ZHAO Qi-dong,et al.Construc-tion of Mn0.5Zn0.5Fe2O4modified TiO2nanotube array nano-composite electrodes and their photoelectrocatalytic perfor-mance in the degradation of 2,4-DCP[J].Journal of Materials Chemistry C,2015,3(23):6025-6034.
[10]Ryu J,Choi W.Effects of TiO2surface modifications on photo-catalytic oxidation of arsenite:the role of superoxides[J].Environmental Science&Technology,2004,38(10):2928-2933.
[11]JIN Shao-fen,LI Yuan-zhi,XIE Hao,et al.Highly selective photocatalytic and sensing properties of 2D-ordered dome films of nano titania and nano Ag2+doped titania[J].Journal of Materials Chemistry,2012,22(4):1469-1476.
[12]XU Bing-bing,CHEN Zhong-lin,FEI Qi,et al.Inhibiting the regeneration of N-nitrosodimethylamine in drinking water by UV photolysis combined with ozonation[J].Journal of Hazardous Materials,2009,168(1):108-114.
[13]咸琨,刘祥萱,王煊军.液体推进剂偏二甲肼氧化变质的规律和影响因素[J].火炸药学报,2006,29(5):39-41.XIAN Kun,LIU Xiang-xuan,WANG Xuan-jun.Investigation on characteristics and influencing factors of oxidation process of UDMH[J],Chinese Journal of Explosives&Propel lants,2006,29(5):39-41.
[14]徐亚飞.偏二甲肼与羟基自由基降解反应机理的理论研究[D].重庆:重庆大学,2008.XU Ya-fei.Theoretical study on the degradation mechanism of1,1-dimethylhydrazine and hydroxyl radical[D].Chongqing:Chongqing University,2008.
[15]王晓晨.偏二甲肼的臭氧紫外光降解研究[D].北京:清华大学,2008.WANG Xiao-chen.Degradation of unsymmetrical dimethylhy-drazine by O3/UV[D].Beijing:Tsinghua University,2008.