水中腐殖酸对高级氧化联用技术去除内分泌干扰物（DMP）的影响

使用腐殖酸模拟本底天然有机物进行试验,采用UV-H₂O₂、O₃、UV-O₃3种高级氧化工艺,研究了水中腐殖酸对3种高级氧化联用技术去除饮用水中内分泌干扰物(DMP)的影响.结果表明,UV-H₂O₂联用工艺氧化DMP的过程符合伪一级反应动力学,水中腐殖酸的存在对UV-H₂O₂联用工艺氧化DMP的影响非常大,伪一级反应的速率常数与本底TOC值的关系式为K=0.162 0[TOC]₀^{-0.817 1};同时水中腐殖酸对UV-O₃联用工艺氧化DMP的效果影响比较大,而总体上腐殖酸对O₃氧化DMP的去除影响不大.从效果分析知,在一定浓度腐殖酸本底条件下单独O₃氧化和UV-O₃联用工艺对DMP的氧化均以O₃分子对DMP的氧化起主导作用,当腐殖酸浓度变小,UV-O₃联用工艺体系中.OH自由基氧化DMP的重要性增大.水中腐殖酸对3种高级氧化工艺的影响程度顺序依次为:UV-H₂O₂>UV-O₃>O₃.     

从分子质量的变化分析有机物对GAC吸附内分泌干扰物(BPA)的影响

从分子质量分布的角度研究了水中有机物对颗粒活性炭(GAC)吸附双酚A(BPA)容量及吸附速率的影响.结果表明,相对于以去离子水为本底的BPA溶液来说,GAC吸附以滤后水、臭氧后出水和原水为本底的BPA溶液的Langmuir模型的最大吸附容量q_m值分别下降了29.95%、43.56%和44.44%,而其拟二级动力学模型的k₂值分别下降了43.05%、49.75%和56.38%.相对分子质量3 000以上,尤其是10 000以上的有机物堵塞GAC的二级微孔;3 000以下,尤其是1 000以下的有机物与BPA分子之间存在直接的竞争吸附,是导致GAC对BPA的吸附容量以及吸附速率下降的主要原因.     

测氧仪使用及维护中应注意的几个问题

测氧仪广泛用于石化行业的受限空间缺氧或富氧检测.在简要介绍测氧仪核心--伽伐尼氧气传感器工作原理的基础上,分析了影响毛细管式氧气传感器工作的主要因素,结合工作实践,提出了使用维护测氧仪的几条建议.     

安全评价对加油站的作用

1安全评价的含义 安全评价,就是以实现系统安全为目的,运用安全系统工程的原理和方法,对系统中存在的危险、有害因素进行辨识与分析,判断系统发生事故和职业危害的可能性及其严重程度,从而为制定防范措施和管理决策提供科学依据.     

QHSE内部审核与综合大检查整合的探讨

2002年3月,秦京输油气分公司被列为中国石油管道公司的QHSE管理体系试点单位之一.在近几年的QHSE管理体系运行过程中,分公司全体员工不断提高认识,坚持从领导做起、从机关做起、从培训做起、从每一项具体工作内容做起,认真推行QHSE管理体系,并积极探索QHSE管理体系与分公司管理实际有效结合的方法和途径.为解决QHSE管理体系与实际工作"两张皮"的现象,分公司提出了介业管理的"四个一"要求.     

Environmental impact of a coal combustion-desulphurisation plant: abatement capacity of desulphurisation process and environmental characterisation of combustion by-products

The fate of trace elements in a combustion power plant equipped with a wet limestone flue gas desulphurisation (FGD) installation was studied in order to evaluate its emission abatement capacity. With this aim representative samples of feed coal, boiler slag, fly ash, limestone, FGD gypsum and FGD process water and wastewater were analysed for major and trace elements using the following techniques: inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), ion chromatography (IC), ion selective electrode (ISE) and atomic absorption spectroscopy (AAS). Mass balances were established allowing to determine the element partitioning behaviour. It was found that, together with S, Hg, Cl, F, Se and As were those elements entering in the FGD plant primarily as gaseous species. The abatement capacity of the FGD plant for such elements offered values ranged from 96% to 100% for As, Cl, F, S and Se, and about 60% for Hg. The environmental characterisation of combustion by-products (boiler slag, fly ash and FGD gypsum) were also established according to the Council Decision 2003/33/EC on waste disposal. To this end, water leaching tests (EN-12457-4) were performed, analysing the elements with environmental concern by means of the aforementioned techniques. According to the leaching behaviour of combustion by-products studied, these could be disposed of in landfills for non-hazardous wastes.     

Particle size distributions of polycyclic aromatic hydrocarbons in rural and urban atmosphere of Tianjin, China

The size distributions of 16 polycyclic aromatic hydrocarbons (PAHs) and particle mass less than 10 microm in aerodynamic diameter (Dp) were measured using a nine-stage low-volume cascade impactor at rural and urban sites in Tianjin, China in the winter of 2003-2004. The particles exhibited the trimodal distribution with the major peaks occurring at 0.43-2.1 and 9.0-10.0 microm for both urban and rural sites. The concentrations of the total PAH (sum of 16 PAH compound) at rural site were generally less than those of urban site. Mean fraction of 76.5% and 63.9% of the total PAH were associated with particles of 0.43-2.1 microm at rural and urban sites, respectively. Precipitation, temperature, wind speed and direction were the important meteorological factors influencing the concentration of PAHs in rural and urban sites. The distributions of PAHs concentration with respect to particle size were similar for rural and urban samples. The PAHs concentrations at the height of 40 m were higher than both of 20 and 60 m at urban site, but the mass median diameter (MMD) of total PAH increased with the increasing height. The mid-high molecular weight (278 >or= MW >or= 202) PAHs were mainly associated with fine particles (Dp or=MW >or=178) PAHs were distributed in both of fine and coarse particle. The fraction of PAHs associated with coarse particles (Dp>2.1 microm) decreased with increasing molecular weight. The relatively consistent distribution of PAHs seemed to indicate the similar combustion source of PAHs at both of rural and urban sites. The fine differences of concentration and distribution of PAHs at different levels at urban site suggested that the different source and transportation path of particulate PAHs.     

Preparation of spherical iron nanoclusters in ethanol-water solution for nitrate removal

In this study, a higher surface area spherical nanoscale zero valent iron (HNZVI) cluster (80 nm, 54.25 m(2)g(-1)) was synthesized in ethanol-water mixed solvent in the presence of dispersion agent of polyglycol (PEG). At the same time, a lower surface area nanoscale zero valent iron (LNZVI) particle (80 nm, 8.08 m(2)g(-1)) was also prepared with only de-ioned water as reaction media. Their structures, compositions and physical properties were characterized by transmission electron microscope (TEM), X-ray diffractometer (XRD), inductively coupled plasma atomic emission spectrophotometer (ICP-AES), and Brunauer-Emmett-Teller (BET) surface area analyzer and the results obtained for these two kinds of nanoscale iron were compared with each other and also with those reported in the literatures. The HNZVI clusters seemed to be accumulated by smaller iron particles (<10 nm). At the same time, whiskers were formed in the final produce. Reactivity of the HNZVI was affirmed via denitrification of nitrate. The factors controlling the reduction of nitrate, such as pH, dissolved oxygen (DO), iron content as well as the initial nitrate concentration were also discussed. Finally, kinetic analysis revealed that chemical reduction of nitrate by HNZVI could not be described by the first- or pseudo-first-order kinetic model.     

Pesticides in the groundwater of a spring draining a sandy aquifer: temporal variability of concentrations and fluxes

A 250 ha agricultural catchment has been characterized with respect to its hydrogeology and groundwater contamination by pesticides from October 1999 to August 2004. Five years after the ending of atrazine (At) application, used since the sixties, At and deethylatrazine (DEA) are still systematically quantified at the outlet of the watershed with concentrations from 0.07 to 0.43 microg l(-1) for At, and between 0.14 and 1.16 microg l(-1) for DEA. Isoproturon and chlortoluron are detected in only one (0.3 microg l(-1)) and two (0.7 and 2.0 microg l(-1)) of the 124 semi-monthly samples, respectively. DEA concentrations can be very different between two samples with a 15-day time step. The annual mean exported fluxes of cumulated At and DEA are stable, which indicates a long time transfer in the unsaturated or saturated zone with a progressive leaching of the stock of At and DEA probably accumulated in the soil and the vadose zone. These fluxes, between 0.90% and 2.82% of the annual mean dose of At applied before 1999, similar to those calculated in several studies at the bottom of the root zone, could be explained by low adsorption and degradation properties of At and DEA in the unsaturated and saturated zone.     

Accumulation and distribution of polycyclic aromatic hydrocarbons in rice (Oryza sativa)

Various tissues of rice plants were sampled from a PAH contaminated site in Tianjin, China at different growth stages of the ripening period and analyzed for PAHs. PAHs were much higher in roots than in the exposed tissues. Grains and internodes accumulated much smaller amounts of PAHs than leaves, hulls or ear axes. No specific gradient trends along roots, stem, ear axes, and grains were observed, suggesting that systematic translocation among them is unlikely. Over the ripening period, PAH concentrations were increased in rice roots and decreased in most above-ground tissues. Significant correlations between PAH and lipid contents can only be observed during full mature stage. The spectra of individual PAH compounds in rice organs including roots were similar to those in air, rather than those in soil. There was also a significant correlation between bioconcentration factor (BCF, plant over air) and octanol/air partitioning coefficient (Koa).