检索结果-南通市图书馆

Adsorption of chlorophenols from aqueous solutions by pristine and surface functionalized single-walled carbon nanotubes

引用

Journal of environmental Sciences 2016年第5期28卷 187-198页

作者： Han Ding Xin Li Jun Wang Xiaojian Zhang Chao Chen state key joint laboratory of environmental simulation and pollution control School of Environment Tsinghua University

The adsorption of six kinds of chlorophenols on pristine, hydroxylated and carboxylated single-walled carbon nanotubes（SWCNTs） has been investigated. Pseudo-first order and pseudo-second order models were used to describe the kinetic data. All adsorption isotherms were well fitted with Langmuir, Freundlich and Polanyi–Manes models, due to surface adsorption dominating the adsorption process. The close linear relationship between log Kowand log Kdsuggested that hydrophobicity played an important role in the adsorption. The SWCNTs＇ adsorption capacity for chlorophenols was weakened by addition of oxygen-containing functional groups on the surface, due to the loss of specific surface area, the increase of hydrophilicity and the reduction of π–π interaction. The best adsorption capacity of pristine SWCNTs, SWCNT-OH and SWCNT-COOH for six chlorophenols varied from 19 to 84 mg/g, from 19 to 65 mg/g and from 17 to 65 mg/g,respectively. The effect of pH on the adsorption of 2,6-dichlorophenol（2,6-DCP）, was also studied. When p H is over the pK aof 2,6-dichlorophenol（2,6-DCP）, its removal dropped sharply. When ionic strength increased（Na Cl or KCl concentration from 0 to 0.02 mmol/L）,the adsorption capacity of 2,6-DCP on pristine SWCNTs decreased slightly. The comparison of chlorophenols adsorption by SWCNTs, MWCNTs and PAC was made, indicating that the adsorption rate of CNTs was much faster than that of PAC. The results provide useful information about the feasibility of SWCNTs as an adsorbent to remove chlorophenols from aqueous solutions.

关键词： Adsorption Chlorophenols Single-walled carbon nanotubes Isotherms Kinetics Cation–π interaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mesoporous silicas synthesis and application for lignin peroxidase immobilization by covalent binding method

引用

Journal of environmental Sciences 2013年第1期25卷 181-187页

作者： Zunfang Hu Longqian Xu Xianghua Wen environmental simulation and pollution control state key joint laboratory School of EnvironmentTsinghua University

Immobilization of enzymes on mesoporous silicas （MS） allows for good reusability. MS with two-dimensional hexagonal pores in diameter up to 14.13 nm were synthesized using Pluronic P123 as template and 1,3,5-triisopropylbenzene as a swelling agent in acetate buffer. The surface of MS was modified by the silanization reagents 3-aminopropyltriethoxysilane. Lignin peroxidase （LIP） was successfully immobilized on the modified MS through covalent binding method by four agents： glutaraldehyde, 1,4- phenylene diisothiocyanate, cyanotic chloride and water-soluble carbodiimide. Results showed that cyanotic chloride provided the best performance for LiP immobilization. The loaded protein concentration was 12.15 mg/g and the immobilized LiP activity was 812.9 U/L. Immobilized LiP had better pH stability. Acid Orange II was used to examine the reusability of immobilized LiP, showing more than 50% of the dye was decolorized at the fifth cycle.

关键词： mesoporous silica lignin peroxidase covalent binding stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microbial aerosol chemistry characteristics in highly polluted air

引用

Science China Chemistry 2019年第8期62卷 1051-1063页

作者： Ting Zhang Xinyue Li Minfei Wang Haoxuan Chen Maosheng Yao state key joint laboratory of environmental simulation and pollution control College of Environmental Sciences and EngineeringPeking University

Aerosol chemistry is often studied without considering microbial involvements. Here, we investigated time-and size-resolved bacterial aerosol dynamics in air. Under high particulate matter(PM) polluted episodes, bacterial aerosols exhibited a viability of up to 50%–70% in the 0.56–1 μm size range, at which elevated levels of SO42-, NO3- and NH4+ were concurrently *** or acclimated for both industrial use, bacteria such as Psychrobacter spp., Massilia spp., Acinetobacter lwoffii,Exiguobacteriumaurantiacum and Bacillusmegaterium were shown to have experienced massive abundance shifts in polluted air on early mornings and late afternoons, on which rapid new particle formation events were widely reported. Here, Psychrobacter spp. were shown to account for >96% abundance at a corresponding PM2.5 level of 208 μg/m3. These observed bacterial aerosol changes corresponded to the PM2.5 mass peak shift from 3.2–5.6 μm to the high viability size range of 0.56–1 μm. Additionally,elevated levels of soluble Na, Ca, Mg, K, Al, Fe and P elements, required for bacterial growth, were observed to co-occur with those significant bacterial aerosol structure shifts in the air. For particular time-resolved PM2.5 pollution episodes, Acinetobacter,Psychrobacter and Massilia were shown to alternate in dominating the time-resolved aerosol community structures. The results from a HYSPLIT trajectory model simulation suggested that air mass transport played a minor role in affecting the observed bacterial aerosol structure dynamics. All the data here suggested that airborne bacteria in the size range of 0.56–1 μm could be extensively involved in aerosol chemistry in highly polluted humid air.

关键词： bacterial aerosol dynamics in air particulate matter size-and time-resolved bacterial aerosol aerosol chemistry

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characteristics of volatile organic compounds,NO_2,and effects on ozone formation at a site with high ozone level in Chengdu

引用

Journal of environmental Sciences 2019年第1期31卷 334-345页

作者： Yuanyuan Deng Jing Li Yaqi Li Rongrong Wu Shaodong Xie College of environmental Sciences and Engineering State Key Joint Laboratory of Environmental Simulation and Pollution ControlPeking University

Chengdu is a megacity in the southwest of China with high ozone(O_3) mixing *** of volatile organic compounds(VOCs), NO_2 and O_3 with high temporal resolution was conducted in Chengdu to investigate the chemical processes and causes of high O_3 levels. The hourly mixing ratios of VOCs, NO2, and O_3 were monitored by an online system from 28 August to 7 October, 2016. According to meteorological conditions,Chengdu, with relative warm weather and low wind speed, is favorable to O_3 *** of the O_3 in Chengdu may be transported from the downtown area. In O_3 episodes,the average mixing ratios of NO_2 and O_3 were 20.20 ppbv and 47.95 ppbv, respectively. In non-O_3 episodes, the average mixing ratios of NO_2 and O_3 were 16.38 ppbv and 35.15 ppbv,respectively. The average mixing ratio of total VOCs(TVOCs) was 40.29 ppbv in non-O_3 episodes, which was lower than that in O_3 episodes(53.19 ppbv). Alkenes comprised51.7% of the total O_3 formation potential(OFP) in Chengdu, followed by aromatics which accounted for 24.2%. Ethylene, trans-pentene, propene, and BTEX(benzene, ethylbenzene,toluene, m/p-xylene, o-xylene) were also major contributors to the OFP in Chengdu. In O_3 episodes, intensive secondary formations were observed during the campaign. Oxygenated VOCs(OVOCs), such as acetone, Methylethylketone(MEK), and Methylvinylketone(MVK)were abundant. Isoprene rapidly converted to MVK and Methacrolein(MACR) during O_3 episodes. Acetone was mainly the oxidant of C3-C5 hydrocarbons.

关键词： Ozone formation VOCs NO2 OFP Diurnal variation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fabrication of TiO_2 Nanotube Arrays by Rectified Alternating Current Anodization

引用

Journal of Materials Science & Technology 2015年第1期31卷 23-29页

作者： Han Song Jing Shang Chen Suo state key joint laboratory of environmental simulation and pollution control College of Environmental Sciences and EngineeringPeking University

Anodization is a popular method of preparing TiO2nanotube array films（TiNTs） by using direct current（DC）power as the driving *** this study,three driving voltage modes,namely,the sine alternating current（sine） mode,the full-wave rectification of sine waves via four diodes（sine-4D,where D means diode） mode,and the DC mode,were used to prepare TiNTs by *** 20 V,TiNTs were formed under sine-4D mode but only irregular porous TiO2films were formed under DC *** 50 V,TiNTs formed under both the sine-4D and DC *** TiNTs formed in the sine mode anodization at either 20 or 50 *** with the DC mode,the sine-4D mode required a lower oxidation voltage for TiNT formation,which suggests that sine-4D is an economical,convenient,and efficient driving voltage for TiNT preparation by *** morphologies and structures of TiNT samples anodized at 50 V in the sine-4D and DC modes at different oxidation time（1,5,10,30,60,and 120 min） were *** growth processes were similar between the studied ***,the growth rate of the films was faster under the sine-4D mode than the DC mode during the first 30 min of anodization.

关键词： TiO2nanotube Anodization Alternating current Growt

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products

引用

Journal of environmental Sciences 2016年第6期28卷 158-170页

作者： Jing Li Yu Bo Shaodong Xie College of environmental Sciences and Engineering State Key Joint Laboratory of Environmental Simulation and Pollution ControlPeking University

With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°× 0.25° and a temporal resolution of1 month was established based on the moderate resolution imaging spectroradiometer（MODIS） Thermal Anomalies/Fire Daily Level3 Global Product（MOD/MYD14A1）. Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO2, CO, CH4,nonmethane volatile organic compounds（NMVOCs）, N2O, NOx, NH3, SO2, fine particles（PM2.5）,organic carbon（OC）, and black carbon（BC） were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43,1.09, 0.34, and 0.06 Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June（37%）.Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N2O to a high of within ± 169% for NH3.

关键词： Crop residue open burning Air quality Emission inventory Moderate resolution imaging spectroradiometer(MODIS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Peroxyacetyl nitrate observed in Beijing in August from 2005 to 2009

引用

Journal of environmental Sciences 2014年第10期26卷 2007-2017页

作者： Tianyu Gao Li Han Bin Wang Guang Yang Zhenqiang Xu Limin Zeng Jianbo Zhang state key joint laboratory of environmental simulation and pollution control College of Environmental Sciences and EngineeringPeking University

Measurements of peroxyacetyl nitrate（PAN） were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3（2005） to 11.7 μg/m3（2007）; however, it decreased rapidly in 2008（4.1 μg/m3）.Generally, the variation over the 5 years showed a rise in the first part of the study period,followed by a decline. We considered two categories of local and regional air masses in this study, which revealed that the PAN concentration in Beijing was affected mainly by southeastern air masses. The August PAN variation was influenced predominantly by local air masses in 2005,but by 2009 regional air masses had become more important. This study showed the level and variation of PAN in the month of August in 5 consecutive years for the first time, and proved that control measures are useful in decreasing photochemical pollution; hence, these measures are probably feasible for other megacities too. Furthermore, this method of analyzing regional and local impacts might be useful for other studies as well.

关键词： PAN Beijing Transport Local Regional

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

simulation of organic nitrates in Pearl River Delta in 2006 and the chemical impact on ozone production

引用

Science China Earth Sciences 2018年第2期61卷 228-238页

作者： CHEN XiaoRui WANG HaiChao LU KeDing state key joint laboratory of environmental simulation and pollution control College of Environmental Sciences and Engineering Peking University

Organic nitrates are secondary atmospheric pollutants that play a key role in ozone and aerosol production. This study focused on the simulation of organic nitrates through a box model coupled with RACM2 （Regional Atmospheric Chemistry Mechanism, version 2）, based on data from the PRIDE-PRD2006 campaign in Backgarden, China. Our study found that an overestimation of organic nitrate production rate was generated by the model. Furthermore, the effective production ratio （a^ff） of organic nitrates was around 0.033 after optimizing its chemical production module. The chemical impacts of organic nitrates on ozone production were related to VOC-OH reactivity and aeff. We found that VOC-OH reactivity was positively related to aeff, resulting in the suppression of ozone production caused by organic nitrates, which showed that P（Ox=O3＋NO2） increased initially and subsequently decreased with VOC-OH reactivity. These results highlight the importance of organic nitrate＇s impact on ozone production in strategies to control ozone pollution, specifically regarding the reduction of low-molecular-weight VOCs in the Pearl River Delta.

关键词： Organic nitrates Ozone RACM2 Pearl River Delta

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

引用

Journal of environmental Sciences 2015年第2期27卷 128-136页

作者： Ming Wang Wentai Chen Min Shao Sihua Lu Limin Zeng Min Hu state joint key laboratory of environmental simulation and pollution control College of Environmental Sciences and EngineeringPeking University

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons,and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25 th to 27 th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th–8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene（T/B） during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was5.8 ppb/ppb, significantly higher than the values of 0.2–1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.

关键词： Carbonyl compounds Source apportionment Industrial emission Yangtze River Delta

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evaluating the emission status of light-duty gasoline vehicles and motorcycles in Macao with real-world remote sensing measurement

引用

Journal of environmental Sciences 2014年第11期26卷 2240-2248页

作者： Yu Zhou Ye Wu Shaojun Zhang Lixin Fu Jiming Hao School of Environment State Key Joint Laboratory of Environment Simulation and Pollution Control Tsinghua University state environmental Protection key laboratory of Sources and control of Air pollution Complex

Roadside remote sensing measurement was used to explore the real-world emission status of light duty gasoline vehicles （LDGVs） and motorcycles in Macao. Both fuel-based and distance-based emission factors were derived using the mass balance method. The emission concentration profile of LDGVs illustrated the benefits of tightening emission standards at the source country or region of import. The distance-based emission factors for CO, HC and NOx of LDGVs registered before 2000 were 8.00, 1.04 and 1.36 g/km, respectively. The distance-based emission factors for CO, HC and NOx of LDGVs registered in or after 2000 were 1.16, 0.15 and 0.18 g/km, respectively. The fuel-based CO emission factors of light duty motorcycles （LDMCs） and heavy duty motorcycles （HDMCs） registered before 2000 were about 10 times higher than those of LDGVs of the same age group. As the emissions of LDGVs decreased more quickly after 2000, the gap widens for newer vehicles. The distance-based HC emission factors of LDMCs and HDMCs registered before 2000 were 4.81 and 2.91 g/km, respectively. The distance-based HC emission factors of LDMCs and HDMCs registered in or after 2000 were 3.52 and 0.93 g/km, respectively. The poor emission performance of motorcycles and their larger share in the traffic flow will cause them to be the major contributor to traffic CO and HC emissions. LDMCs, especially two-stroke models, should be the priority for vehicle emission control efforts in Macao.

关键词： Emission Remote sensing Macao Motorcycle

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：