PX项目环境风险分析

系统分析了PX项目的环境风险,结果表明:PX项目装置各单元均不是危险化工工艺单元,安全设施和污染治理水平相较于其它石油化工装置更高,但是基于装置物料的危险性和生产企业的高环境敏感度,PX项目的环境保护工作面临较大挑战。在此基础上,剖析了目前国内PX项目存在的主要环境风险问题,并提出相应的对策建议。     

非一阴离子表面活性剂对PAHs的增溶作用及无机盐的强化效果研究

文章研究了几种非离子和阴离子表面活性剂在单一或混合条件下对多环芳烃（PAHs）萘和菲的增溶作用,并分析了无机盐对表面活性剂增溶PAHs的强化效果.结果表明,在相同浓度条件下,非离子表面活性剂对菲和萘的增溶效果均高于阴离子表面活性剂,其增溶能力大小顺序为：Tween 80 ＞TX-100＞ Tween 20＞ SDS＞SDBS.将非离子与阴离子表面活性剂混合后,对萘和菲的增溶作用大于单一阴离子表面活性剂而小于单一非离子表面活性剂,且增溶效果随着非离子表面活性剂比例的增加而增大.低浓度（0.03 mol/L）的NaCl和Na2SO4可大幅度促进表面活性剂对萘和菲的增溶效果,但随着无机盐浓度的提高,对增溶效果的促进作用不明显.     

重庆铁山坪森林土壤汞释放通量的影响因子研究

对位于重庆铁山坪的马尾松林下的山地黄壤进行表层土壤(0~5 cm)的原状采集,并在实验室中进行控制实验,利用通量箱法测量原状土块表面的汞释放通量,以研究环境因子对土壤汞释放量的影响.结果表明,土壤汞释放量与辐射强度呈显著的正相关,在相同的空气温度和土壤含水量等条件下,土壤汞释放量在光下是遮阳条件下的3~9倍.不过,由于林下土壤常处于背阴状态,可能遮阳条件更能代表白天林下土壤汞的排放情况.土壤汞释放量存在明显的季节变化,夏季>春秋季>冬季,空气温度与土壤汞释放呈正相关.在低温下土壤汞释放量很低,土壤含水量影响较弱,而在高温时土壤含水量增加能明显促进土壤汞释放.枯落物的移除会显著降低土壤汞释放通量,主要原因可能是枯落物的汞含量较高并易于还原.土壤汞释放量在一天内也存在明显的衰减趋势,表明土壤表层的汞含量可能是森林土壤汞释放的重要限制因素.本研究测得森林土壤汞释放通量(白天)为:夏季(14.3±19.6)ng·(m2·h)-1、春秋季(3.50±5.36)ng·(m2·h)-1、冬季(1.48±3.27)ng·(m2·h)-1,以上稳态测试结果可能高估了实际的汞排放量.     

Enhancing plant-microbe associated bioremediation of phenanthrene and pyrene contaminated soil by SDBS-Tween 80 mixed surfactants

The use of surfactants to enhance plant-microbe associated dissipation in soils contaminated with polycyclic aromatic hydrocarbons(PAHs) is a promising bioremediation technology. This comparative study was conducted on the effects of plant-microbe treatment on the removal of phenanthrene and pyrene from contaminated soil, in the presence of low concentration single anionic, nonionic and anionic-nonionic mixed surfactants. Sodium dodecyl benzene sulfonate(SDBS) and Tween 80 were chosen as representative anionic and nonionic surfactants, respectively. We found that mixed surfactants with concentrations less than 150 mg/kg were more effective in promoting plant-microbe associated bioremediation than the same amount of single surfactants. Only about(m/m) of mixed surfactants was needed to remove the same amount of phenanthrene and pyrene from either the planted or unplanted soils, when compared to Tween 80. Mixed surfactants( 150 mg/kg) better enhanced the degradation efficiency of phenanthrene and pyrene via microbe or plant-microbe routes in the soils. In the concentration range of 60–150 mg/kg, both ryegrass roots and shoots could accumulate 2–3 times the phenanthrene and pyrene with mixed surfactants than with Tween 80. These results may be explained by the lower sorption loss and reduced interfacial tension of mixed surfactants relative to Tween 80, which enhanced the bioavailability of PAHs in soil and the microbial degradation efficiency. The higher remediation efficiency of low dosage SDBS-Tween 80 mixed surfactants thus advanced the technology of surfactant-enhanced plant-microbe associated bioremediation.     

Isolation, identification and arsenic-resistance of Acidithiobacillus ferrooxidans HX3 producing schwertmannite

Schwertmannite, a ubiquitous mineral present in iron oxyhydroxides formed in iron- and sulfate-rich acid media, favors incorporation of some toxic anions in its structure. We reported an iron-oxidizing bacterial strain HX3 from a municipal sludge that facilitates the formation of pure schwertmannite in cultures. Ferrous iron oxidation by the isolated strain HX3 was optimum at an initial pH of 2.0-3.3 and temperature of 28-35°C. Pure schwertmannite was found through bacterial oxidation of ferrous iron at an initial pH 2.8and temperature 28°C. Following 16 S rDNA gene sequence analysis the bacterial strain HX3 was identified as Acidithiobacillus ferrooxidans. The arsenic-resistance A. ferrooxidans HX3 showed the potential of environmental application in arsenic removal from the As（Ⅲ）- and iron-rich acid sulfate waters directly by As（Ⅲ） adsorption or the formation of schwertmannite in the environment.     

Atmospheric sulfur hexafluoride in-situ measurements at the Shangdianzi regional background station in China

We present in-situ measurements of atmospheric sulfur hexafluoride（SF6） conducted by an automated gas chromatograph–electron capture detector system and a gas chromatography/mass spectrometry system at a regional background site, Shangdianzi,in China, from June 2009 to May 2011, using the System for Observation of Greenhouse gases in Europe and Asia and Advanced Global Atmospheric Gases Experiment（AGAGE）techniques. The mean background and polluted mixing ratios for SF6 during the study period were 7.22 × 10-12（mol/mol, hereinafter） and 8.66 × 10-12, respectively. The averaged SF6 background mixing ratios at Shangdianzi were consistent with those obtained at other AGAGE stations located at similar latitudes（Trinidad Head and Mace Head）, but larger than AGAGE stations in the Southern Hemisphere（Cape Grim and Cape Matatula）. SF6 background mixing ratios increased rapidly during our study period, with a positive growth rate at 0.30 × 10-12year-1. The peak to peak amplitude of the seasonal cycle for SF6 background conditions was 0.07 × 10-12, while the seasonal fluctuation of polluted conditions was 2.16 × 10-12. During the study period, peak values of SF6 mixing ratios occurred in autumn when local surface horizontal winds originated from W/WSW/SW/SWS/S sectors, while lower levels of SF6 mixing ratios appeared as winds originated from N/NNE/NE/ENE/E sectors.     

Characteristics of secondary inorganic aerosol and sulfate species in size-fractionated aerosol particles in Shanghai

Sulfate, nitrate and ammonium(SNA) are the dominant species in secondary inorganic aerosol, and are considered an important factor in regional haze formation. Size-fractionated aerosol particles for a whole year were collected to study the size distribution of SNA as well as their chemical species in Shanghai. SNA mainly accumulated in fine particles and the highest average ratio of SNA to particulate matter(PM) was observed to be 47% in the fine size fraction(0.49–0.95 μm). Higher sulfur oxidation ratio and nitrogen oxidation ratio values were observed in PM of fine size less than 0.95 μm. Ion balance calculations indicated that more secondary sulfate and nitrate would be generated in PM of fine size(0.49–0.95 μm). Sulfur K-edge X-ray absorption near-edge structure(XANES) spectra of typical samples were analyzed. Results revealed that sulfur mainly existed as sulfate with a proportion(atomic basis) more than 73% in all size of PM and even higher at 90% in fine particles. Sulfate mainly existed as(NH4)2SO4 and gypsum in PM of Shanghai. Compared to non-haze days, a dramatic increase of(NH4)2SO4 content was found in fine particles on haze days only, which suggested the promoting impact of(NH4)2SO4 on haze formation. According to the result of air mass backward trajectory analysis, more(NH4)2SO4 would be generated during the periods of air mass stagnation. Based on XANES, analysis of sulfate species in size-fractionated aerosol particles can be an effective way to evaluate the impact of sulfate aerosols on regional haze formation.     

石油污染物对海底微生物燃料电池性能的影响及加速降解效应

海底石油污染物在缺氧环境下导致其生物降解过程缓慢,对海洋环境造成长期危害.本文利用海底微生物燃料电池(BMFCs)原理,尝试通过电催化作用提高海底石油污染物的降解速率.对比测试了含油电池装置(BMFCs-A)与无油电池装置(BMFCs-B)的电化学性能,研究了石油污染物对电池性能的影响;比较了含油通路(BMFCs-A)和断路状态下(BMFCs-C)的石油降解率和细菌聚集量,分析了BMFCs对石油污染物降解的加速作用.结果表明,BMFCs-A和BMFCs-B阳极的交换电流密度分别为1.37×10-2A·m-2和1.50×10-3A·m-2,最大输出功率密度分别是105.79 m W·m-2和83.60 m W·m-2,BMFCs-A装置的抗极化能力增强,交换电流密度提高近9倍,最大输出功率密度提高1.27倍.BMFCs-A和BMFCs-C阳极表面的异养菌数量分别是(66±3.61)×107CFU·g-1和(7.3±2.08)×107CFU·g-1,细菌数量增加了8倍,高的异养菌数量导致石油降解加速进行,BMFCs的石油降解率是自然条件下的18.7倍.BMFCs在电化学性能提高的同时,加速石油污染物的降解.本文同时提出了一种海底微生物燃料电池对石油污染物加速降解的新模式.     

Effects of extracellular polymeric substances on aerobic granulation in sequencing batch reactors

The effects of extracellular polymeric substances on aerobic granulation in sequencing batch reactors were investigated by evaluating the content and compositions of extracellular polymeric substances, and the relationship between extracellular polymeric substances composition and surface properties of glucose-fed aerobic granules. The results showed that extracellular polymeric substances could affect surface properties of cells, such as surface charge and hydrophobicity, enhance polymeric interaction and promote aerobic granulation. Moreover, extracellular polymeric substances were produced mainly in the exponential phase, and served as carbon and energy source in starvation phase during granulation process, thus regulating the growth of bacteria in the interior and exterior of granules, and maintaining the integrality of granules.     

Multiple Effects of Energy Issues and Countermeasures： A Case of Shandong Province

Energy is now becoming the bottleneck of urban and regional development. The paper takes Shandong Province, one of the most energy consuming provinces in China, as an example, uses quantity methods such as SPSS （Stastics Package for Social Science） cluster sampling and regression analysis, and applies quantity analysis, to analyze the situation of energy issues in Shandong province. The conflicts between the quick industrialization and increasing extensive economic development, between urban population and energy consuming per head, between the infinite energy consuming desire and the low level of managing system, and between the unstable world energy supply and the limited energy storage in China are the main factors of energy crisis in Shandong, which not only results in energy shortage, but also becomes the barrier of economic and social development. In order to ensure sufficient energy supply for Shandong province in the 21 st century, we should take countermeasures, such as changing the economic development model, pursuing a multiple and high quality energy strategy, improving the intensive urbanization strategy, and building a scientific energy system.