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Size-dependent hydroxyl radicals generation induced by SiO_2 ultra-fine particles: The role of surface iron

Science china Chemistry 2009年第7期52卷 1033-1041页

作者： shang yu1, zhu tong1, li yi1,2 & zhao jincai3 1 college of environmental sciences and engineering, peking university, beijing 100871, china 2 Chinese Academy of Meteorological sciences, beijing 100871, china 3 Institute of Chemistry, Chinese Academy of sciences, beijing 100871, china college of environmental sciences and engineering Peking University Beijing China Chinese Academy of Meteorological sciences Beijing China Institute of Chemistry Chinese Academy of Sciences Beijing China

Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM10). The ultra-fine fraction of PM10 has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 14, 100, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 14 nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.812, p1). Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

关键词： ultra-fine particles nano-particles ·OH oxidative stress size-effect

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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 Jing 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,beijing 100871,china 2 college of Atmospheric Physics,Nanjing university of Information Science and Technology,Nanjing 210044,china State Key Joint Laboratory of environmental Simulation and Pollution Control college of environmental sciences and engineering Peking University Beijing China college of Atmospheric Physics Nanjing University of Information Science and Technology Nanjing 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 1.26 × 10-6 respectively under 0% and 20% relative humidity (RH) at NO 2 molecular concentration of 1.96 × 1015 mol/*** results showed that liquid water was formed at the site of MgCl2·6H2O,CaCl2·2H2O 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

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Network Pharmacology and Experimental Study of MomordicineⅠand MomordicineⅡfrom Bitter Melon Saponins in Inhibiting Fat Accumulation

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Biomedical and environmental sciences 2024年第5期37卷 526-530页

作者： HUANG Shi Ting li shang yuan li Xin yu zhu ying zhu lin ZHANG Jia Yan zhao Yan Sheng DAGliA Maria XIAO Xiang BAI Juan School of Food and Biological engineering Jiangsu UniversityZhenjiang 212013JiangsuChina Department of Pharmacy University of Napoli FedericoⅡVia D.Montesano 4980131 NaplesItaly International Research Center for Food Nutrition and Safety Jiangsu UniversityZhenjiang 212013JiangsuChina

Bitter melon(Momordica Charania L.),a member of the Cucurbitaceae family,is widely distributed across tropical and subtropical ***,an important functional component of bitter melon,has been proven to exert hypoglycemic effects similarly to insulin,and also possesses lipid-lowering properties inhibiting preadipocyte differentiation and fat synthesis^([1]).

关键词： melon Momordica subtropical

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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 Jing & zhao DeFeng State Key Joint Laboratory of environmental Simulation and Pollution Control college of environmental sciences and engineering,peking university,beijing 100871,china State Key Joint Laboratory of environmental Simulation and Pollution Control college of environmental sciences and engineering Peking University Beijing 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, A1203, 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-H2O, 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

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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 tong 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

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针铁矿改性生物炭对砷吸附性能

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环境科学 2019年第6期40卷 2773-2782页

作者：朱司航赵晶晶尹英杰商建英陈冲瞿婷中国农业大学资源与环境学院教育部植物-土壤相互作用重点实验室北京100193 中国农业大学资源与环境学院农业部华北耕地保育重点实验室北京100193

为了提高生物炭(BC)对砷的吸附能力,本研究选取小麦秸秆作为原料,采用共沉淀方法制备了针铁矿(Goethite)改性生物炭材料(Goethite@BC).比较了BC、Goethite和Goethite@BC对As(Ⅲ)的吸附特性,同时使用SEM-EDS、BET、FT-IR、XRD和XPS等技... 详细信息

为了提高生物炭(BC)对砷的吸附能力,本研究选取小麦秸秆作为原料,采用共沉淀方法制备了针铁矿(Goethite)改性生物炭材料(Goethite@BC).比较了BC、Goethite和Goethite@BC对As(Ⅲ)的吸附特性,同时使用SEM-EDS、BET、FT-IR、XRD和XPS等技术对改性吸附剂的理化性质和吸附机制进行表征.结果表明,扫描电子显微镜分析显示有纳米级针铁矿附着在生物炭表面,可有效提高生物炭的比表面积和总孔容; 3种吸附剂对As(Ⅲ)的吸附符合伪二级动力学模型和Langmuir等温吸附模型,Goethite@BC对As(Ⅲ)的最大吸附量为65. 20 mg·g^(-1),与BC相比吸附量提高了62. 10倍. Goethite@BC吸附机制包括非特异性吸附(静电引力)和特异性吸附(配位、络合、离子交换等),纳米针铁矿颗粒在Goethite@BC表面对污染物的吸附起到重要作用. Goethite@BC在污染物修复领域具有很好地应用前景.

关键词：生物炭(BC) 针铁矿改性砷(As) 吸附

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