板钛矿TiO_(2)载体增强Mn-O-Ti相互作用及其对气态单质汞的吸附脱除促进机制  

Boosting Mn-O-Ti interaction by brookite TiO_(2) and its promotion mechanism of gaseous element mercury removal

作　　者：李鸿鹄 彭喜燕 安淼 揭翠 杨娇羽 李憬启 张敬东 曹艳晓[1,2] 杨俊 LI Honghu;PENG Xiyan;AN Miao;JIE Cui;YANG Jiaoyu;LI Jingqi;ZHANG Jingdong;CAO Yanxiao;YANG Jun(Research Center for Environment and Health,Zhongnan University of Economics and Law,Wuhan 430073;School of Information Engineering,Zhongnan University of Economics and Law,Wuhan 430073;Institute of Environmental Management and Policy,Zhongnan University of Economics and Law,Wuhan 430073)

机构地区：[1]中南财经政法大学环境与健康研究中心,武汉430073 [2]中南财经政法大学信息工程学院,武汉430073 [3]中南财经政法大学环境管理与政策研究中心,武汉430073

出　　处：《环境科学学报》2024年第12期317-327,共11页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.52100134);中南财经政法大学中央高校基本科研业务费专项资金(No.2722024EJ024);中国博士后科学基金面上项目(No.2022M721284)。

摘　　要：MnO_(x)/TiO_(2)是一种性能优异的气态单质汞(Hg^(0))吸附剂.制备方法、负载量、煅烧温度等因素对其Hg^(0)吸附性能的影响已被广泛研究.为进一步探明载体晶型对MnO_(x)/TiO_(2)的Hg^(0)吸附性能的影响,采用简单浸渍法在锐钛矿TiO_(2)(MnO_(x)/TiO_(2)-A)、金红石TiO_(2)(MnO_(x)/TiO_(2)-R)和板钛矿TiO_(2)(MnO_(x)/TiO_(2)-B)表面负载MnO_(x).通过固定床反应器测试3种MnO_(x)/TiO_(2)的Hg^(0)吸附效率及SO_(2)抗性.采用多种表征手段分析载体晶型对MnO_(x)/TiO_(2)金属氧化物-载体相互作用、Hg^(0)吸附性能和SO_(2)抗性的影响.研究发现,在相同烟气组分下,MnO_(x)/TiO_(2)-B的Hg^(0)吸附性能最为优异,100 min内Hg^(0)吸附效率维持在96%以上.通过拉曼(Raman)与X射线光电子能谱(XPS)等分析可知,MnO_(x)/TiO_(2)-B具有更强的金属氧化物-载体相互作用,其界面处形成的独特Mn-O-Ti结构,能够削弱Mn-O键强度,提高吸附剂表面氧物种的迁移率和缺陷氧含量,同时诱导高价态Mn(Mn^(4+))的形成,进而增强其对Hg^(0)的吸附氧化,促进表面HgO的生成.SO_(2)对3种晶型MnO_(x)/TiO_(2)的Hg^(0)吸附性能均存在抑制作用.其中,MnO_(x)/TiO_(2)-B和MnO_(x)/TiO_(2)-R抗硫性能稍弱,可能是由于其表面缺陷氧及-OH促进了SO_(2)的吸附氧化.本研究可为高Hg^(0)氧化活性锰基吸附剂的开发和改性提供理论依据.MnO_(x)/TiO_(2) is an excellent Hg^(0) adsorbent.The effects of preparation method,loading amount,calcination temperature and other factors on the Hg^(0) adsorption performance of MnO_(x)/TiO_(2) have been widely studied.In order to further investigate the influence of TiO_(2) crystal phase on the Hg^(0)adsorption performance,MnO_(x) was loaded on the surface of anatase TiO_(2)(MnO_(x)/TiO_(2)-A),rutile TiO_(2)(MnO_(x)/TiO_(2)-R)and brookite TiO_(2)(MnO_(x)/TiO_(2)-B)by simple impregnation method.The gaseous elemental mercury(Hg^(0))oxidation efficiency and SO_(2) resistance of MnO_(x)/TiO_(2) were tested in a fixed bed reactor.The effects of TiO_(2) crystal phase on the strong metal oxide-support interaction,Hg^(0) adsorption performance and SO_(2) resistance of the adsorbents were analyzed by various characterization methods.It was found that MnO_(x)/TiO_(2)-B had the most excellent Hg^(0) adsorption performance under the same flue gas conditions,with adsorption efficiency remaining above 96%within 100 min.According to the Raman and XPS results,MnO_(x)/TiO_(2)-B had the strongest metal oxide-support interaction.The unique Mn-O-Ti structure formed at the interface could weaken the strength of Mn-O bond and thus improve the mobility of oxygen species on the surface as well as the content of defect oxygen.The formation of hypervalent Mn(Mn^(4+))was also benefited from such interaction.The adsorption and oxidation capacity of Hg^(0) over MnO_(x)/TiO_(2)-B was thereby enhanced and the HgO product was more easily generated.SO_(2) could inhibit the mercury removal performance of the three MnO_(x)/TiO_(2) adsorbents.The SO_(2) resistance of MnO_(x)/TiO_(2)-B and MnO_(x)/TiO_(2)-R was relatively lower,which might be attributed to the surface oxygen defect and the surface-OH promoting the adsorption and oxidation of SO_(2).This study can provide a basis for the development and modification of high-performance Mn-based Hg^(0) adsorbents.

关 键 词：TiO_(2)载体晶型 金属氧化物-载体相互作用 缺陷氧 Hg^(0)吸附性能 SO_(2)抗性 

分 类 号：X511[环境科学与工程—环境工程]