Removal of formaldehyde over MnxCe1-xO2 catalysts: Thermal catalytic oxidation versus ozone catalytic oxidation

MnxCe1- xO2（x： 0.3–0.9） prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde（HCHO）. At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of Ce O2 to form a solid solution. The catalytic activity was best at x = 0.5, at which the temperature of 100% removal rate is the lowest（270°C）. The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5 wt.% Cu Oxinto Mn0.5Ce0.5O2. With ozone catalytic oxidation, HCHO（61 ppm） in gas stream was completely oxidized by adding 506 ppm O3 over Mn0.5Ce0.5O2 catalyst with a GHSV（gas hourly space velocity） of 10,000 hr-1at 25°C. The effect of the molar ratio of O3 to HCHO was also investigated. As O3/HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O3/HCHO ratio of 8, the mineralization efficiency of HCHO to CO2 was 86.1%. At 25°C, the p-type oxide semiconductor（Mn0.5Ce0.5O2） exhibited an excellent ozone decomposition efficiency of 99.2%,which significantly exceeded that of n-type oxide semiconductors such as Ti O2, which had a low ozone decomposition efficiency（9.81%）. At a GHSV of 10,000 hr-1, [O3]/[HCHO] = 3 and temperature of 25°C, a high HCHO removal efficiency（≥ 81.2%） was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal.     

Salinity influence on soil microbial respiration rate of wetland in the Yangtze River estuary through changing microbial community

Estuarine wetland, where freshwater mixes with salt water, comprises different regions（rivers and marine ecosystems） with significantly varying tidal salinities. Two sampling areas, ZXS and JS, were selected to investigate the effect of tidal salinity on soil respiration（SR）. ZXS and JS were located in Zhongxia Shoal and Jiangyanan Shoal of Jiuduansha Wetland respectively, with similar elevation and plant species, but significantly different in salinity. The results showed that with almost identical plant biomass, the SR and soil microbial respiration（SMR） of the tidal wetland with lower salinity（JS） were significantly higher than those of the tidal wetland with higher salinity（ZXS）（p 〈 0.05）. However, unlike SMR and SR, the difference in the soil microbial biomass（SMB） was not significant（p 〉 0.05）with the SMB of ZXS a little higher than that of JS. The higher SMR and SR of JS may be closely connected to the soil microbial community structures and amount of dominant bacteria. Abundant β- and γ-Proteobacteria and Actinobacteria in JS soil, which have strong heterotrophic metabolic capabilities, could be the main reason for higher SMR and SR,whereas a high number of ε-Proteobacteria in ZXS, some of which have carbon fixation ability, could be responsible for relatively lower carbon output. Path analysis indicated that soil salinity had the maximum negative total influencing coefficient with SMR among the various soil physical and chemical factors, suggesting that higher soil salinity, restricting highly heterotrophic bacteria, is the principle reason for lower SMR and SR in the ZXS.     

中国木质林产品碳足迹的产业链分布特征分析

中国是木质林产品的生产、消费和出口大国,分析其产品碳足迹的分布特征对于林产行业的国际贸易和节能减排工作具有重要意义。文章采用投入产出生命周期模型计算中国木质林产品的碳足迹,并对不同种类木质林产品产业链上的碳足迹分布进行分析。研究结果表明,产品碳足迹总量最大的木质林产品是木家具(占总量的36%),而单位产品碳足迹强度最大的木质林产品是纸制品(占整体的16%);针对林产品行业内部的产业链角度,碳足迹的主要流量发生在从用材林的种植和养护业到最终产品的制造;林产品产业行业外部,碳足迹的贡献则主要来自于金属冶炼及压延加工业、化石燃料开采业等行业,这2个行业碳足迹贡献分别占21%和18%;整体上,中国木质林产品生产中温室气体的排放以燃料燃烧产生的二氧化碳为主,这与产业链外其他行业的碳贡献密不可分。研究表明,通过碳足迹在产业链上的分布可以有助于分析林产品碳排放的工作重心。     

四种环境雌激素对斑马鱼内脏团抗氧化防御系统的影响研究——17B-雌二醇与三种增塑剂DMP、DBP、DOP的影响

以斑马鱼(Danio rerio)为受试动物,研究了四种环境雌激素-17β-雌二醇(E2)和三种增塑剂(DMP、DBP、DOP)对其内脏团的氧化损伤及应激效应。经急性毒性实验,得到E2、DMP、DBP、DOP对成体斑马鱼96 h的半数致死浓度(LC50)分别为2.51、12.33、9.67、9.89 mg·L-1。在此基础上分别设置5个浓度梯度,研究E2(暴露2 d,4 d)、DMP、DBP、DOP(暴露4 d)对斑马鱼内脏团的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽硫转移酶(GST)活性以及丙二醛(MDA)含量的影响。结果表明,SOD、CAT、GST、MDA对这四种环境激素都非常敏感,其中SOD、CAT、GST活性的影响均呈现先诱导后抑制的趋势,而MDA含量则随着污染物浓度的升高而增加。高浓度暴露条件下,E2(0.4 mg·L-1)和DMP、DBP、DOP(0.8 mg·L-1)对SOD、CAT、GST活性均有显著抑制(p0.05),MDA的含量有显著升高(p0.05)。可见,E2、DMP、DBP、DOP会导致斑马鱼内脏团氧化损伤,并且在同等浓度下E2的毒性明显高于三种增塑剂。     

Effect of ozone on the performance of a hybrid ceramic membrane-biological activated carbon process

Two hybrid processes including ozonation-ceramic membrane-biological activated carbon （BAC） （Process A） and ceramic membrane-BAC （Process B） were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm （UV254, a parameter indicating organic matter with aromatic structure） were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively.     

Removal of SO2 from O2-containing flue gas by activated carbon fiber (ACF) impregnated with NH3

Adsorption of SO(2) from the O(2)-containing flue gas by granular activated carbons (GACs) and activated carbon fibers (ACFs) impregnated with NH(3) was studied in this technical note. Experimental results showed that the ACFs were high-quality adsorbents due to their unique textural properties. In the presence of moisture, the desulphurization efficiency for the ACFs was improved significantly due to the formation of sulfuric acid. After NH(3) impregnation of ACF samples, nitrogen-containing functional groups (pyridyl C(5)H(4)N- and pyrrolyl C(4)H(4)N-) were detected on the sample surface by using an X-ray photoelectron spectrometer. These functional groups accounted for the enhanced SO(2) adsorption via chemisorption and/or catalytic oxidization.     

贸易协定对我国污染排放的影响后评价模型初步研究

当今世界全球化推进到一个新的阶段,全球双边/区域贸易协定的数量呈现不断上升的趋势,而贸易自由化在促进经济扩张的同时,也导致资源的大量消耗和污染排放。因此需要建立有关环境影响评价机制,及时跟踪反馈,有针对性地引导中国出口方向的转变和进口水平的提升,为落实后续的监督管理,以及我国在贸易协定谈判或协定升级谈判中处理贸易与环境问题提供决策建议。在国内外已普遍开展贸易协定环境影响预评价并忽略后评价的背景下,本文选取工业行业大气污染排放作为指标,通过整合现有的贸易协定对经济影响测算的因素剥离方法以及经济对环境影响测算的环境投入产出分析方法,初步构建贸易协定对我国工业污染排放的影响后评价模型。建议下一步:建立贸易协定环境影响评价制度,定期开展评估;积极跟踪并参与国际贸易谈判,适时向商务部门提出打造绿色贸易的建议;加强环境与贸易领域能力建设,提升我国应对环境与贸易问题的能力。     

Quantifying the human health benefits of curbing air pollution in Shanghai

Urban development in the mega-cities of Asia has caused detrimental effects on the human health of its inhabitants through air pollution. However, averting these health damages by investing in clean energy and industrial technologies and measures can be expensive. Many cities do not have the capital to make such investments or may prefer to invest that capital elsewhere. In this article, we examine the city of Shanghai, China, and perform an illustrative cost/benefit analysis of air pollution control. Between 1995 and 2020 we expect that Shanghai will continue to grow rapidly. Increased demands for energy will cause increased use of fossil fuels and increased emissions of air pollutants. In this work, we examine emissions of particles smaller than 10 microm in diameter (PM10), which have been associated with inhalation health effects. We hypothesize the establishment of a new technology strategy for coal-fired power generation after 2010 and a new industrial coal-use policy. The health benefits of pollution reduction are compared with the investment costs for the new strategies. The study shows that the benefit-to-cost ratio is in the range of 1-5 for the power-sector initiative and 2-15 for the industrial-sector initiative. Thus, there appear to be considerable net benefits for these strategies, which could be very large depending on the valuation of health effects in China today and in the future. This study therefore provides economic grounds for supporting investments in air pollution control in developing cities like Shanghai.