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In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst

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Journal of environmental sciences 2009年第7期21卷 985-990页

作者： HUANG Shaoyong, ZHANG Changbin, HE Hong research center for eco-environmental sciences, chinese academy of sciences, beijing 100085, china. research center for eco-environmental sciences Chinese Academy of Sciences Beijing 100085 China

An activated carbon （AC） supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H20 by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller （BET） analysis, scanning electron microscopy （SEM）, temperatureprogrammed desorption （TPD）, and temperature-programmed oxidation （TPO） were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.

关键词： in situ adsorption-catalysis Pd/AC volatile organic compounds

Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan,triclocarban and methyl-triclosan in aqueous samples

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science china Chemistry 2010年第12期53卷 2600-2607页

作者： GUO JieHong 1,2,LI XingHong 2,CAO XueLi 1,QU Lei 2,3,HOU DeKun 2 & XU XiaoBai 2 1 school of Chemical and environmental engineering,beijing technology and Business university,beijing 100048,china 2 State Key Laboratory of environmental Chemistry and eco-toxicology research center of eco-environmental sciences,chinese academy of sciences,beijing 100085,china 3 Zhengzhou university,Zhengzhou 450001,china school of Chemical and environmental engineering Beijing Technology and Business University Beijing China State Key Laboratory of environmental Chemistry and eco-toxicology research center of eco-environmental sciences Chinese Academy of Sciences Beijing China Zhengzhou university Zhengzhou China

As extraction solvents,ionic liquids have green *** this study,an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS),triclocarban (TCC) and methyl-triclosan (M-TCS) in water *** parameters that may affect extraction efficiencies were examined and optimized,including the types and amount of ionic liquids,volume of the diluent,heating temperature,cooling time,salt effect and pH *** the optimum conditions,linearity of the method was observed in the ranges of 0.0100-100 μgL-1 for TCS and M-TCS,and 0.00500-50.0 μgL-1 for TCC with correlation coefficients (r2) > *** limits of detection (LODs) ranged from 1.15 to 5.33 *** in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μgL-1,*** spiked recoveries of the three target compounds in reclaimed water,irrigating water,waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%,61.6%-87.8%,58.9%-74.9% and 64.9%-92.4%,*** with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS,TCC and M-TCS,this method is not only more environmentally friendly but also more sensitive.

关键词： ionic liquid temperature-controlled ionic liquid dispersive liquid phase microextraction UHPLC aqueous samples

Applications of synchrotron-based X-ray techniques in environmental science

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science china Chemistry 2010年第12期53卷 2529-2538页

作者： LUO Lei & ZHANG ShuZhen State Key Laboratory of environmental Chemistry and ecotoxicology research center for eco-environmental sciences,chinese academy of sciences,beijing 100085,china State Key Laboratory of environmental Chemistry and ecotoxicology research center for eco-environmental sciences Chinese Academy of Sciences Beijing China

Synchrotron-based X-ray techniques have been widely applied to the fields of environmental science due to their element-specific and nondestructive properties and unique spectral and spatial resolution *** techniques are capable of in situ investigating chemical speciation,microstructure and mapping of elements in question at the molecular or nanometer scale,and thus provide direct evidence for reaction mechanisms for various environmental *** this contribution,the applications of three types of the techniques commonly used in the fields of environmental research are reviewed,namely X-ray absorption spectroscopy (XAS),X-ray fluorescence (XRF) spectroscopy and scanning transmission X-ray microscopy (STXM).In particular,the recent advances of the techniques in china are elaborated,and a selection of the applied examples are provided in the field of environmental ***,the perspectives of synchrotron-based X-ray techniques are *** their great progress and wide application,the techniques have revolutionized our understanding of significant geo-and bio-chemical *** is anticipatable that synchrotron-based X-ray techniques will continue to play a significant role in the fields and significant advances will be obtained in decades ahead.

关键词： synchrotron spectroscopy spectromicroscopy environmental science

Effect of temperature on the sorption and desorption of perfluorooctane sulfonate on humic acid

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Journal of environmental sciences 2010年第3期22卷 355-361页

作者： Chengxia Jia, Chun You, Gang Pan State Key Laboratory of environmental Aquatic Chemistry, research center for eco-environmental sciences, chinese academy of sciences, beijing 100085, china. State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Sorption and desorption of perfluorooctane sulfonate （PFOS） on humic acid at different temperatures were studied. It was found that the sorption process could be modeled with power kinetic equation very well, suggesting that diflusion predominated the sorption of PFOS on the humic acid. The sorption capacity was doubled when the temperature increased from 5 to 35°C, and thermodynamics parameters △G0 was calculated to be –7.11 to –5.04 kJ/mol, △H0 was 14.2 kJ/mol, and △S 0 was 69.5 J/（mol·K）, indicating that the sorption was a spontaneous, endothermic, and entropy driven process. Desorption hysteresis occurred at all studied temperatures which suggested that humic acid may be an important sink of PFOS in the environment.

关键词： perfluorooctane sulfonate sorption desorption temperature humic acid

In situ DRIFTS study of hygroscopic behavior of mineral aerosol

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Journal of environmental sciences 2010年第4期22卷 555-560页

作者： Qingxin Ma,Hong He,Yongchun Liu State Key Laboratory of environmental Chemistry and ecotoxicology,research center for eco-environmental sciences,chinese academy of sciences,beijing 100085,china. State Key Laboratory of environmental Chemistry and ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

In situ diffusion reflectance infrared Fourier transform spectroscopy was used to study the water adsorption on mineral oxides （SiO2, a-Al2O3, MgO, Fe2O3, TiO2）. The results showed that all the water adsorption isotherms were well fitted with the Brunauer-Emmett-Teller （BET）-Ⅲ type equation, with the calculated monolayers occurring at 24%-30% relative humidity. It showed that about 1-5 layers of water adsorbed on oxides surfaces in ambient relative humidity （20%-90%）. The measured deliquescence relative humidity of NaCl was （74 ± 1）%, which demonstrated that DRIFTS is a useful method for the study the hygroscopic behavior of mineral dust. In addition, the limits of DRIPTS were also discussed.

关键词： DRIFTS mineral oxides water adsorption hygroscopicity

Soil carbon pool in china and its global significance

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Journal of environmental sciences 1996年第2期8卷 249-254页

作者： Fang Jingyun, Liu Guohua, Xu Songling(research center for eco-environmental science, chineseacademy of sciences, beijing 100085, china) Res. Ctr. for eco-Environ. science Chinese Academy of Sciences Beijing 100085 China

Soil organic carbon density and its related characteristics of 41 soil types all over china were analyzed by using data of 745 soil profiles , and size of soil carbon pool was estimated. As a result, area-weighted averages of these 41 soil types for bulk density, profile depth, organic carbon content and profile carbon were 1. 24 tC/m3, 86. 2 cm, 3. 04% and 19. 7 kg C/m2 respectively. Total size of soil carbon pool was 185. 68 × 1009tC, which is 29 times of that in terrestrial biomass of china and 12. 6% of global soil carbon pools. Because of its huge carbon pool, soil of china plays an important role in global carbon cycle.

关键词： china global climate change soil carbon content soil carbon pool soil type.

Combined fluorescence and electrochemical investigation on the binding interaction between organic acid and human serum albumin

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Journal of environmental sciences 2009年第3期21卷 373-379页

作者： CHEN Yan-Min,GUO Liang-Hong State Key Laboratory of environmental Chemistry and ecotoxicology,research center for eco-environmental sciences,chinese academy of sciences,beijing 100085,china. State Key Laboratory of environmental Chemistry and ecotoxicology Research Center for Eco-environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Human serum albumin （HSA） is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME （absorption, distribution, metabolism, and excretion） and bioavailability of the pollutants. The binding interaction between HSA and acetic acid （C2）, octanoic acid （C8） and dodecanoic acid （C12） has been investigated by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. For the study of the fatty acid interaction with the two drug-binding sites on HSA, two fluorescent probes, dansylamide and dansyl-L-proline were employed in the displacement measurements. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations from these three approaches were very similar. HSA did not show any change in the fluorescence and electrochemical experiments after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential mode, indicating an independent and non-cooperative binding. The calculated association constant and binding ratio were 3.1 × 10^6 L/mol and 1 with drug binding Site Ⅰ, 1.1 × 107 L/mol and 1 with Site Ⅱ, and 7.0× 0^4 L/mol and 4 with the tryptophan site, respectively. The measurements with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of the C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules.

关键词： absorption, distribution, metabolism, and excretion (ADME) organic acid human serum albumin fluorescence electrochemistry

Phosphorus release: A biogeochemical insight from a restored lakeside wetland in the Yangtze-Huaihe region, china

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Journal of environmental sciences 2010年第3期22卷 347-354页

作者： Xiaoling Zhou, Baoqing Shan, Hong Zhang State Key Laboratory of environmental Aquatic Chemistry, research center for eco-environmental sciences, chinese academy of sciences, beijing 100085, china. State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

The heavy intensification of agriculture in East china since the 1980s caused the decrease of lake area and water storage capacity with impediment of regulation, lake eutrophication and frequent floods. Many restoration projects have been conducted. However, the knowledge of biogeochemical factors that drive nutrient cycles during the early stage of restoration is still limited. We studied the effect of the remediation of a patch of near-shore shallow wetland on the northern bank of Chaohu Lake in the Yangtze-Huaihe region, china, which was used as rice paddy for many years, on the behavior of phosphorus. Redox potential （ORP）, temperature and dissolved oxygen were monitored in situ from May 2006 to November 2007. Samples of soil pore water were collected during this time for the determination of different forms of iron and phosphorus. ORP showed a clear transition of the wetland soil from an oxidized state in winter to a reduced state in summer. The decrease of ORP correlated with the release of large amounts of Fe and P. The maxima of total dissolved Fe and total dissolved P in the summer of the second year were （13.8 ± 6.8） mg/L and （0.88 ± 0.27） mg/L, respectively. It is worth noticing that P concentration far exceeded the critical value of lake eutrophication （0.02 mg/L）. The pressure of P release to the adjacent lake during the first two years of wetland restoration from rice fields should be taken into account by environmental policy makers.

关键词： wetland restoration phosphorus eutrophication redox potential iron

Determination of atmospheric concentrations of halocarbons in beijing area

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Journal of environmental sciences 1993年第1期5卷 76-82页

作者： Wang Shaobinresearch center for eco-environmental sciences, chinese academy of sciences, beijing 100085, chinaPeng Lixin and Tang Xiaoyanresearch center of environmental sciences, Peking university, beijing 100871, china research center for eco-environmental sciences Chinese Academy of Sciences Beijing 100085 China. China

Gas chromatography with ambient temperature injection and frozen-trapped techniques was used to determine the atmospheric concentrations of halocarbons over beijing. Halogenated compounds such as CFC-11, CFC-12, CHCl_3, CCl_4, CH_3CCl_3, CHCl =CCl_2, and CCl2=CCl2 were measured and their concentrations are 109±8, 234±13, 47±22, 97±24, 88±29, 11±1 and 17±3 (pptv), respectively.

关键词： GC-ECD atmospheric halocarbons beijing.