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Low temperature selective catalytic reduction of NO by C_3H_6 over Ce O_x loaded on AC treated by HNO_3

Journal of Rare Earths 2015年第4期33卷 371-381页

作者：楚英豪张腾腾郭家秀刘超尹华强朱晓帆刘勇军 College of Architecture and Environment Sichuan University National Engineering Technology Research center for Flue Gas Desulfurization Sichuan University sichuan provincial environmental Protection & environmental Catalytic Materials Engineering Technology center Sichuan University

The activated carbons from coal were treated by HNO3 （named as NAC） and used as carriers to load 7% Ce （named as Ce（0.07）/NAC） by impregnation method. The physical and chemical properties were investigated by thermogravimetric-differential thermal analysis （TG-DTA）, Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, scanning electron microscopy （SEM） and NH3-temperature programmed desorption （NH3-TPD） and NO-temperature programmed desorption techniques. The catalytic activities of Ce（0.07）/NAC were evaluated for the low temperature selective catalytic reduction （SCR） of NO with C3H6 using temperature-programmed reaction （TP-reaction） in NO, C3H6, 02 and N2 as a balance. The results showed that the specific surface area of Ce（0.07）/NAC was 850.8 m2/g and less than NAC, but Ce oxides could be dispersed highly on the acti- vated carbons. Ce oxides could change acid sites and NO adsorption as well as oxygen-containing functional groups of activated car- bons, and Ce4＋ and Ce〉 coexisted in catalysts. The conversion of NO with C3H6 achieved 70% at 280 ~C over Ce（0.07）/NAC, but with the increase of 02 concentration, heat accumulation and nonselective combustion were exacerbated, which could cause surface ashing and roughness, resulting in a sharp decrease of catalytic activities. The optimum 02 concentration used in the reaction system was 3% and achieved the high conversion of NO and the widest temperature window. The conversion of NO was closely related to the NO concentrations and [NO]/[C3H6] ratios, and the stoichiometric number was just close to 2：1, but the presence of H20 could af- fect the denitration efficiency of catalyst.

关键词： low temperature activated carbon cerium oxides selective catalytic reduction hydrocarbon rare earths

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Spatial-temporal Evolution Pattern of Agricultural Productivity in Northwestern sichuan Plateau

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Journal of Mountain Science 2013年第3期10卷 418-427页

作者： PENG Li SU Chun-jiang SUN Lian LI Ping FANG Yan LIU Wei WANG Xiao-lan Institute of Mountain Hazards and Environment Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences sichuan provincial environmental information center Southwest Jiaotong University sichuan Technology and Business College Institute of Horticulture Sichuan Academy of Agricultural Sciences

Currently, the agricultural growth in developed countries mainly relies on the improvement of productivity, which is also the target for China. Accordingly, the purpose of this study was to describe the spatial-temporal evolution pattern of agricultural productivity, to reveal changes in total factor productivity in 2ooo-2olo, and analyze the impact of these changes in northwestern sichuan plateau, China. Using data envelopment analysis （DEA） and the Malmquist Index, an in-depth study was conducted on agricultural productivity and changes in total factor productivity of 31 counties in northwestern sichuan plateau. Results indicated that：（1） geographically, counties with optimal efficiency were mainly located in the north of northwestern sichuan plateau and those with the lowest efficiency, in the south; （2） relative to pure technical efficiency, scale efficiency was the dominant factor in determining agricultural productivity; （3） the redundancy rate of input factors in zolo was slightly lower than that in zooo, thereby indicating an improved utilization of input factors to a certain extent and a great potential for further improving such utilization; （4） during the 2ooo-2olo period, the agricultural total factor productivity had an average annual growth rate of 8.3%, but the growth rates in various regions differed widely; （5） technical progress was the dominant factor promoting the improvement of total factor oroductivitv inagriculture. The disparities in spatial distribution may be due to the differences of natural conditions, former level agricultural productivity between counties. The findings are valuable for the government to make sustainable development policies for agriculture and improving agricultural development in northwestern sichuan plateau.

关键词： Agricultural Productivity Spatial-temporal evolution DEA Malmquist sichuanplateau

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Unveiling H_(2)O_(2)-optimized NO_x adsorption-selective catalytic reduction(AdSCR)performance of WO_(3)/CeZrO_(2) catalyst

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Rare Metals 2023年第11期42卷 3755-3765页

作者： Yan Huang Shuang Liu Ming-Ming Pei Jia-Yi Li Hai-Di Xu Yao-Qiang Chen Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu610064China Key Laboratory of Green Chemistry and Technology College of ChemistrySichuan UniversityMinistry of EducationChengdu610064China sichuan provincial Automobile Exhaust Purification Engineering Technology Research center Chengdu610064China sichuan provincial environmental Protection environmental Catalytic Materials Engineering Technology center Chengdu610064China

Recently,NO_x emissions in the cold-start period have been a great challenge in eliminating diesel vehicle *** this study,a type of NO_x adsorption-selective catalytic reduction(AdSCR)bifunctional catalyst was developed to remove NO_x in the cold-start period by constructing additional NO_x adsorption sites on the surface of the selective catalytic reduction of NO_x with NH_(3) *** AdSCR catalyst exhibited both NO_x adsorption-storage performance and NH_(3)-SCR *** amount of oxygen vacancies directly affected the adsorption performance of NO_x on the catalyst *** this study,H_(2)O_(2)with different pH values was employed to adjust the electronic structure of the CeZrO_(2) support and construct oxygen vacancies on the surface of CeZrO_(2),which contributed to improving NO_x adsorption and storage on the WO_(3)/CeZrO_(2)(W/CZ)catalyst below 200℃.The catalytic performance results show that CZ supports modified by alkaline H_(2)O_(2) rather than acidic and neutral H_(2)O_(2) significantly improve the NO_x adsorption capacity without decreasing the NH3-SCR *** characterization results show that the CZ support modified by alkaline H_(2)O_(2)possesses more surface oxygen vacancies and chemisorbed oxygen than CZ supports modified by acidic and neutral H_(2)O_(2).Oxygen vacancies are not only the active sites of NH_(3)-SCR,but also the active sites of NO_x ***,the W/CZ catalyst modified by alkaline H_(2)O_(2)exhibited an excellent AdSCR *** study proposes a novel perspective to address the issue of NO_x emissions from diesel vehicles during the cold start period.

关键词： NO_x adsorption Oxygen vacancy CeZrO_(2) Electronic structure Redox property

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Seasonal variations of transport pathways and potential sources of PM2.5 in Chengdu, China （2012-2013）

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Frontiers of environmental Science & Engineering 2018年第1期12卷 137-147页

作者： Yuan Chen Shaodong Xie Bin Luo School of Safety and environmental Engineering Capital University of Economics and Business Beijing 100070 China College of environmental Sciences and Engineering Peking University Beijing 100871 China sichuan provincial environmental Monitoring center Chengdu 610041 China

Seasonal pattem of transport pathways and potential sources of PM2.5 in Chengdu during 2012 2013 were investigated based on hourly PM2.5 data, backward trajectories, clustering analysis, potential source contribution function （PSCF）, and concentration-weighted trajectory （CWT） method. The annual hourly mean PM2.5 concentration in Chengdu was 97.4 μg. rn . 5, 5, 5 and 3 mean clusters were generated in four seasons, respectively. Short-distance air masses, which travelled within the sichuan Basin with no specific source direction and relatively high PM2.5 loadings （〉80 μg.m 3） appeared as important pathways in all seasons. These short pathways indicated that emissions from both local and surrounding regions of Chengdu contributed significantly to PM2.5 pollution. The cities in southern Chengdu were major potential sources with PSCF〉0.6 and CWT〉90 /g.m-3.

关键词： Transport pathwayBackward trajectoryClustering analysisPotential sourceChengdu

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Structural Variation of an Atmospheric Heat Source over the Qinghai-Xizang Plateau and Its Influence on Precipitation in Northwest China

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Advances in Atmospheric Sciences 2009年第5期26卷 1027-1041页

作者：魏娜巩远发何金海 Shaanxi provincial Climate center center for Plateau Atmospheric and environmental Research Department of Atmospheric Science Chengdu University of Information Technology College of Atmosphere Sciences Nanjing University of Information Science and Technology

NCEP/NCAR reanalysis data and a 47-year precipitation dataset are utilized to analyze the relationship between an atmospheric heat source （hereafter called 〈 Q1 〉） over the Qinghai-Xizang Plateau （QXP） and its surrounding area and precipitation in northwest China. Our main conclusions are as follows：（1） The horizontal distribution of 〈 Q1 〉 and its changing trend are dramatic over QXP in the summer. There are three strong centers of 〈 Q1 〉 over the south side of QXP with obvious differences in the amount of yearly precipitation and the number of heat sinks predominate in the arid and semi-arid regions of northwest China （NWC）, beside the northern QXP with an obvious higher intensity in years with less precipitation. （2） In the summer, the variation of the heat source＇s vertical structure is obviously different between greater and lesser precipitation years in eastern northwest China （ENWC）. The narrow heat sink belt forms between the northeast QXP and the southwestern part of Lake Baikal. In July and August of greater precipitation years, the heating center of the eastern QXP stays nearly over 35°N, and at 400 hPa of the eastern QXP, the strong upward motion of the heating center constructs a closed secondary vertical circulation cell over the northeast QXP （40~ 46~N）, which is propitious to add precipitation over the ENWC. Otherwise, the heating center shifts to the south of 30°N and disappears in July and August of lesser precipitation years, an opposite secondary circulation cell forms over the northeast QXP, which is a disadvantage for precipitation. Meanwhile, the secondary circulation cell in years with more or less precipitation over the ENWC is also related to the heat source over the Lake Baikal. （3） The vertical structure of the heat source over the western QXP has obvious differences between greater and lesser precipitation years in western northwest China in June and July. The strong/weak heat source over the western QXP produces relatively strong/weak

关键词： Qinghai-Xizang Plateau atmospheric heat source/sink greater/lesser precipitation years,northwest China

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Co-modified Pd/CeO_2-ZrO_2 catalysts for methanol decomposition

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Journal of Energy Chemistry 2014年第6期23卷 755-760页

作者： Ming Zhao Hailong Zhang Xue Li Yaoqiang Chen College of Chemistry Sichuan University sichuan provincial environmental Protection environmental Catalytic Materials Engineering Technology center

Pd/Ce0.8Zro.202 catalysts modified by cobalt were prepared by a sequential impregnation method and characterized by X-ray powder diffraction （XRD）, N2 adsorption/desorption （Brunauer-Emmet-Teller）, oxygen storage capacity （OSC）, CO-chemisorption, H2-temperature-programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The effect of Co on the performance of methanol decomposition was eval- uated at a fixed-bed microreactor. The results showed that the addition of Co can improve the oxygen storage capacity of the catalyst and the dispersion of Pd. XPS results indicated that Pd was in a partly oxidized （Pd6＋, 1〈8〈2） state and Co2＋ was present in Pd catalysts modified by Co. A 90% conversion of methanol was achieved at around 280 ℃ over Pd-Co/Ceo.8Zro.202 catalyst which was 20 ℃ lower than that over Pd/***.202, indicating that both pd6＋and Co2＋ play an important role in improving the catalytic activity of methanol decomposition.

关键词： palladium cobalt methanol decomposition CeO2-Zr02

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Determining hydrothermal deactivation mechanisms on Cu/SAPO-34 NH_(3)-SCR catalysts at low-and high-reaction regions:establishing roles of different reaction sites

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Rare Metals 2022年第6期41卷 1899-1910页

作者： Qing-Jin Lin Ming-Ming Pei Pan Yao Shi Xu Shu-Hao Xu Shuang Liu Hai-Di Xu Yi Dan Yao-Qiang Chen State Key Laboratory of Polymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu 610064China Key Laboratory of Green Chemistry and Technology College of ChemistrySichuan UniversityMinistry of EducationChengdu 610064China .Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu 610064China Weichai Power Co. LtdWeifang 261061China sichuan provincial Automobile Exhaust Purification Engineering Technology Research center Chengdu 610064China sichuan provincial environmental Protection environmental Catalytic Materials Engineering Technology center Chengdu 610064China

Hydrothermal deactivation is a constant chal-lenge in commercial catalytic process aimed at NOx emission control,which may be observed in the low(150-400℃)or high(400-550℃)-reaction *** the best of our knowledge,there is a lack of systematic research regarding the correlation between the reaction sites and the mechanism of hydrothermal degradation at various reaction *** a targeted investigation of this,Cu/zeolite catalysts have been prepared using different amounts of polyvinyl alcohol for adjusting their redox and acid *** catalysts exhibit hydrothermal deactivation in different reaction *** change is observed in the reaction mechanism even with hydrother-mal deactivation,but various reaction sites determine the performance deterioration in the low-and high-reaction *** redox properties and weak acid sites affect the hydrothermal deactivation in the low-reaction region,whereas the moderate/strong acid sites related to the structure mainly influence the hydrothermal deactivation in the high-reaction *** work provides several the-oretical insights for optimizing the hydrothermal stabilities of Cu/zeolite catalysts.

关键词： Deterioration mechanism Bifunctional sites Temperature regions Selective catalytic reduction Cu/zeolite

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Real-time,single-particle chemical composition,volatility and mixing state measurements of urban aerosol particles in southwest China

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Journal of environmental Sciences 2024年第2期136卷 361-371页

作者： Luyao Chen Junke Zhang Jiaqi Li Xiaojuan Huang Yuzheng Xiang Jing Chen Tingru Pan Wei Zhang Faculty of Geosciences and environmental Engineering Southwest Jiaotong UniversityChengdu 611756China School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China sichuan environmental Monitoring center Chengdu 610074China

To investigate the volatility of atmospheric particulates and the evolution of other particulate properties(chemical composition,particle size distribution and mixing state)with temperature,a thermodenuder coupled with a single particle aerosol mass spectrometer was used to conduct continuous observations of atmospheric fine particles in Chengdu,southwest *** of their complex sources and secondary reaction processes,the average mass spectra of single particles contained a variety of chemical components(including organic,inorganic and metal species).When the temperature rose from room temperature to280℃,the relative areas of volatile and semi-volatile components decreased,while the relative areas of less or non-volatile components ***(>80%)nitrate and sulfate existed in the form of NH_(4)NO_(3)and(NH_(4))_(2)SO_(4),and their volatilization temperatures were50–100℃and 150–280℃,*** contribution of biomass burning(BB)and vehicle emission(VE)particles increased significantly at 280℃,which emphasized the important role of regional biomass burning and local motor vehicle emissions to the core of *** the increase in temperature,the particle size of the particles coated with volatile or semi-volatile components was reduced,and their mixing with secondary inorganic components was significantly *** formation of K-nitrate(KNO_(3))and K-sulfate(KSO_(4))particles was dominated by liquid-phase processes and photochemical reactions,*** KNO_(3)and BB particles is the key to improving *** new results are helpful towards better understanding the initial sources,pollution formation mechanisms and climatic effects of fine particulate matter in this megacity in southwest China.

关键词： Atmospheric fine particles TD-SPAMS Chemical composition Volatility Mixing state

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Characteristics,evolution,and regional differences of biomass burning particles in the sichuan Basin,China

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Journal of environmental Sciences 2020年第3期32卷 35-46页

作者： Jinqi Luo Junke Zhang Xiaojuan Huang Qin Liu Bin Luo Wei Zhang Zhihan Rao Yangchun Yu Faculty of Geosciences and environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Plateau Atmosphere and Environment Key Laboratory of sichuan Province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225China sichuan environmental Monitoring center Chengdu 610074China Shandong Academy for environmental Planning Jinan 250101China

The sichuan Basin has experienced serious air pollution from fine particulate matter(PM2.5) in the past few years with biomass burning has been identified as a major source of PM2.5 in this *** used single particle aerosol mass spectrometer to investigate the characteristics of biomass burning particles in three interacting cities representing different types of urban environment in the sichuan Basin.A total of 739,794,279,610,and380,636 biomass burning particles were detected at Ya’an,Guang’an,and Chengdu,which represented 42%,69%,and 61%,respectively,of the total number of *** analyzed the chemical composition,transportation,and evolution of biomass burning *** contribution of K-elemental carbon and K-secondary inorganic particles was highest in Ya’an(36%) and Guang’an(47%),respectively,reflecting the important role of fresh biomass burning particles and long-distance transport in these two *** masses originating from different directions corresponded to different levels of PM2.5 and the contributions of polluted clusters increased significantly on polluted *** and secondary inorganic biomass burning particles increased pollution at Ya’an and Guang’an,respectively,but dominated different stages of pollution in Chengdu.K-nitrate particles were formed by photochemical reactions,whereas K-sulfate particles were formed by both photochemical and liquid-phase *** of the degree of particle aging showed that there were more fresh particles at Ya’an and more aged particles at Guang’*** results are useful in helping our understanding of the characteristics of biomass burning particles and evaluating their role in PM2.5 pollution in the sichuan Basin.

关键词： Single particles Biomass burning particles Evolution Regional differences sichuan basin

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Temporal-spatial patterns of intestinal parasites of the Hooded Crane(Grus monacha) wintering in lakes of the middle and lower Yangtze River floodplain

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Chinese Birds 2014年第1期5卷 40-48页

作者： Wei Huang Lizhi Zhou Niannian Zhao Institute of Biodiversity and Wetland Ecology School of Resources and Environmental Engineering Anhui University Anhui provincial Species information center Anhui Shengjin Lake National Nature Reserve

Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wetlands,which are prone to parasite infection, thus monitoring the diversity of parasites is important for sound wetland management and protection of this ***: From November 2012 to April 2013, we collected 821 fresh faecal samples from the three lakes(Poyang,Caizi and Shengjin Lake) in the lower and middle Yangtze River floodplain, and detected with saturated brine floating and centrifugal sedimentation methods. Parasite eggs were quantified with a modified Mc Master's counting ***: In this study, 11 species of parasites were discovered, i.e., two coccidium(Eimeria gruis, E. reichenowi), five nematodes(Capillaria sp., Strongyloides sp., Ascaridia sp., Trichostrongylus sp., Ancylostomatidae), three trematodes(Echinostoma sp., Echinochasmus sp., Fasciolopsis sp.) and one cestode(Hymenolepis sp.). About 57.7% of the faecal samples showed parasitic infection. All species of parasites were found at the three sites except Hymenolepis which was not found at Poyang Lake. While most samples were affected by only one or two species of parasites, infection by Eimeria spp. was the most common(53.1%). From One-Way ANOVA analysis of the three lakes, parasite species richness index(p = 0.656), diversity index(p = 0.598) and evenness index(p = 0.612) showed no significant difference. According to the statistical analysis of our data, there were no significant difference in parasite species richness index(p = 0.678) and evenness index(p = 0.238) between wintering periods, but a strong difference in diversity index(p < 0.05).Conclusions: Our study suggests that in the wintering Hooded Crane populations, parasite diversity is more sensitive to changes in the overwintering periods than to locations. This also indicates that with the limitations of mig

关键词： Hooded Crane Wintering population Migratory waterbirds Faecal parasite Parasite diversity

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