Long-term observations of tropospheric NO2, SO2 and HCHO by MAX-DOAS in Yangtze River Delta area, China

Yangtze River Delta(YRD) area is one of the important economic zones in China. However,this area faces increasing environmental problems. In this study, we use ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS) network in Eastern China to retrieve variations of NO_2, SO_2, and formaldehyde(HCHO) in the YRD area. Three cities of YRD(Hefei, Nanjing, and Shanghai) were selected for long-term observations. This paper presents technical performance and characteristics of instruments, their distribution in YRD, and results of vertical column densities(VCDs) and profiles of NO_2, SO_2, and HCHO.Average diurnal variations of tropospheric NO_2 and SO_2 in different seasons over the three stations yielded minimum values at noon or in the early afternoon, whereas tropospheric HCHO reached the maximum during midday hours. Slight reduction of the pollutants in weekends occurred in all the three sites. In general trace gas concentrations gradually reduced from Shanghai to Hefei. Tropospheric VCDs of NO_2, SO_2, and HCHO were compared with those from Ozone Monitoring Instrument(OMI) satellite observations, resulting in R~2 of 0.606, 0.5432, and 0.5566, respectively. According to analysis of regional transports of pollutants, pollution process happened in YRD under the north wind with the pollution dissipating in the southeast wind. The feature is significant in exploring transport of tropospheric trace gas pollution in YRD, and provides basis for satellite and model validation.     

分段进水生物接触氧化工艺处理河道污水的试验研究

选择滇池入湖污染负荷最高的大清河为对象,以分段进水生物接触氧化(SFBC)工艺对河道污水开展了分流处理的试验研究,已完成冬季枯水期、春季枯水期及夏季丰水期3个时期的研究.结果表明.SFBC工艺对水质变化具有很好的适应性,调整各时期的运行参数,可以使COD及TP的去除率分别稳定在50%和40%左右,但TN的去除受水温及溶解氧等的影响很大,在逐渐稳定后去除率可达到20%左右.接种活性污泥可以加快装置的启动.但总体去除效果不及来水自然驯化的污泥.随着运行时间延长以及来水带入河道底泥的影响.有无接种污泥在处理效率上的差别逐渐消失.     

Pd/CeZr/TiO2/Al2O3蜂窝状金属丝网催化剂选择催化还原NOX

采用溶胶-凝胶法和浸渍法制备了Pd/CeZr/TiO2Al2O3蜂窝状金属丝网催化剂,并将其应用于在富氧条件下以丙烯选择催化还原NOx的研究.利用扫描电镜(SEM)分析了钛酸四丁酯的含量以及涂敷次数对TiO2涂层的影响,系统地考察了Pd含量、氧气浓度和空速对蜂窝状金属丝网催化剂催化性能的影响.实验结果表明,采用钛酸四丁酯的含量为20.0%的溶胶,涂敷2次,可以在金属丝网载体上氧化铝涂层表面获得均匀、无皲裂的TiO2涂层;Pd含量在0.23%～1.06%的范围内, NOx的转化率随Pd含量的增加而减小, Pd含量为0.23%时, NOx表现最高的NOx转化率;反应气体中氧气浓度从1.5%增加到6.0%, NOx的转化率随氧气浓度的增加而增大,当氧气浓度高于6.0%, NOx的转化率则随氧气浓度的增加而迅速减小; NOx的转化率随着空速的增加而降低,在高温条件下空速对转化率的影响要大于在低温条件下.     

环糊精在土壤有机污染物治理中的应用

综述了环糊精及其衍生物在土壤弱极性有机物治理中的应用和原理。环糊精可与土壤中弱极性有机污染物形成主客包合物,从而增加其水溶性促进其从土壤中解吸去除;能够同时去除金属离子;能够改变有机污染物理化性质促进其光解;可降低有机污染物毒性促进其微生物降解。     

Determination of polyfluoroalkyl compounds in water and suspended particulate matter in the river Elbe and North Sea, Germany

The distribution of polyfluoroalkyl compounds (PFCs) in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied. The PFCs quantified included C₄-C₈ perfluorinated sulfonates (PFSAs), 6:2 fluorotelomer sulfonate (6:2 FTS), C₆ and C₈ perfluorinated sulfinates (PFSiAs), C₄-C₁₂ perfluorinated carboxylic acids (PFCAs), perfluoro-3,7-dimethyl-octanoic acid (3,7m₂-PFOA), perfluorooctane sulfonamide (FOSA), and n-ethyl perfluroctane sulfonamidoethanol (EtFOSE). PFCs were mostly distributed in the dissolved phase, where perfluorooctanoic acid (PFOA) dominated with 2.9–12.5 ng/L. In the suspended particulate matter FOSA and perfluorooctane sulfonate (PFOS) showed the highest concentrations (4.0 ng/L and 2.3 ng/L, respectively). The total flux of ΣPFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate phase. This indicates that the river Elbe acts as a source of PFCs into the North Sea. However, the concentrations of perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) in the North Sea were higher than that in the river Elbe, thus an alternative source must exist for these compounds.     

静电空气灭菌净化机研究及其应用

通过分析负离子型、过滤型、静电型和静电与过滤复合型这四种常见类型的空气净化机存在的问题,并通过对横向电极极配的除尘效果的研究,提出采用横向电极极配的静电空气净化机,并在应用中增加了荷电电极,测试结果显示该机型可以净化空气中的一氧化碳、二氧化碳、烟雾、细菌和释放适量负离子,特别是对空气中的细菌具有高达90%的灭菌能力,该机型是全静电型,使用中无需更换任何过滤元件,可成为高效、节能、实用的新型静电空气净化机。     

平衡——生态健康之刁——平衡与生态健康之关系

“平衡”是世间万物之本,而生态健康却与自然、社会、政治以及人体平衡等有着千丝万缕的联系。随着人类社会经济的不断发展和人们生活水平的不断提高,生态健康已成为现代化生活的一个重要标志,它直接关系到人们的健康生活。本文提出了“平衡”是生态健康之本,从一个新颖的视角一“平衡”,简明地论述了平衡在人类的生存发展过程中的重要性,以及它与生态健康之间的密切关系。文章中阐述的观点值得思考,对如何理解和审视“生态健康”有着重要的启示作用。     

Organic matter extracted from activated sludge with ammonium hydroxide and its characterization

In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter (accounting for 32.2% and 48.0% of the bulk organic matter,respectively),whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low (accounting for 9.2%,5.8% and 4.8%,respectively).Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH 3 ·H 2 O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics.     

Germination of Deyeuxia angustifolia as affected by soil type, burial depth, water depth and oxygen level

Deyeuxia angustifolia is a dominant species in the Sanjiang Plain, the largest freshwater marsh wetland in China. However, this species has declined because of great environment changes. In the effects of sea-level rise and greenhouse gas, magnitude and frequency of flood and rate of deposit in wetland increased greatly. Thus, in this paper, effects of soil environment (soil type, burial depth, water depth and oxygen concentration) on seed germination of D. angustifolia were investigated. Both soil type and burial depth affected seedling emergence. Seedlings emerged through 1-, 2-, 4-mm sand, and at 1-and 2-mm mud. Regardless of soil, seedling emergence time increased and emergence percentage decreased with increasing burial depth. For example, seedlings started to emerge on the 4th day and the final emergence percentage was 30% when covered with1-mm mud, whereas the initial emergence time was on the 6th day and the final emergence percentage was only 8% when covered with 2-mm mud. At the same burial depth, emergence percentage was higher in sand than in mud. Increasing water depth inhibited seed germination. Germination percentage in 2-cm water level (20%) was 1.2 times higher than that in 12-cm water level (9%). Oxygen concentration also affected germination. In the 21% oxygen concentration, germination was started on the 2nd day and the germination percentage was 36%, while seed started to germinate on the 4th day and the germination percentage was only 3% at the 7% oxygen concentration. These data indicate that seed germination of D. angustifolia was highly sensitive to soil type, burial depth, water depth, oxygen concentration, and these responses may be an explicit indication of maladjustment to environment changes, and an important reason accounting for the decline of this species in the Sanjiang Plain.     

Two-step fast microwave-assisted pyrolysis of biomass for bio-oil production using microwave absorbent and HZSM-5 catalyst

A novel technology of two-step fast microwave-assisted pyrolysis(f MAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent(Si C) and HZSM-5catalyst. Effects of f MAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The f MAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1:100 to 1:20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step f MAP process, two-step f MAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio.