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941.
942.
943.
The use of high resolution (10,000 resolving power) coupled gas chromatography - mass spectrometry is a well established technique in the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) but in the case of heavily contaminated stack samples interferences can still occur. A complementary technique that offers high specificity is selected reaction monitoring (SRM).A study has been made into the effects that affect the metastable dissociation of 2,3,7,8-TCDD in the first field free region (FFR1) of a magnetic sector mass spectrometer, and monitored using SRM.Monatomic, diatomic and polyatomic gases have been investigated in the collision chamber of the mass spectrometer, as have the effects of electron energy, source temperature and trap current on the dissociation, and optima conditions determined for them. 相似文献
944.
本文用0.3mBenton-34/OV-1短填充柱气相色谱法研究了萘在焚烧炉飞灰上的氯化反直产物,实验表明,飞灰表面性质对氯化有促进作用,这种促进作用与飞灰的来源或表面性质有强烈关系,文中对有关分析方法和萘在焚烧炉飞灰上氯化反应的结果作了讨论。 相似文献
945.
研究了TiO2与SO2,C7H16复相光化学反应的光催化活性.在SO2-C7H16-TiO2光催化反应过程中,TiO2表面可形成SO4^2-/TiO2结构,它的存在可提高庚烷的光催化氧化速率,利用IR和XPS研究了反应过程中TiO2表面形成的SO4^2-/TiO2结构。 相似文献
946.
对采油废水进行混凝预处理后进行了Fenton处理 ,确定了Fenton试剂处理采油废水的最佳配比为H2 O2 ∶Fe2 +=5 0mmol L :1mmol L。同时利用GC MS色谱图探讨了混凝 -Fenton法对有机物的去除机理。结果表明 :混凝工艺去除了75 %的有机污染物 ,碳数低于 2 1的烷烃去除率可达到 80 %以上 ,同时还去除了所有的多环芳烃 ,但是对苯酚类物质的去除率只有 5 0 %。在Fenton过程中 ,铁的水解吸附和OH·的氧化作用并存 ,采油污水经过 12 0min的Fenton处理后 ,其中的烷烃类物质、酚类物质、多环芳烃物质能被完全氧化。 相似文献
947.
This study was conducted to biologically treat wastewater discharged from the textile industry (textiles made of cotton and/or synthetic fiber) using sequencing batch reactor (SBR) technology (activated sludge process operating on batch mode). To achieve the objectives of the study, the characteristics of textile wastewater and the biodegradation of its organic constituents under unsteady state conditions were studied. Then, a bench-scale pilot plant was used to study the performance of SBR by monitoring the settleability and change in the constituents (chemical oxygen demand and solids) over time. Results of the study showed that textile wastewater has different types of pollutants: heat, basicity, suspended solids, organic and inorganic matter, and heavy metals. The factors affecting the biodegradation of organic matter were determined as the reaction time and the ratio of initial substrate to sludge concentrations. Also, removal of solids was monitored, and the settling velocity as affected by sludge concentration was graphically presented to enable the determination of settling time. Finally, the outcome of this study was used to suggest a procedure for the design of a full-scale SBR unit for treatment of textile wastewater. 相似文献
948.
The effects of physicochemical conditions, such as pH, water hardness, flow rates and natural organic substances on the sensitivity of Ceriodaphnia dubia to the toxic effects of copper were investigated using static bioassay cups and specially designed flow-through bioassay chambers. We found that C.dubia was very sensitive to pH changes and the total copper LC50 values of C. dubia neonates increased by 15-fold as the pH increased from pH 7 to 10. It was also observed that the LC50 values increased sharply upon increasing the water hardness value to 2.4 meq. In addition, increasing flow rates from zeroto 50 mL hr-1 also increased its sensitivity to copper, which was possibly due to hydrodynamic stress.The presence of natural organic substances (humic acid and dissolved organic matter) and suspended particles decreased thetoxic effect of copper. This significant decrease in the toxicity of copper in the presence of natural organic materialscan be explained by a reduction in the free ion concentration due to complexation. Furthermore, we observed that the kinetics of copper interactions with natural organic materials are a significant factor in the toxic effect of copper and that the acute LC50 values increased with increasing reaction time betweensolubilized copper and water-borne organics. 相似文献
949.
为研究双酚A(BPA)在河口水中的光解动力学及水中重要溶解性组分对其光解的影响,在广西钦州大榄江连接茅尾海的河口水域采取水样,通过模拟日光实验研究了河口水中BPA的光解动力学,及河口水中的重要溶解性组分Cl-,Br-,溶解性有机质(DOM),NO3-和HCO3-对BPA光解的影响.结果表明,河口水中BPA的光解速率常数k值比纯水中大,且上游水样中BPA的k值是下游水样的2.5倍.稳态光解实验表明DOM及其与卤素离子作用显著影响BPA的光解,虽然NO3-也影响BPA光解,但与DOM共存时,NO3-的影响不明显.自由基淬灭和竞争反应动力学实验发现激发三重态DOM(3DOM*)和卤素自由基(HRS)是决定河口水样中BPA光降解的主要活性物种,且3DOM*与BPA的反应活性(二级反应速率常数k3DOM*,BPA=4.42×108L/(mol·s)要高于HRS与BPA的反应活性(kBPA,Cl·=2.11×108L/(mol·s),kBPA,Cl2·-=8.5×106L/(mol·s).下游水样中高含量的卤素离子(292mmol/L)易淬灭3DOM*产生反应活性较低的HRS,致使下游水体中BPA的光解速率低于上游水体. 相似文献
950.
运用事件研究法和非参数检验,探究了中央环保督察“回头看”的宣布实施对于沪深两市A股重污染行业上市公司收益情况的影响及其差异情况,结果显示:事件窗内中央环保督察“回头看”使得重污染行业上市公司的平均累计异常收益率降低至-2.005%,且这一负面冲击在时间上有延长趋势;不同公司性质、子行业的重污染行业上市公司所受影响存在显著差异.就企业性质差异而言,非国有公司累计收益率所受的负面冲击平均比国有公司高1.696%.在不同行业中,建材、制药、石化行业所受负面冲击最大,纺织、造纸、制革行业所受影响则较小.此外,市场对于火电、化工行业企业的反应并非多为负向,注重环境管理使得部分企业在中央环保督察“回头看”中得到了市场的正向回馈.建议持续推进中央环保督察“回头看”制度,以切实促进公司开展节能减排,同时,重污染行业公司特别是非国有公司以及上述行业公司应加强自身环境管理,积极进行环境信息披露,从而尽可能避免在类似的环境规制中受到负面冲击. 相似文献