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The roles of heterogeneous chemical processes in the formation of an air pollution complex and gray haze

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Science China Chemistry 2011年第1期54卷 145-153页

作者： zhu tong,shang {2. & ZHAO defeng state key joint laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering,Peking University,Bei{2. 100871,China 1. state key {2. laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering Peking University Beijing 100871 China

Urban and regional air pollutions are characterized by high concentrations of secondary pollutants such as photo-oxidants （mainly ozone） and fine particulate matter, which are formed through chemical reactions of the primary pollutants emitted from various sources. The accumulation of these pollutants under stagnant meteorological conditions results in the formation of gray haze, reducing visibility and causing major impacts on human health and climate. In an air pollution complex, the co- existence of high concentrations of primary and secondary gaseous and particulate pollutants provides a large amount of reac- tants for heterogeneous reactions on the surface of fine particles; these reactions change the oxidizing capacity of the atmos- phere, as well as chemical compositions along with the physicochemical and optical properties of particulate matter, thereby accelerating formation of the air pollution complex and gray haze. Using in situ technologies, such as diffuse reflectance infra- red Fourier-transform spectroscopy and single-particle Raman spectroscopy, we systematically investigated the reaction kinet- ics and mechanisms of gaseous pollutants （i.e., NO2. SO2. 03, and formaldehyde） on the surfaces of the major components of atmospheric particles such as CaCO3, kaolinite, montmorillonite, NaC1, sea salt, A12.3, and Tit2. We found that the main re- action products were sulfate, nitrate, or formate, which can change the hygroscopicity and light extinction parameters of those particles significantly. By analyzing the reaction kinetics of these heterogeneous reactions, we identified synergetic mechanisms of the three ternary reaction systems, ,i.e., NOE-particles-H2., SO2.particles-O3, and organics/SO2.particles-UV illumination. These synergetic mechanisms can provide experimental and theoretical bases for understanding the feedback mechanisms and nonlinear processes in the formation of an air pollution complex and gray haze.

关键词： fine particles secondary pollutants oxidizing capacity ternary reaction nonlinear processes

Heterogeneous reactions of SO_2.on ZnO particle surfaces

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Science China Chemistry 2011年第1期54卷 161-166页

作者： LI Jia,shang jing & {2. state key joint laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering,Peking University,Beijing 100871,China 1. state key {2. laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering Peking University Beijing 100871 China

Heterogeneous reactions of SO2.on ZnO particle surfaces were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）. The influences of relative humidity （RH） and UV radiation （2. 365 nm） were investigated. In the absence of UV radiation, sulfite was the prominent product on the particle surfaces, and a negative relationship between RH and sulfite production was observed. In the presence of UV radiation, infrared （IR） absorption of sulfite and sulfate was evident in the spectra. With increasing RH or UV intensity, sulfite was gradually transformed into sulfate. UV intensity and RH exhibited a synergistic effect on the heterogeneous oxidation of SO2.on ZnO. On dry particles and with no UV radiation, the reaction order of SO2.on ZnO particles was 1.6. The initial uptake coefficient for the formation of sulfite, using the Brunauer-Emmett-Teller （BET） area as the reactive surface area of SO2. was 4.87 × 10^-6. At 40% RH and with UV radiation, the reaction order was 0.91, and the initial uptake coefficient was 2.2. ×10^-5.

关键词： SO2 ZnO DRIFTS heterogeneous oxidation UV radiation

Photocatalytic degradation of rhodamine B by dye-sensitized TiO_2.under visible-light irradiation

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Science China Chemistry 2011年第1期54卷 167-172页

作者： shang jing,ZHAO FengWei,{2. & LI Jia state key joint laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering,Peking University,Beijing 100871,China 1. state key {2. laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering Peking University Beijing 100871 China

Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light *** has been almost no study of the PTCDI-sensitized TiO2.composite used to photocatalytically degrade *** this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2.composites were prepared using a hydrothermal *** morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence *** visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model *** showed that dye-sensitized TiO2.samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2.*** double dye-sensitized (or co-sensitized) TiO2.composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2.*** electron transfer processes of single and double dye-sensitized TiO2.composites were illustrated according to band theory.

关键词： copper phthalocyanine tetrasulfonic acid dye sensitization perylene tetracarboxylic diimide rhodamine B visible-lightphotocatalysis

Heterogeneous reaction of formaldehyde on the surface of TiO_2.particles

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Science China Chemistry 2010年第12期53卷 2644-2651页

作者： XU BingYe 1,2.zhu tong 1,TANG XiaoYan 1 & shang {2. 1 1 state key joint laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering,Peking University,Bei{2. 100871,China 2.Zhejiang Province environmental Monitoring Center,Hangzhou 310012.China 1. state key {2. laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering Peking University Beijing 100871 China2. Zhejiang Province Environmental Monitoring Center Hangzhou 310012 China

The heterogeneous reaction of formaldehyde (HCHO) on the surface of titanium dioxide (TiO2. was investigated in situ using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) combined with ion chromatography (IC),X-ray diffraction (XRD),and transmission electron microscopy (TEM).Formate,dioxymethylene,methoxy,and polyoxymethylene were observed in the infrared spectra of TiO2.particles during the *** the surface of TiO2.the adsorbed HCHO was first oxidized to dioxymethylene and further oxidized to *** effects of temperature and ultraviolet radiation (UV) on the reaction products and reactive uptake coefficients were studied,and the results indicate that the reaction rate can be accelerated at increasing temperatures as well as under *** heterogeneous reaction mechanisms of HCHO on the surface of TiO2.in the dark and under UV irradiation are *** measurements show that formate formation on TiO2.is second order in HCHO concentration and the initial reactive uptake coefficients at room temperature calculated with the Brunauer-EmmettTeller specific surface area are (0.5-5) × 10-8 ([HCHO]:1 × 1013-2.× 10 14 molecules/cm3).A linear function relationship exists between the uptake coefficient and the *** apparent activation energy of the reaction was also determined.

关键词： DRIFTS formaldehyde heterogeneous reaction reactive uptake coefficient TiO2

Heterogeneous reaction of NO_2.with sea salt particles

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Science China Chemistry 2010年第12期53卷 2652-2656页

作者： YE ChunXiang 1,LI HongJun 1,zhu tong 1,shang {2. 1,ZHANG ZeFeng 1,2.& ZHAO defeng 1 1 state key joint laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering,Peking University,Bei{2. 100871,China 2.College of Atmospheric Physics,Nan{2. University of Information Science and Technology,Nan{2. 2.0044,China 1. state key {2. laboratory of environmental simulation and pollution control College of environmental Sciences and Engineering Peking University Beijing 100871 China2. College of Atmospheric Physics Nanjing University of Information Science and Technology Nanjing 210044 China

To understand how NO2.reacts with sea salt particles in the atmosphere of Mega-cities in coastal zones,the heterogeneous reaction of NO2.on the surface of wet sea salt was investigated with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Kinetic measurements indicated that nitrate formation on sea salt was second order in NO 2.concentration and reactive uptake coefficients were (5.51 ± 0.19) × 10-7 and 1.2. × 10-6 respectively under 0% and 2.% relative humidity (RH) at NO 2.molecular concentration of 1.96 × 1015 mol/*** results showed that liquid water was formed at the site of MgCl2.6H2.,CaCl2.2.2. on the surface of sea salt and made the reaction more sustainable by releasing hydrated water and absorbing water from air even under a low RH (30%).Therefore,pure NaCl particles should not be used to represent sea salt in studies of the heterogeneous reaction with NO2.

关键词： sea salt particles diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) hydrated water absorbed water reactive uptake coefficient

Heterogeneous reaction of NO_2.on the surface of montmorillonite particles

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Journal of environmental Sciences 2012年第10期24卷 1753-1758页

作者： Zefeng Zhang jing shang {2. zhu Hongjun Li defeng Zhao Yingju Liu Chunxiang Ye College of environmental Sciences and Engineering Peking UniversityBeijing 100871China CMA key laboratory for Atmospheric Physics and Environment Nanjing University of Information Science and TechnologyNanjing 210044China

The studies on heterogeneous reactions over montmorillonite, which is a typical 2.1 layered aluminosilicate, will benefit to the Understanding of heterogeneous reactions on clay minerals. Montmorillonite can be classified as sodium montmorillonite or calcium montmorillonite depending on the cation presented between the different layers. Using diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）, the heterogeneous reaction mechanism of NO2.on the surface of montmorillonite was firstly investigated. Results showed that the reaction of NO2.on the surface of sodium and calcium montmorillonite fit a first-order kinetics, and the reaction duration of calcium montmorillonite was longer than that of sodium montmorillonite under the dry condition. For either sodium or calcium montmorillonite, the uptake coefficient decreased as humidity increased.

关键词： heterogeneous reaction uptake coefficient DRIFTS montmorillonite NO2

Heterogeneous oxidation of SO_2.by O_3-aged black carbon and its dithiothreitol oxidative potential

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Journal of environmental Sciences 2015年第10期27卷 56-62页

作者： Weiwei Xu Qian Li jing shang Jia Liu Xiang Feng {2. zhu state key {2. laboratory of environmental simulation and pollution control College of Environmental Sciences and EngineeringPeking University POTEN Environment Group Co. Ltd.

Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2.in the atmosphere,leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2.was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. Combined with ion chromatography（IC）,DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2.oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of *** humidity or 2.4 nm UV（ultraviolet） light illumination enhanced the oxidation uptake of SO2.on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol（DTT） assay. The DTT activity over BC was decreased in the process of SO2.reduction, with the consumption of oxidative active sites.

关键词： Black carbon Ozone SO2.Heterogeneous reaction Oxidative potential Dithiothreitol assay

Comparison of light absorption and oxidative potential of biodiesel/diesel and chemicals/diesel blends soot particles

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Journal of environmental Sciences 2020年第1期32卷 184-193页

作者： Yu Kuang Yi Guo Jiaqi Chai jing shang Jiali {2. Svetlana Stevanovic Zoran Ristovski state key {2. laboratory of environmental simulation and pollution control College of Environmental Sciences and Engineeringand Center for Environment and HealthPeking UniversityBeijing 100871China International laboratoryfor Air Quality&Health(ILAQH) School of ChemistryPhysics and Mechanical EngineeringQueensland University of TechnologyBrisbaneQLD 4001Australia School of Engineering Faculty of Science Engineering&Built EnvironmentDe akin UniversityGeelong Waum Ponds CampusLocked Bag 20000GeelongVIC 3220Australia

Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health *** biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still *** watersoluble organic carbon(WSOC)content,surface chemical structure,light absorption and oxidative potential(OPDTT)of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT)*** differences and correlations between soot properties were statistically ***/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE)in2.0 and 365 nm(E2.E3),OPDTT,and higher surface carbonyl *** biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(ArC–O)content,and higher *** individual comparison of biodiesel/diesel blends showed2.%coconut biodiesel blend owned the lowest WSOC,E2.E3 and OPDTT,while highest ArC–O and MAE365,representing strongest absorbing *** analysis showed OPDTTwas significantly positively correlated with ***,the evident negative correlation between MAE365 and OPDTT was *** results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate ***,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel.

关键词： Soot particle Biodiesel Light absorption Mass absorbing efficiency Oxidative potential Dithiothreitol(DTT)

三维氧化石墨烯气凝胶高效吸附与可见光光催化去除六价铬

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科学通报 2022年第4期67卷 447-458页

作者：盛梦霜余梅尚静朱彤北京大学环境科学与工程学院环境模拟与污染控制国家重点联合实验室北京100871 北京大学工程科学与先进技术创新中心北京100080

三维气凝胶材料由于具有大比表面积和优异的光学、电学等性能,近年来引起研究者的关注.本研究以氧化石墨烯(graphene oxide,GO)为前驱体,结合交联法与超临界CO_(2.萃取法制备了三维多孔和易于回收的氧化石墨烯气凝胶(graphene oxide aer... 详细信息

三维气凝胶材料由于具有大比表面积和优异的光学、电学等性能,近年来引起研究者的关注.本研究以氧化石墨烯(graphene oxide,GO)为前驱体,结合交联法与超临界CO_(2.萃取法制备了三维多孔和易于回收的氧化石墨烯气凝胶(graphene oxide aerosol,GOA).采用扫描电子显微镜、X-射线衍射仪、拉曼光谱和氮气吸附法对其理化性质进行了表征,考察了其对于六价铬(Cr(Ⅵ))的吸附和可见光下的光催化还原性能.GOA制备过程中GO被水热还原且基面产生了较多缺陷,三聚氰胺与三聚氰酸作为交联剂增大层间距的同时使GOA拥有大比表面积和丰富的多孔结构.GO、三聚氰胺、三聚氰酸质量比为3:3:3且GO浓度为6 mg L^(-1)时,获得的样品GOA_(333-6)的比表面积和缺陷密度最大,且展现出对Cr(Ⅵ)最优的吸附能力和可见光光催化效率.GOA对Cr(Ⅵ)的吸附行为符合拟二阶动力学模型和Langmuir吸附等温模型,说明该吸附过程为单层的化学吸附,其中初始吸附阶段颗粒内扩散是限速步骤.本研究结合了吸附和光催化技术,制备出的GOA样品对于提高污染物去除效率和GO样品的开发利用都具有参考意义.

关键词：氧化石墨烯气凝胶六价铬光催化还原吸附动力学