Characteristics and source apportionment of VOCs measured in Shanghai,China

Volatile organic compounds (VOCs) were measured from 2007 to 2010 at the center of Shanghai, China. Because VOCs are important precursors for ozone photochemical formation, detailed information of VOC sources needs to be investigated. The results show that the measured VOC concentrations in Shanghai are dominated by alkanes (43%) and aromatics (30%), following by halo-hydrocarbons (14%) and alkenes (6%). Based on the measured VOC concentrations, a receptor model (PMF; positive matrix factorization) coupled with the information related to VOC sources (the distribution of major industrial complex, meteorological conditions, etc.) is applied to identify the major VOC sources in Shanghai. The result shows that seven major VOC sources are identified by the PMF method, including (1) vehicle related source which contributes to 25% of the measured VOC concentrations, (2) solvent based industrial source to 17%, (3) fuel evaporation to 15%, (4) paint solvent usage to 15%, (5) steel related industrial production to 12%, (6) biomass/biofuel burning to 9%, and (7) coal burning to 7%. Furthermore, ozone formation potential related to VOC sources is calculated by the MIR (maximum incremental reactivity) technique. The most significant VOC source for ozone formation potential is solvent based industrial sources (27%), paint solvent usage (24%), vehicle related emissions (17%), steel related industrial productions (14%), fuel evaporations (9%), coal burning (6%), and biomass/biofuel burning (3%). The weekend effect on the VOC concentrations shows that VOC concentrations are generally higher in the weekdays than in the weekends at the sampling site, suggesting that traffic conditions and human activities have important impacts on the VOC emissions in Shanghai.     

光催化与生物技术联用工艺处理油漆废气中试研究

光催化与生物技术联用工艺用于油漆生产、加工过程有机废气的现场处理,中试实验结果表明:油漆生产、加工过程现场的主要污染物是甲苯、乙苯、间/对二甲苯和邻二甲苯等苯系物,浓度在27～55 mg/m3之间。单独使用光催化和微生物技术现场处理这些苯系物,其去除效率都不很高。虽然在中试开始阶段光催化对苯系物的平均去除效率达到了86.2%,在中试稳定期,光催化技术对苯系物的平均去除效率却只有67.6%,而生物滴滤床在成功挂膜之后对现场有机废气的平均去除效率也仅为67.5%。但是将这两种工艺联合使用之后,在中试稳定期该组合工艺对苯系物的平均去除效率可以达到99.2%。     

一次光化学污染过程中O_3和NOx的垂直梯度观测研究

为了研究2008年北京奥运会前期污染物浓度变化特征,对北京气象塔3层高度上的大气污染物(NO2和O3)进行加强观测,分析其变化特征。观测结果表明,由于北京奥运会前期采取了严格的空气质量控制措施,NO2浓度相对车辆限行前下降了45.3%,且随着高度递增逐渐降低;O3浓度最大值和日均值有所降低,其最大值出现时间较10年前提前了1~2 h,且有4 h左右处于相对平稳状态。O3浓度峰值主要是受NO2的控制,O3浓度峰值出现时间提前反映出北京大气氧化效率不断提高。对于观测期间出现光化学污染事件,利用同期气象资料和大气污染监测数据分析,发现造成这次大气污染的主要原因是气象因子:地面多处于弱高压场控制中,大气层结稳定,风力较弱(小于2 m/s),并伴随着连续高温、强辐射和低湿。     

斜发沸石对城市污水处理厂二级出水中氨氮的处理效果研究

通过静态实验,研究天然斜发沸石去除城市污水处理二级出水中氨氮的性能。研究结果表明,投加量越大,沸石对废水中氨氮的去除率越高,但是吸附容量越低;沸石对氨氮的去除具有短时间内快速吸附,然后缓慢平衡的特点;粉末状沸石对氨氮的去除效果明显好于颗粒状沸石;pH对氨氮去除率有显著影响,pH值为6时,沸石对氨氮的去除率最高。NaCl和NaOH溶液对沸石的改性具有明显的效果,HCl溶液对沸石的改性作用不明显。     

鼓泡反应器中液相络合催化同时脱硫脱硝的研究

在鼓泡反应器中考察了[Co(en)3]2+同时吸收去除SO2和NO的影响因素,实验结果表明,pH值和脱硫剂种类是影响乙二胺合钴同时脱除NO和SO2的最重要影响因素,烟气中的氧促进乙二胺合钴吸收NO和SO2,烟气中的SO2,CO2和NO2对乙二胺合钴吸收NO具有抑制作用。在实验条件温度为20℃,pH为13.0,[Co(en)3]2+浓度为0.025 mol/L,加入1 g NH3.H2O的脱硝率更好,连续吸收60 min,脱硝率均保持在93.5%,加入NaOH和NH3.H2O的脱硫效果最好。乙二胺合钴络合同时脱除NO和SO2完全可以在一个装置中完成。     

Effect of fluorescent silica nanoparticles in embryo and larva of Oryzias latipes: sonic effect in nanoparticle dispersion

We characterized fluorescent silica nanoparticles (FNPs), which had been applied in many biological systems, in fish embryo rearing media (ERM) solution and evaluated the potential toxicity to the early development of Oryzias latipes embryos. Distribution of FNPs in embryos and larvae of O. latipes was studied by fluorescent and confocal laser scanning microscopic studies. Embryos exposed to three different concentrations of FNPs in stirred or sonicated ERM solutions were observed up to 2 d after hatching. FNPs had a negligible effect on the hatchability of O. latipes embryos; however, compared to controls, more than 30% of eggs were abnormal in 10 and 50 mg FNP L⁻¹ solutions. We found that the toxic effect was increased in sonicated FNP solution, which seems to be related with the dissolution of FNPs in ERM solutions that could be accelerated by sonication. Further study found that the CaCl₂ included in ERM solution might enhance the dissolution of the FNPs and the silicate ion released from FNPs partially contributed to larval toxicity. This study showed that some nanoparticles may not be stable in biological fluids even if they are stable in water. Dissolution factors such as sonication and cellular components should be considered in biological application of nanoparticles.     

Size-differentiated chemical characteristics of Asian paleo dust: records from aeolian deposition on Chinese Loess Plateau

The Chinese Loess Plateau (CLP) receives and potentially contributes to Asian dust storms that affect particulate matter (PM) concentrations, visibility, and climate. Loess on the CLP has experienced little weathering effect and is regarded as an ideal record to represent geochemical characteristics of Asian paleo dust. Samples were taken from 2-, 9-, and 15-m depths (representing deposition periods from approximately 12,000 to approximately 200,000 yr ago) in the Xi Feng loess profile on the CLP. The samples were resuspended and then sampled through total suspended particulates (TSP), PM10, PM2.5, and PM1 (PM with aerodynamic diameters < approximately 30, 10, 2.5, and 1 microm, respectively) inlets onto filters for mass, elemental, ionic, and carbon analyses using a Desert Research Institute resuspension chamber. The elements Si, Ca, Al, Fe, K, Mg, water-soluble Ca (Ca2+), organic carbon, and carbonate carbon are the major constituents (> 1%) in loess among the four PM fractions (i.e., TSP, PM10, PM2.5, and PM1). Much of Ca is water soluble and corresponds with measures of carbonate, indicating that most of the calcium is in the form of calcium carbonate rather than other calcium minerals. Most of the K is insoluble, indicating that loess can be separated from biomass burning contributions when K+ is measured. The loess has elemental abundances similar to those of the upper continental crust (UCC) for Mg, Fe, Ti, Mn, V, Cr, and Ni, but substantially different ratios for other elements such as Ca, Co, Cu, As, and Pb. These suggest that the use of UCC as a reference to represent pure or paleo Asian dust needs to be further evaluated. The aerosol samples from the source regions have similar ratios to loess for crustal elements, but substantially different ratios for species from anthropogenic sources (e.g., K, P, V, Cr, Cu, Zn, Ni, and Pb), indicating that the aerosol samples from the geological-source-dominated environment are not a "pure" soil product as compared with loess.     

Winter and summer characteristics of airborne particles inside emperor Qin's Terra-Cotta Museum, China: a study by scanning electron microscopy-energy dispersive X-ray spectrometry

Day- and nighttime total suspended particulate matter was collected inside and outside Emperor Qin's Terra-Cotta Museum in winter and summer 2008. The purpose was to characterize the winter and summer differences of indoor airborne particles in two display halls with different architectural and ventilation conditions, namely the Exhibition Hall and Pit No. 1. The morphology and elemental composition of two season samples were investigated using scanning electron microscopy and energy dispersive X-ray spectrometry. It is found that the particle size, particle mass concentration, and particle type were associated with the visitor numbers in the Exhibition Hall and with the natural ventilation in Pit No. 1 in both winter and summer. Evident winter and summer changes in the composition and physicochemical properties of the indoor suspended particulate matters were related to the source emission and the meteorological conditions. Particle mass concentrations in both halls were higher in winter than in summer. In winter, the size of the most abundant particles at the three sites were all between 0.5 and 1.0 microm, whereas in summer the peaks were all located at less than 0.5 microm. The fraction of sulfur-containing particles was 2-7 times higher in winter than in summer. In addition to the potential soiling hazard, the formation and deposition of sulfur-containing particles in winter may lead to the chemical and physical weathering of the surfaces of the terra-cotta statues.     

Assessing the Eutrophication of Shengzhong Reservoir Based on Grey Clustering Method

Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water enviromnent to establish a relatively complete model suitable for the reservoir eutrophication evaluation and appropriately evaluate the quality of reservoir water, providing evidence for reservoir management. According to China＇s lakes and reservoir eutrophication criteria and the characteristics of China＇s eutrophication, as well as certain evaluation indices, the degree of eutrophication is classified into six categories with the utilization of grey classified whitening weight function to represent the boundaries of classification, to determine the clustering weight and clustering coefficient of each index in grey classifications, and the classification of each clustering object. The comprehensive evaluation of reservoir eutrophication is established on such a foundation, with Sichuan Shengzhong Reservoir as the survey object and the analysis of the data attained by several typical monitoring points there in 2006. It is found that eutrophication of Tiebian Power Generation Station, Guoyuanchang and Dashiqiao Bridge is the heaviest, Tielusi and Qinggangya the second, and Lijiaba the least. The eutrophication of this reservoir is closely relevant to the irrational exploitation in its surrounding areas, especially to the aggravation of the non-point source pollution and the increase of net-culture fishing. Therefore, it is feasible to use grey clustering in environment quality evaluation, and the point lies in the correct division of grey whitening function     

添加剩余活性污泥无害化处理含油钻屑

采用剩余活性污泥对废弃含油钻屑进行无害化处理。考察了加入剩余活性污泥后混合物料中微生物浓度、碱解氮含量、有效磷含量、总石油烃(TPH)含量和组分的变化,并对降解后混合物料的生物毒性进行了评价。实验结果表明:加入剩余活性污泥后,总细菌浓度保持在较高水平;碱解氮含量逐渐减少后保持稳定,有效磷含量在一定范围内波动,整体略有增加;剩余活性污泥的加入量为20%～60%(w)时, TPH去除率均达到74%以上,远高于未添加剩余活性污泥的对照组(28.8%);剩余活性污泥的添加能有效促进微生物对含油钻屑中TPH的降解及氮元素的转化,添加50%(w)以上的剩余活性污泥能使处理后含油钻屑的生物毒性更低,更有利于含油钻屑的无害化处理。