Fe-Mt三维粒子电极体系去除水中亚甲基蓝

以铁改性蒙脱石(Fe-Mt)制备粒子电极,探究了其在三维电极体系中的催化性能。通过SEM-EDS和XRD对Fe-Mt粒子电极进行了形貌和物相表征,分析了不同反应条件(pH、投加量、槽电压等)对亚甲基蓝去除率的影响,进一步通过自由基抑制实验、H₂O₂的产生量以及总溶解性铁离子浓度检测探讨了Fe-Mt粒子电极对亚甲基蓝的氧化去除机理。结果表明,Fe-Mt粒子电极能够拓宽pH的有效作用范围,在pH=3.0、电压为5 V、粒子电极投加量为10 g∙L⁻¹条件下,较二维电化学体系亚甲基蓝去除率提高了约25%。Fe-Mt粒子电极能够直接或间接催化H₂O₂以产生羟基自由基,并结合吸附-氧化降解耦合机制强化了亚甲基蓝去除率。以上研究结果可为拓宽以蒙脱石为基材的催化材料在高级氧化体系的应用提供参考。     

Lipid peroxidation of kidney of the turtle Mauremys reevesii caused by cadmium

Environmental Science and Pollution Research - This research was designed to investigate lipid peroxidation of the kidney of turtle (Mauremys reevesii) caused by cadmium. Turtles were injected...     

Combustion sources of particles: 2. Emission factors and measurement methods

Emissions from the combustion of biomass and fossil fuels are a significant source of particulate matter (PM) in ambient outdoor and/or indoor air. It is important to quantify PM emissions from combustion sources for regulatory and control purposes in relation to air quality. In this paper, we review emission factors for several types of important combustion sources: road transport, industrial facilities, small household combustion devices, environmental tobacco smoke, and vegetation burning. We also review current methods for measuring particle physical characteristics (mass and number concentrations) and principles of methodologies for measuring emission factors. The emission factors can be measured on a fuel-mass basis and/or a task basis. Fuel-mass based emission factors (e.g., g/kg of fuel) can be readily used for the development of emission inventories when the amount of fuels consumed are known. Task-based emission factors (g/mile driven, g/MJ generated) are more appropriate when used to conduct comparisons of air pollution potentials of different combustion devices. Finally, we discuss major shortcomings and limitations of current methods for measuring particle emissions and present recommendations for development of future measurement techniques.     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

Zn/Fe体系湿法催化氧化高效脱除沼气中H2S的研究

提出了Zn/Fe体系湿法催化氧化脱除沼气中H₂S新工艺,阐述了反应机理、实验装置和工艺流程,考察了各单因素操作条件对H₂S脱除效率的影响,在此基础上进行的综合条件实验,脱硫效率都维持在99.6%以上,净化后沼气中H₂S含量低于国家标准。过程不消耗任何化工原料,不产生二次污染,体系无降解问题。     

厌氧消化数学模型ADM1的研究及应用进展

自2002年国际水协厌氧消化工艺数学模型课题组推出厌氧消化模型ADM1以来,随着研究与应用的深入,该模型不断发展完善,已经被证明是指导厌氧消化工艺设计与模拟、预测厌氧消化过程及结果的可靠工具。总结了近年ADM1在生化反应动力学、不同反应器类型、不同发酵底物、厌氧消化微生物种群等方面的拓展与改进研究,简单介绍了该模型在厌氧消化实际工程中的应用及模型存在的缺陷和不足。     

Levels, sources and health risks of carbonyls and BTEX in the ambient air of Beijing, China

The atmospheric concentrations of carbonyls and BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) were measured simultaneously at a same sampling site in Beijing from September 2008 to August 2010. The average concentrations of the total measured carbonyls during autumn, winter, spring, and summer were 37.7, 31.3, 39.7, 50.5 μg/m³, respectively, and maximal values for their diurnal variations usually happened at noontime. In contrast to carbonyls, the average concentrations of the total measured BTEX during the four seasons were 27.2, 31.9, 23.2, 19.1 μg/m³, respectively, and minimal values for their diurnal variations always occurred in the early afternoon. The average concentration for carbonyls increased about 24% from September 2008-August 2009 to September 2009-August 2010, for BTEX, increased about 15%. Integrated life time cancer risks for three carcinogens (benzene, formaldehyde and acetaldehyde) in Beijing exceeded the value of 1E-06, and the hazard quotient (HQ) of non-cancer risk of exposure to formaldehyde exceeded unity.     

不同深度处理工艺再生水中余氯衰减规律及溶解性有机物变化特性比较

考察了余氯在不同深度处理工艺再生水中的衰减规律,并利用紫外-可见吸收差光谱和三维荧光光谱对余氯衰减过程的有机物变化进行了初步解析.结果表明,再生水中的余氯衰减迅速,加氯前0.5 h内的氯消耗占8 h内氯消耗的50%以上.混凝出水水样的余氯衰减速率大于超滤出水和臭氧出水.加氯后,混凝出水和超滤出水的紫外-可见吸收差光谱在230 nm和280 nm附近出现特征峰,表明余氯衰减过程中,水中具有不饱和键和生色团的物质被破坏.臭氧出水在波长230 nm附近出现特征峰.加氯使再生水的荧光强度减弱,混凝出水中腐殖质类物质荧光强度的降低程度大于超滤出水和臭氧出水,表明该类物质可能是影响余氯衰减速率的主要物质.     

磷钼酸铵-聚乙烯醇复合材料的制备及其对水中Cs+的吸附性能研究

利用磷钼酸铵、聚乙烯醇和正硅酸四乙酯合成一种新型复合材料（AMP-PVA）,运用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射（XRD）、X射线光电子能谱（XPS）和热重分析仪（TG-DSC）等对AMP-PVA进行结构和形貌表征.同时,探究了不同初始浓度、pH、时间等因素对AMP-PVA特异性吸附Cs⁺性能的影响,并结合等温吸附曲线、吸附动力学等对AMP-PVA的吸附机制进行探讨.结果表明,AMP-PVA可在pH=2~11范围内使用,耐酸性能良好,且在35 ℃、pH=7.7、初始Cs⁺浓度为200 mg·L^-1的条件下达到最大吸附量109.56 mg·g^-1;吸附过程以自发的、吸热的、可持续的化学吸附为主,符合Freundlich等温吸附模型和准二级动力学模型,并伴随着内扩散和Boyd模型的特征;AMP-PVA主要作用机制为Cs⁺与AMP中的NH₄⁺发生离子交换.     

长江口九段沙湿地自然保护的探讨

九段沙是长江口新生沙岛，在调研其湿地生态环境和自然演变趋势基础上，尽快设立九段沙自然保护区已是各方共识，但对其而言，一方面已有大型工程的影响，另一方面滩地的冲蚀可能使高级群落－芦苇的分布面积减少，因此提出，在保护湿地初期建造，低堤不至于影响湿地的自然演变过程，而有利于保护高级群落和局部高潮滩的增速。