商用催化剂对氯代芳烃和氮氧化物的协同处置研究  

The research on the synergistic elimination of chlorinated aromatics and nitrogen oxides over commercial catalysts

作　　者：刘豪杰 李倩倩[2,3] 芦会杰 苏贵金 侯梅芳[1] 孙博华 吴明鸽 孟晶 史斌 LIU Haojie;LI Qianqian;LU Huijie;SU Guijin;HOU Meifang;SUNBohua;WU Mingge;MENG Jin;SHI Bin(School of Ecological Technology and Engineering,Shanghai Institute of Technology,Shanghai,201418,China;Key Laboratory of Environmental Nanotechnology and Health Effects,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China;University of Chinese Academy of Sciences,Beijing,100049,China;Beijing Municipal Institute of City Management,Beijing,100028,China)

机构地区：[1]上海应用技术大学生态技术与工程学院,上海201418 [2]中国科学院生态环境研究中心环境纳米技术与健康效应重点实验室,北京100085 [3]中国科学院大学,北京100049 [4]北京市城市管理研究院,北京100028

出　　处：《环境化学》2022年第4期1236-1251,共16页Environmental Chemistry

基　　金：国家重点研发计划(2020YFC1910100);国家自然科学基金(22006156,21876193);成都市科技项目(2018-ZM01-00019-SN)资助。

摘　　要：多污染物的协同控制是环境催化研究的前沿,氯代芳烃和氮氧化物(NO_(x))是生活垃圾焚烧等热工业过程中共存的典型污染物,目前商用催化剂能否实现二者的协同处置尚不清楚.因此,本文研究了5类商用SCR催化剂对氯苯(CB)和一氧化氮(NO)的协同处置活性.结果表明,1^(#)催化剂在300℃下对CB和NO具有较好的降解活性,且在90 min的反应周期内具有较高的稳定性,这是由于1^(#)催化剂具有较大比表面积、较高比例的表面吸附氧(O_(β))以及V^(5+).1^(#)催化剂对CB和NO的协同降解实验显示,在250℃和300℃下,NO的引入能够生成NO_(2),可促进CB的降解.300℃时CB的存在抑制了NO的转化,而当温度降到250℃时,CB对NO的转化有促进作用.这可能是因为在较高温度下NO_(2)生成量相对较多,C—Cl键解离程度较大,在一定程度上会影响SCR反应的进行,导致NO的转化率较低;而温度降低时,CO_(2)选择性增强,可能会抑制NH3的过度氧化,同时NO_(2)生成量和C—Cl键的解离均变弱,进而使得SCR反应相对增强.利用热脱附/GC-MS联用系统全面分析了降解过程中产生的中间产物,发现CB和NO协同处置体系中间产物种类显著减少,经过脱氯、烷基化、氧化等一系列反应生成苯、甲苯、苯甲醛和苯酚等中间产物,最终矿化生成H_(2)O和CO_(2).可见NO的引入不仅能促进CB的深度氧化,还能在一定程度上抑制多氯代副产物的生成.The synergistic control of various pollutants has attracted enormous interest in recent years.Both nitrogen oxides(NO_(x))and chlorinated aromatic hydrocarbon are typical pollutants coexisting in municipal solid waste incineration and other thermal industrial processes.However,it is unclear whether commercial catalysts can achieve the synergistic control of the NO_(x) and chlorinated aromatic hydrocarbon at present.Hence,the synergistic treatment of chlorobenzene(CB)and nitric oxide(NO)over five typical commercial catalysts at 250℃ and 300℃ was investigated in this study.The results indicated that 1^(#) catalyst exhibited the best degradation activity and excellent stability within 90 min reaction period,which was attributed to its larger specific surface area,higher proportion of surface-adsorbed oxygen(O_(β))and V^(5+).The synergistic elimination of CB and NO over 1^(#)catalyst demonstrated that the addition of NO could generate NO_(2) at 250℃ and 300℃,thus promoting the degradation of CB.In contrast,in the presence of CB,the conversion of NO was inhibited at 300℃ but was promoted as the temperature dropped to 250℃.Since at the condition of higher temperature,a large amount of NO_(2) was generated,and the C—Cl bond was greatly dissociated,which could affect the process of the SCR reaction,resulting in a lower conversion rate of NO.Nevertheless,as the temperature dropped,the enhancement of CO_(2) selectivity could inhibit the over-oxidation of NH3.Meanwhile,both the generation of NO_(2) and the dissociation of C—Cl were weakened,which in turn facilitated the SCR reaction.In addition,the intermediate products during the degradation process were comprehensively analyzed by thermal desorption/GC-MS.The results implied that the types of intermediate products in the synergistic control system of CB and NO were significantly reduced.A series of intermediate products such as benzene,toluene,benzaldehyde and phenol were generated via the reaction of dechlorination,alkylation and oxidation,and finally mi

关 键 词：商用催化剂 氯代芳烃 氮氧化物 催化氧化 协同降解 

分 类 号：X701[环境科学与工程—环境工程]