低温等离子体协同Mn基催化剂降解氯苯研究

Degradation of chlorobenzene by non-thermal plasma with Mn based catalyst

以氯代挥发性有机物(CVOCs)中的典型代表氯苯为研究对象,分别采用硝酸锰(MN)和乙酸锰(MA)为前体,通过浸渍法制备Mn基催化剂,考察了低温等离子体协同Mn基催化剂降解氯苯性能以及抑制反应副产物臭氧生成的影响。研究发现对于不同反应系统,提升电压可以提高氯苯降解效率;催化剂引入能够大幅度提高氯苯降解性能,与MnO_(x)(MN)/γ-Al_(2)O_(3)相比,MnO_(x)(MA)/γ-Al_(2)O_(3)引入对氯苯降解效果更好,对臭氧生成的抑制性能更高。利用N_(2)吸附-脱附、扫描电镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)和X射线光电子能谱(XPS)等手段对反应前后催化剂进行表征分析,发现放电并未对催化剂的孔径及晶相结构产生影响;通过无机氯选择性和尾气质谱结果分析氯苯降解过程中氯元素变化;与MnO_(x)(MN)/γ-Al_(2)O_(3)催化剂相比,MnO_(x)(MA)/γ-Al_(2)O_(3)催化剂的比表面积相对较大,活性组分分散性更高、更均匀,从而导致反应系统内更多的臭氧在催化剂表面分解为活性氧原子,提高了氯苯的降解性能并抑制了反应系统内臭氧的生成。

Chlorobenzene(CB),a typical representative of chlorinated volatile organic compounds(CVOCs),was selected as the research object.Mn based catalysts were prepared by impregnation method with manganese nitrate(MN)and manganese acetate(MA)as precursors,respectively.The effects of non-thermal plasma cooperating with Mn based catalysts on the degradation of CB and the inhibition of ozone generation,a by-product of the reaction,were investigated.It is found that increasing the discharge voltage can improve the degradation efficiency of CB for different reaction systems.The introduction of catalyst can greatly improve the degradation performance of CB.Compared with MnO_(x)(MN)/γ-Al_(2)O_(3),the introduction of MnO_(x)(MA)/γ-Al_(2)O_(3) has better degradation effect and higher inhibition performance on ozone generation.The catalysts before and after the reaction were characterized by N_(2) adsorption-desorption,scanning electron microscope(SEM),X-ray diffraction(XRD),Fourier infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy(XPS).It was found that the discharge had no effect on the pore size and crystal structure of the catalyst.The variation of Cl elements during the degradation of CB were analyzed by Cl selectivity and tail GC-MS.Compared with MnO_(x)(MN)/γ-Al_(2)O_(3) catalyst,the specific surface area of the MnO_(x)(MA)/γ-Al_(2)O_(3) catalyst is relatively large,and the active components have higher and more uniform dispersion,resulting in more ozone of the reaction system being decomposed into active oxygen atoms on the catalyst surface,which improves the degradation performance of CB and inhibits the formation of ozone in the reaction system.