基于大气环境的固定源细颗粒物测试方法研究进展

国内对固定源细颗粒物研究还较为薄弱,主要是缺乏合适的测试方法.由于基于大气环境的稀释测试法可在一定程度上模拟烟气排放至大气环境的物理化学过程,所以该法正成为研究固定源细颗粒物排放特征的重要手段.本文对国内外基于大气环境的固定源细颗粒物测试方法进行了系统介绍与分析,指出该测试系统应向小型化、便携式方向发展,以满足不同浓度、不同湿度、不同温度固定源细颗粒物的测试需要.     

高湿烟气中超低浓度细颗粒物测试方法研究

总结和比较了国内外常用的颗粒物采样测试系统及方法,从颗粒物测量原理、采样方法的结构和特点、适用范围、误差来源等角度分析了采样系统的特点及准确性,并结合我国燃煤电厂脱硫塔、湿式静电除尘器出口等位置实际排放情况,提出适用于低浓度、高湿度条件下的超低浓度颗粒物的可靠测试方法.为燃煤电厂颗粒物排放浓度的准确测量和环保设备对颗粒物控制效果的运行和评估提供保证.     

微颗粒在表面粘附的力学模型

微颗粒粉尘对于工农业生产及人的身体健康都会造成危害,而微颗粒粘附数学模型是对其进行研究和控制的基础,有着十分重要的意义。微颗粒与表面粘附力学模型研究取得了很大的进展,作者通过在一些重要中外文数据库对微颗粒在表面粘附的力学模型研究成果进行了分析,这些粘附力主要是物理吸附力的范德华力、静电力、磁力、毛细作用力。在此基础上对各个力进行归纳、评述,并指出了各个模型的实际应用。对各种力学模型进行总结,然后以一个例子说明微颗粒粉尘在多种力同时作用时的力的简单合成情况,最后提出了本领域的研究展望。     

污染城市大气PM10单颗粒形态特征——以石家庄市为例

选择大气污染严重的石家庄市为北方污染城市代表,采集石市PM10颗粒物样品,运用扫描电镜和X射线能谱分析技术,观察分析单颗粒物形态特征。结果表明,污染城市大气PM10以块状颗粒物数量最多,来自表土风蚀的矿物颗粒;次为凝聚状颗粒和球状颗粒物,是人为源的标志;球粒可分为硅质小球、硅铝小球和铁质小球三类,分别具有光滑、粗糙和及粗糙外观形态。污染城市大气环境中生物质颗粒物多为菌类及生物残体。各类颗粒物常常粘附混杂在一起,当中有些是由丝状生物质颗粒物缠绕捕获而成。     

燃煤火电厂超低排放机组性能测试技术研究

燃煤火电厂超低排放机组性能测试是超低排放工程验收的重要环节,也是环保部门验收的依据。由于实施超低排放后,污染物浓度更低,增加了污染物测试难度,尤其是对颗粒物的测试。本论文主要基于理论研究与现场实测经验研究了超低排放机组颗粒物、二氧化硫等性能测试方法、测试原理以及主要仪器,对于超低排放机组性能测试具有重要意义。     

湿式电除尘器性能测试方法研究

湿式电除尘器是燃煤电厂烟尘超低排放的主流除尘技术之一。针对湿式电除尘器的测试特点,提出了测试工况、测孔位置、测孔尺寸及采样点布置等相关要求,并分别对颗粒物、PM_(2.5)、SO_3等开展测试研究,给出了科学的测试方法:针对颗粒物,基于烟道内、烟道外两种采样方法,过滤装置内可配置滤膜或滤筒,应开展空白试验,当浓度较低时应采用一体化采样头;针对PM_(2.5),建议采用重量法(撞击器法)作为基准方法;针对SO_3,可采用冷凝法进行采样,当浓度较低时,建议采用冷凝法与吸收法相结合的手段。并基于此开展了现场实测,为国标《湿式电除尘器性能测试方法》的研制提供了技术及数据支撑,满足了燃煤电厂烟气超低排放测试的迫切需求。     

新型干法水泥生产线PM_(2.5)超细颗粒物排放测试方法研究

近来,PM2.5因含大量有毒有害物质,对人体健康和大气环境质量产生很大影响而受到社会关注,其防治已成为我国"十二五"环境保护重点工作之一。我国水泥产量已占全球的60%,且今后几年可能还会增长。据统计,2009年我国水泥行业颗粒物排放量约占工业排放总量的30%。这些颗粒中有多少PM2.5目前还是个未知数。这些颗粒物的PM2.5该如何测试?哪种方法更好?将针对新型干法水泥厂烟气的特点来探讨合理的PM2.5测试方法。     

排水管道中雨污水颗粒物沉降速率特征分析

排水管道可接纳雨水径流和旱流污水,雨天形成雨污混合水,水流中部分颗粒沉降至管底形成沉积物。对比分析上述各环节中颗粒物的沉降速率特征,有助于提高对雨污混合水的管控效率。研究选取某合流管段,采集雨污混合水、雨水径流、管道沉积物及旱流污水,并采用淘析分离方法,开展颗粒物沉降速率(SV)特征分析,基于此建立颗粒物沉降速率与质量占比的拟合关系。结果显示,雨污混合水中颗粒物SV≥0.265 mm/s的比例与管道沉积物相近,且与雨水径流及旱流污水存在一定差异,说明在雨天水流运行过程中,部分管道沉积物被冲起,使雨污混合水中颗粒物SV得到显著提升。进一步分析显示,在每个SV下,降雨量越高,低于该SV的颗粒占比更少,且不易沉降的颗粒态污染物占比将会更高。该结果一方面说明,在较高雨量下SV较高的颗粒物更多被冲刷进入雨污混合水中;另一方面也说明,当雨天管网水量增加时,将会有更多不易沉降的颗粒态污染物进入管网下游,重力沉降设施的拦截效率将会显著下降。不同污染物的富集情况显示,PAHs、Cd、Cr和Pb在SV≥0.265 mm/s的颗粒物中占比较高,因此当设定SV=0.265 mm/s对雨污混合水进行重力沉降处理...     

基于多源观测资料的海峡西岸城市春季颗粒物污染研究

以海西区沿海城市为研究对象,重点分析了厦门地区2017年春季大气颗粒物污染过程中边界层要素演变及颗粒物水平和垂直分布特征,并利用地面观测数据、气溶胶激光雷达、卫星遥感分析等多源观测资料,探讨了3月1—2日颗粒物污染过程.研究表明,海西区颗粒物污染过程中,暖区条件下静稳小风和高温高湿条件有利于局地细颗粒物的吸湿增长,细颗粒物占比较高,而在受冷锋南下影响下东北大风和高湿条件下,粗颗粒占比较高;海西区沿海各城市的细颗粒污染趋势基本一致,而粗颗粒污染峰值在沿海城市由北向南依次出现,表现出显著的向南传输的特征;海西区细颗粒污染主要集中在近地面层,受人为源排放累积影响,粗颗粒则是由外源输入,并沉降至近地面附近;冷空气南下过程中,在由锋前暖区的静稳条件向冷锋过境转变时,气溶胶污染由局地累积向区域传输转变,颗粒物尺度也从细颗粒物转变为粗颗粒物.海西区空气总体较为清洁,在污染相对较小条件下,颗粒物污染是通过多来源、多尺度的污染物造成的,是受细颗粒局地源产生和输送及外源粗颗粒物的输入和沉降共同影响的.     

国Ⅳ天然气公交车实际道路颗粒物排放特性

采用车载排放测试系统对国Ⅳ天然气公交车进行了实际道路排放测试,研究其颗粒物排放特征及粒径分布随车速、加速度及比功率的变化规律.结果表明,天然气公交车的颗粒物数量和质量排放率随车速的增加均逐渐升高,而排放因子均逐渐减小;怠速、低速、中速和高速工况下颗粒数量浓度均呈多峰对数分布,核态颗粒数在总颗粒数中占大多数比例.随加速度的增大,颗粒物排放率逐渐升高;快加速工况颗粒物排放率明显高于匀速和慢减速工况,而后二者之间相差不大.颗粒物的高排放集中在高车辆比功率(VSP)区间内,并随VSP绝对值的增大逐渐升高.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.