Ag/AgCl改性碳纳米管薄膜连续流光催化去除水中亚甲基蓝
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摘要
为了探究Ag/AgCl光催化薄膜在连续流状态下对有机污染物的光催化性能,采用连续沉积方法制备了Ag/AgCl改性碳纳米管(CNTs)薄膜,以亚甲基蓝为目标污染物,利用光化学过滤器对亚甲基蓝的光催化脱色效果进行了探究。结果表明,在900μW·cm-2光强下,Ag/AgCl-CNTs复合薄膜在连续流光催化体系中对10 mg·L-1的亚甲基蓝去除率可达90%,比传统序批式反应体系高出70%以上,说明连续流体系的对流传质效果明显优于序批式体系的扩散传质效果。同时,Ag/AgCl的沉积显著改善了CNTs薄膜的光催化脱色性能。在最佳实验条件下,Ag/AgCl改性后,复合薄膜的光催化脱色效果比CNTs薄膜提高了40%。Ag/AgCl-CNTs多功能复合薄膜体系具有光催化降解和膜分离以及减缓膜污染等多重特性。
To investigate the photocatalytic performance of Ag/AgCl photocatalytic filters towards organic pollutants degradation under continuous-flow conditions, the Ag/AgCl modified carbon nanotubes(CNTs) filters were preparedby using the sequential deposition method, and the photocatalytic decolorization effect of the photochemical filter was studied when methylene blue(MB) was taken as a model compound. The results showed that the MB removal efficiency could reach 90% for the Ag/AgCl-CNTs hybrid filters in a continuous-flow photocatalys is system towards 10 mg·L~(-1) MB solution at illumination intensity of 900 μW·cm~(-2), which was above 70% higher than that of conventional batch reactor. This indicated that the convection mass transfer effect in the former system was better than the diffusive mass transfer effect in the latter. Moreover, Ag/AgCl modification significantly improved the photocatalytic decolorization performance of Ag/AgCl-CNTs hybrid filters, and the decolorization efficiency of the hybrid filters was 40% higher than that of a CNT-alone filter under the optimal conditions. The Ag/AgCl-CNTs multifunctional composite filter system has multiple characteristics such as photocatalytic degradation,membrane separation and membrane fouling mitigation.
To investigate the photocatalytic performance of Ag/AgCl photocatalytic filters towards organic pollutants degradation under continuous-flow conditions, the Ag/AgCl modified carbon nanotubes(CNTs) filters were preparedby using the sequential deposition method, and the photocatalytic decolorization effect of the photochemical filter was studied when methylene blue(MB) was taken as a model compound. The results showed that the MB removal efficiency could reach 90% for the Ag/AgCl-CNTs hybrid filters in a continuous-flow photocatalys is system towards 10 mg·L~(-1) MB solution at illumination intensity of 900 μW·cm~(-2), which was above 70% higher than that of conventional batch reactor. This indicated that the convection mass transfer effect in the former system was better than the diffusive mass transfer effect in the latter. Moreover, Ag/AgCl modification significantly improved the photocatalytic decolorization performance of Ag/AgCl-CNTs hybrid filters, and the decolorization efficiency of the hybrid filters was 40% higher than that of a CNT-alone filter under the optimal conditions. The Ag/AgCl-CNTs multifunctional composite filter system has multiple characteristics such as photocatalytic degradation,membrane separation and membrane fouling mitigation.
引文
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[2] VOTSI N E P, KALLIMANIS A S, PANTIS D. An environmental index of noise and light pollution at EU by spatial correlation of quiet and unlit areas[J]. Environmental Pollution, 2017, 221(2):459-469.
[3] WU G, CAO W, LIU L, et al. Water pollution management in China:Recent incidents and proposed improvements[J]. Water Science&Technology, 2017, 18(2):603-611.
[4]刘梅红.印染废水处理技术研究进展[J].纺织学报, 2007, 28(1):116-121.
[5]洪俊明,洪华生,熊小京.生物法处理印染废水研究进展[J].现代化工, 2005, 25(7):98-110.
[6] LIU S, TANG Z R, SUN Y, et al. One-dimension-bassed spatially ordered architectures for solar energy conversion[J]. Chemical Society Reviews, 2015, 44(15):5053-5075.
[7] GAYA U L, ABDULLAH A H. Heterogeneous photocatalytic degradation of organic contaminants over titanium dioxide:A review of fundamentals, progress and problems[J]. Journal of Photochemistry and Photobiology C:Photochemistry Reviews,2008, 9(1):1-12.
[8]王欢,崔文权,韩炳旭,等. Ag/AgX(X=Cl,Br,I)等离子共振光催化剂的研究进展[J].化工进展,2013, 32(2):346-351.
[9] ZHANG H, FAN X, QUAN X, et al. Graphene sheets grafted Ag@AgCl hybrid with enhanced plasmonic photocatalytic activity under visible light[J]. Environmental Science&Technology, 2011, 45(13):5731-5736.
[10] SHI H, CHEN J, LI G, et al. Synthesis and characterization of novel plasmonic Ag/AgX-CNTs(X=Cl, Br, I)nanocomposite photocatalysts and synergetic degradation of organic pollutant under visible light[J]. ACS Applied Materials&Interfaces,2013, 5(15):6959-6967.
[11] JIANG Y, WANG W N, FORTNER J D, et al. Engineered crumpled graphene oxide nanocomposite membrane assemblies for advanced water treatment processes[J]. Environmental Science&Technology, 2015, 49(11):6846-6854.
[12] IIJIMA S. Helical microtubules of graphitic carbon[J]. Nature, 1991, 354(6348):56-58.
[13] GAO G, VECITIS C D. Electrocatalysis aqueous phenol with carbon nanotubes networks as anodes:Electrodes passivation and regeneration and prevention[J]. Electrochimica Acta, 2013, 98(10):131-138.
[14] LEE S M, LEE S C, KIM H J, et al. Pore characterization of multi-walled carbon nanotubes modified by KOH[J]. Chemical Physics Letters, 2005, 416(4):251-255.
[15] LIU Y, LIU H, ZHOU Z, et al. Degradation of the common aqueous antibiotic tetracycline using a carbon nanotube electrochemical filter[J]. Environmental Science&Technology, 2015, 49(13):7974-7980.
[16] WANG P, PROF B H, QIN X, et al. Ag@AgCl:A highly efficient and stable photocatalyst active under visible light[J]. Journal of the German Chemical Society, 2008, 47(41):7931-7933.
[17] TANG Y, SUBRAMANIAM V P, LAU T H, et al. In situ formation of large-scale Ag/AgCl nanoparticles on layered titanate honeycomb by gas phase reaction for visible light degradation of phenol solution[J]. Applied Catalysis B:Environmental,2011, 106(3/4):577-585.
[18] GAO G, PAN M, VECITIS C D. Effect of the oxidation approach on carbon nanotube surface functional groups and electrooxidative filtration performance[J]. Journal of Materials Chemistry A, 2015, 3(14):7575-7582.
[19] LIU H, VECITIS C D. Reactive transport mechanism for organic oxidation during electrochemical filtration:Mass-transfer,physical adsorption, and electron-transfer[J]. Journal of Physical Chemistry C, 2012, 116(1):374-383.
[20] CHEN C Y, JAFVERT C T. Photoreactivity of carboxylated single-walled carbon nanatubes in sunlight:Reactive oxygen species production in water[J]. Environmental Science&Technology, 2010, 44(17):6674-6679.
[21] ZHU Q, WANG W S, LIN L, et al. Facile synthesis of the novel Ag3VO4/AgBr/Ag plasmonic photocatalyst with enhanced photocatalytic activity and stability[J]. Journal of Physical Chemistry C, 2013, 117(11):5894-5900.
[22] CAI B, WANG J, GAN S, et al. A distinctive red Ag/AgCl photocatalyst with efficient photocatalytic oxidative and reductive activities[J]. Journal of Materials Chemistry A, 2014, 2(15):5280-5286.
[23] CHEN M L, ZHANG F J, OH W C. Synthesis, characterization, and photocatalytic analysis of CNT/TiO2 composites derived from MWCNTs and titanium sources[J]. New Carbon Materials, 2009, 24(2):159-166.