用废弃印刷线路板制备粒状活性炭

以废旧印刷线路板非金属分离物为前躯体,经热解、成型、炭化和水蒸汽活化制备粒状活性炭.研究了热解温度对残碳收率的影响,煤焦油配比对成型碳强度的影响,活化反应条件对活性炭烧蚀率、比表面积和碘吸附值的影响.结果表明,随着热解温度的提高残碳收率下降;随着煤焦油配比增大,成型碳的强度呈现先增大后减少的趋势,成型碳机械强度最大时的...     

包气带土壤对石油烃的截留作用研究

包气带土壤对地表污染物的截留作用是地下水免受污染的一道天然屏障.土壤截留污染物的能力对地下水石油烃污染的治理起着关键作用,在对实际污染场地进行调查研究的基础上,采用土柱淋滤、吸附/解吸、石油挥发等室内模拟实验,研究包气带土壤对石油烃的截留作用及其影响因素.结果表明,细砂、中砂和粗砂3种土壤对石油烃的截留率分别为81.0...     

Release of hexachlorocyclohexanes from historically and freshly contaminated soils in China: implications for fate and regulation

Hexachlorocyclohexanes (HCHs) were produced and used in large quantity worldwide and are common soil pollutants. In this study, desorption of α-HCH and γ-HCH from two soil samples collected from a historical pesticide plant in Tianjin, China, was examined. As a comparison, desorption of freshly sorbed γ-HCH was examined, using five typical Chinese soils. Strong resistant desorption was observed for both historically contaminated and freshly contaminated soils, and desorption results were well modeled with a biphasic desorption isotherm. The unique thermodynamic characteristics associated with the desorption-resistant fraction indicated that physical constraint within soil organic matrices was likely the predominant mechanism controlling resistant desorption. Resistant desorption could have significant effects on fate and exposure of HCHs in soil environment. More accurate biphasic desorption models that take into account of the resistant desorption can be used to facilitate regulating, management and remediation of HCH-contaminated sites.     

水对公路工程的危害及公路建设对水环境的影响

水对公路的路基、路面、隧道等结构都会产生危害,而公路建设也会对沿线的地下水环境产生影响。进行公路排水对提高使用道路的寿命和服务质量有积极的作用,但也应考虑公路建设对地下水和地表水环境的影响。     

PM<Subscript>10</Subscript> emissions from industrial coal-fired chain-grate boilers

Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a Dekati® Low Pressure Impactor were applied to determine mass and number size distributions of PM₁₀ at the inlet and the outlet of the particulate emission control devices at six coalfired chain-grate boilers. The mass size distribution of PM₁₀ generated from coal-fired chain-grate boilers generally displays a bimodal distribution that contains a submicron mode and a coarse mode. The PM in the submicron mode for burning with raw coal contributes to 33% ± 10 % of PM₁₀ emissions, much higher than those for pulverized boilers. And the PM in the submicron mode for burning with briquette contributes up to 86 % of PM₁₀ emissions. Multiclones and scrubbers are not efficient for controlling PM10 emission. Their average collection efficiencies for sub-micron particle and super-micron particle are 34% and 78%, respectively. Operating conditions of industrial steam boilers have influence on PM generation. Peak of the submicron mode during normal operation period is larger than the start-up period.

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Physiological and molecular responses of the earthworm <Emphasis Type="Italic">Eisenia fetida</Emphasis> to polychlorinated biphenyl contamination in soil

Polychlorinated biphenyls (PCBs) are a class of man-made organic compounds ubiquitously present in the biosphere. In this study, we evaluated the toxic effects of different concentrations of PCBs in two natural soils (i.e. red soil and fluvo-aquic soil) on the earthworm Eisenia fetida. The parameters investigated included anti-oxidative response, genotoxic potential, weight variation and biochemical responses of the earthworm exposed to two different types of soils spiked with PCBs after 7 or 14 days of exposure. Earthworms had significantly lower weights in both soils after PCB exposure. PCBs significantly increased catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) activity in earthworms exposed to either soil type for 7 or 14 days and decreased the malondialdehyde (MDA) content in earthworms exposed to red soil for 14 days. Of the enzymes examined, SOD activity was the most sensitive to PCB stress. In addition, PCB exposure triggered dose-dependent coelomocyte DNA damage, even at the lowest concentration tested. This response was relatively stable between different soils. Three-way analysis of variance (ANOVA) showed that the weight variation, anti-oxidant enzyme activities, and MDA contents were significantly correlated with exposure concentration or exposure duration (P < 0.01). Furthermore, weight variation, CAT activity, and SOD activity were significantly affected by soil type (P < 0.01). Therefore, the soil type and exposure time influence the toxic effects of PCBs, and these factors should be considered when selecting responsive biomarkers.     

石化企业浮顶罐大呼吸损耗核算方法分析

石化企业储罐无组织排放挥发性有机物(VOCs)带来严重的环境问题和油品损耗问题,以浮顶罐的大呼吸损耗为代表。在概述浮顶罐大呼吸损耗机理的基础上,以北京某石化企业的甲苯内浮顶罐为基准案例,对国内外4种核算公式进行了对比分析,考察了影响浮顶罐大呼吸损耗的因素,并提出有效的减耗措施。结果表明:采用我国推荐的公式进行核算更符合我国实际,需建立和完善以我国有机液体理化参数和储罐构造为基准的核算方法和软件;影响浮顶罐大呼吸损耗的主要因素包括油品性质、周转量、罐体直径、罐壁黏附系数等,其中罐壁黏附系数为关键影响因素。     

SGA对垃圾焚烧飞灰中重金属的固化性能研究简

根据EPA 1311、HJ/T 299-2007、HJ/T 300-2007和HJ 557-2009等国内外不同标准,研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性,探讨了六硫代胍基甲酸（sixthio guanidine acid,SGA）、二甲基二硫代氨基甲酸盐（sodium dimethyl dithio carbamate,SDD）和Ca（OH）₂浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明,随着浸提液pH的降低,该厂焚烧飞灰中大部分金属元素的浸出量增大,焚烧飞灰浸出液中的Cd、Ni、Pb和Zn浓度分别超过国家危险废物鉴别标准（GB5085.3-2007）规定值的4.75倍、1.47倍、6.72倍和2.20倍,属于危险废弃物,必须进行稳定化处理。当固化剂SGA加入量为0.1 mol/kg时,稳定化后的重金属浸出浓度已经低于危险废物鉴别标准,且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）₂;当固化剂SGA、SDD和Ca（OH）₂加入量为0.5 mol/kg时,稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB 5085.3-2007）中的规定值。与SDD和Ca（OH）₂相比,SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

高氨废水短程硝化特性简

采用SBR装置,针对高氨废水的特点,在高氨条件下,以高氨低氧为转化手段,实现高氨废水短程硝化过程中亚硝化菌的驯化与积累。控制温度为28~31℃,曝气量为15~60 L/h,pH控制在7.8~8.2的条件下连续运行78 d。实验结果表明,运行11 d后实现了短程硝化,从11 d至78 d属于系统氨氮负荷提高期。在运行过程中,氨氮污泥负荷从开始的0.023 kg/（kg·d）逐步上升为0.3 kg/（kg·d）,最高时达到0.34 kg/（kg·d）,此时氨氮去除率仍维持90%以上。为观察驯化后短程硝化菌的形态,取驯化好的污泥进行电镜扫描,结果表明,污泥中的细菌形态主要以球状菌为主。     

An effective utilization of the slag from acid leaching of coal-waste: Preparation of water glass with a low-temperature co-melting reaction

This paper presents an effective utilization of slag from acid leaching of coal-waste with a novel approach, namely low-temperature co-melting method, for preparation of sodium silicate (Na₂O·nSiO₂) using slag from acid leaching of coal-waste as feedstock. It is very interesting that the co-melting reaction temperature of the mixture of Na₂CO₃ and the feedstock (50?100 μm) was as low as 850 °C, which was significantly lower than the temperature used in traditional sodium silicate production (1400 °C). The optimum SiO₂/Na₂O ratio was identified as 7:3 according to the results of thermogravimetry–differential scanning calorimetry (TGA-DSC), ICP-AES, and X-ray diffraction (XRD) analyses. In this condition, the main product was sodium disilicate (Na₂O·2SiO₂), with water solubility of 85.0%. More importantly, the impurities such as aluminum in the feedstock, which had adverse effect on subsequent treatment, were concentrated almost completely in the filter residue as insoluble sodium alumunosilicates, i.e., Na(Si₂Al)O₆·H₂O. The lower co-melting temperature of this process demonstrates a significant energy-saving opportunity and thus a promising approach for highly effective utilization of coal-waste.

Implications:Recently, alumina extraction from coal-waste has been extensively investigated and industrial applied in China. However, the slag-containing silica generated from the acid leaching process of coal-waste led to a secondary pollution, which hindered large-scale production. The proposed low-temperature co-melting method for preparation of sodium silicate (Na₂O·nSiO₂) using slag from acid leaching of coal-waste as feedstock indicated that it is an efficient approach for the recovery of silica from the acid-leached slag of coal-waste with minimal environmental impact.