一起立式锅炉爆炸事故原因分析及隐患排查

采用现场勘察、光谱分析和金相检验等方法对一起立式锅炉爆炸事故进行原因分析,发现该锅炉制造时存在严重未焊透的设备缺陷和其他使用管理方面的问题。为此制定了超声波检测工艺,对本地区同一制造厂生产的在用锅炉进行隐患排查。对排查发现存在严重制造缺陷的锅炉进行现场维修或召回,对排查发现的使用管理方面的问题也一并跟踪整改。     

改性TiO_2光催化降解三苯甲烷类污染物

以硫酸钛为原料采用水热法制备了掺Fe3＋TiO2晶体粉末,采用X射线衍射仪（XRD）对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3＋TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3＋TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood（L-H）动力学模型描述,其表观反应速度常数（k）的大小顺序为：溴酚蓝〈甲基绿〈甲基蓝〈孔雀石绿〈甲基紫〈碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。     

降流式厌氧悬浮填料床工艺特性分析

厌氧生物技术能在无氧条件下,通过厌氧微生物的新陈代谢将废水中的有机物转化为无机物,同时产生具有能源回收价值的甲烷,并减少温室气体(CO2)的排放,符合节能环保的原则和发展趋势.在回顾厌氧技术以及厌氧反应器发展的基础上,从现代厌氧反应器的发展理念角度分析了新型厌氧反应器-降流式厌氧悬浮填料床(DASB)的工艺特性.降流式厌氧悬浮填料床在生物量的保持、微生物的多级多相和推流流态等方面较好地符合了新型现代厌氧反应器的发展要求,结构、运行简单,具有较好的处理效果,是中国农村污水处理或预处理的较佳选择.     

Seasonal variation on size distribution and concentration of PAHs in Guangzhou city, China

Size distribution aerosol samples were collected at an urban location of Guangzhou in four seasons of 2003-2004 by a MOUDI (Micro-orifice Uniform Deposit Impactor). The particle loading (PM10: 80-397 microg m(-3)) was comparable with some other Asia cities; however, much higher than that of Western Europe and North America. Polycyclic aromatic hydrocarbons (PAHs) were measured by gas chromatography with mass selective detector (GC-MS). Seasonal effects on the size distribution of PAHs are presented. Bimode (accumulation and coarse mode) and unimode (accumulation mode) distributions were observed for low-molecule-weight and high-molecule-weight PAHs. A slight shift to larger particles was found for the accumulation mode in autumn and winter, compared with that of spring and summer. One explanation is that the longer aging process of PAHs in autumn and winter would result in volatilization from finer particles followed by condensation onto coarser particles. Another is there was mixing process of local emission with long-range transported aerosol in autumn and winter. The relative higher value of IcdP/(BghiP+IcdP) and lower value of BghiP/BeP in winter also give evidences to the mixing process. The level of PAHs concentration has been much elevated in recent years. This can be attributed to the fast growth of motor vehicle and energy consumption.     

SO2 允许排放量分配技术方法的研究

 将SO₂ 排放源分成电厂、工业、供热及民用4 类燃煤源,分别选择不同的指标,综合分析各污染源的SO₂ 排放绩效水平,结合当地的环境质量状况、发展规划、国家和地方的有关产业政策和环境保护政策以及不同行业类型排放源的生产特点和排污水平,设定各类燃煤源应达到的排放绩效标准,利用ISC3 环境空气质量模型,基于基准排放因子及环境综合调节系数,确定各污染源的最终允许排放量.以天津市为例,电厂燃煤源、供热污染源、工业燃煤源的SO₂ 年允许排放量分别为1.25×10⁵,1.24×10⁴,4.12×10⁴t,削减率分别为14.4%,25.8%,27.9%.     

Hexabromocyclododecane and tetrabromobisphenol A in sediments and paddy soils from Liaohe River Basin, China: Levels, distribution and mass inventory

Hexabromocyclododecane(HBCD) and tetrabromobisphenol A(TBBPA) are two kinds of brominated flame retardants and widely present in the environment and biota. The levels,spatial distributions and mass inventories of HBCD and TBBPA were investigated in sediments and paddy soils from the Liaohe River Basin in northeast China. The concentrations of ΣHBCD and TBBPA were in the range of not detected(nd) to 4.02 ng/g dry weight(dw) and 0.03 to 4.06 ng/g dw, respectively. γ-HBCD was dominated in sediments,while the abundance of α-HBCD was relatively high in paddy soils. The spatial distributions of HBCD and TBBPA in surface sediments and paddy soils indicated that the local point-input was their major source. The significant correlation between total organic carbon(TOC) contents and the HBCD levels suggested that TOC content also exerted an influence on the distribution of HBCD in sediments. Meanwhile, it was found that the irrigation with river water was not the major transportation pathway of HBCD and TBBPA in paddy soils. Based on the study, it was estimated that there were about 1.67 tons HBCD and 2.20 tons TBBPA deposited into sediments of the Liaohe River system every year. The total mass inventories of HBCD and TBBPA in sediments were far higher than that in paddy soils.     

乌鲁木齐市环境空气中TSP和PM10来源解析

2002年,在乌鲁木齐市5个采样点分别采集了环境空气中的总悬浮颗粒物(TSP)和可吸入颗粒物(PM10).用化学质量平衡 (CMB)受体模型和二重源解析技术解析了TSP和PM10的来源,结果表明,各主要源类对TSP的分担率依次为扬尘34%、燃煤尘26%、建筑水泥尘10%、硫酸盐8%、土壤风沙尘7%、机动车尾气尘6%、钢铁尘2%、硝酸盐1%、其它6%;对PM10的分担率依次为扬尘30%、燃煤尘28%、建筑水泥尘11%、硫酸盐10%、机动车尾气尘8%、土壤风沙尘8%、硝酸盐1%、其它3%.     

生物陶粒处理深圳水库水的试验研究

利用生物陶粒对深圳水库水进行了生物预处理现场试验研究,试验结果表明,生物陶粒能有效地降低水中的ＮＯ２－Ｎ、ＮＨ３－Ｎ、ＯＣ、浊度、色度、Ｍｎ和藻类,在工作滤速为４ｍ／ｈ,气水比为１：１的条件下平均去除率分别为９０．８％,８４％、２１．４％６２％、４７％、８９％和６８％,是解决水源水微污染问题有效的预单元工艺。     

Roles of manganese oxides in degradation of phenol under UV-Vis irradiation: Adsorption, oxidation, and photocatalysis

The effect of crystal structure on photocatalytic activities of manganese oxides and underlying reaction mechanism were investigated.     

Sulfur speciation and bioaccumulation in camphor tree leaves as atmospheric sulfur indicator analyzed by synchrotron radiation XRF and XANES

Analyzing and understanding the effects of ambient pollution on plants is getting more and more attention as a topic of environmental biology.A method based on synchrotron radiation X-ray fluorescence and X-ray absorption near edge structure spectroscopy was established to analyze the sulfur concentration and speciation in mature camphor tree leaves (CTLs),which were sampled from 5 local fields in Shanghai,China.Annual SO2 concentration,SO42-concentration in atmospheric particulate,SO42-and sulfur concentration in soil were also analyzed to explore the relationship between ambient sulfur sources and the sulfur nutrient cycling in CTLs.Total sulfur concentration in mature camphor tree leaves was 766-1704 mg/kg.The mainly detected sulfur states and their corresponding compounds were +6 (sulfate,include inorganic sulfate and organic sulfate),+5.2 (sulfonate),+2.2 (suloxides),+0.6 (thiols and thiothers),+0.2 (organic sulfides).Total sulfur concentration was strongly correlated with sulfate proportion with a linear correlation coefficient up to 0.977,which suggested that sulfur accumulated in CTLs as sulfate form.Reduced sulfur compounds (organic sulfides,thiols,thioethers,sulfoxide and sulfonate) assimilation was sufficed to meet the nutrient requirement for growth at a balanced level around 526 mg/kg.The sulfate accumulation mainly caused by atmospheric sulfur pollution such as SO2 and airborne sulfate particulate instead of soil contamination.From urban to suburb place,sulfate in mature CTLs decreased as the atmospheric sulfur pollution reduced,but a dramatic increase presented near the seashore,where the marine sulfate emission and maritime activity pollution were significant.The sulfur concentration and speciation in mature CTLs effectively represented the long-term biological accumulation of atmospheric sulfur pollution in local environment.