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101.
The study investigated the effects of ethanol on the adsorption properties of bentonite and kaolin for benzene and toluene removal. 相似文献
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采用超滤膜法将2-丁烯醛生产废水中的有机物分为相对分子质量不同的7个级分,并应用溶解性有机碳(dissolved organic carbon,DOC)、紫外吸收光谱(ultraviolet spectrum,UV)、傅里叶变换红外光谱(fourier transform infrared spectrometer,FT-IR)和气相色谱/质谱联用仪(gas chromatography with mass spectrometry,GC-MS)技术对不同相对分子质量区间的有机物所占比例及物质结构进行了研究.结果表明,废水中相对分子质量1×103的有机物所占比例最高,达到88.57%;采用GCMS对废水中相对分子质量1×103的级分进行分析,定性出27种化合物,包含醛、酮、酯、醇、酚、酸、烷烃类及其他苯系物等,其峰面积占有机物峰面积总和的比例分别为6.9%、5.3%、35.4%、13.2%、4.6%、0.4%、1.7%、16.8%,总和为84%.UV和FT-IR分析结果均显示不同相对分子质量区间的光谱吸收特征没有明显差别,级分中存在含有不饱和双键、羟基、羰基化合物及芳香族化合物,与GC-MS检测结果相吻合.研究结果为废水处理工艺的开发与优化提供了重要的指导作用. 相似文献
105.
利用δ15N-NO3-和δ18O-NO3-示踪北京城区河流硝酸盐来源 总被引:2,自引:2,他引:0
为定量化识别北京城区河流硝酸盐来源,采用δ~(15)N-NO~-_3和δ~(18)O-NO~-_3双同位素示踪法对北京城区河流河水硝酸盐的氮氧稳定同位素组成进行分析,利用稳定同位素混合模型追溯北京城区河流硝酸盐来源,并评估各污染源的贡献率.结果表明:1北京河流无机氮污染以硝酸盐氮(NO~-_3-N)污染为主,且河流下游硝酸盐氮污染较为严重.2北京城区地表河流δ~(15)N-NO~-_3值范围为6.26‰~24.94‰,δ~(18)O-NO~-_3值范围为-0.41‰~11.74‰;下游δ~(15)N-NO~-_3值比上游大.3根据稳定同位素混合模型,北京河流中硝酸盐贡献率平均值分别为:粪肥及生活污水61.2%、土壤有机氮31.5%、大气沉降7.3%. 相似文献
106.
聚β羟基烷酸盐(PHA)以其较好的生物相容性、可生物降解性和再生性成为最有前途的生物高分子材料.本文基于甘油作为基质在饱食-饥饿模式下富集合成PHA的混培物,以乙酸、丙酸、丁酸、乳酸和葡萄糖作为基质考察混培物合成PHA的基质广谱性,结果表明乳酸和乙酸作为基质时PHA的产率系数较高;使用不同比例乙酸/丙酸混合基质时,PHA产量随着乙酸含量的增加而增大,乙酸/丙酸为3∶1时PHA产量最高.通过活性污泥同时贮存与生长模型模拟与线性回归两种方法证实,在单一基质或乙酸/丙酸混合基质情况下,PHA合成速率与OUR存在线性关系,因此,基于在线OUR测量数据可以实时估计PHA合成量. 相似文献
107.
Qiushi Shen Qilin Zhou Jingge Shang Shiguang Shao Lei Zhang Chengxin Fan 《环境科学学报(英文版)》2014,26(2):281-288
Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column. 相似文献
108.
Hong Zhao Yunshan Ge Tiezhu Zhang Jipeng Zhang Jianwei Tan Hongxin Zhang 《环境科学学报(英文版)》2014,26(10):2027-2033
The alteration and formation of toxic compounds and potential changes in the toxicity of emissions when using after-treatment technologies have gained wide attention. Volatile organic compound(VOC), carbonyl compound and particle-phase polycyclic aromatic hydrocarbon(PAH) emissions were tested at European Steady State Cycle(ESC) to study unregulated emissions from a diesel engine with a fuel-borne catalyst and diesel particulate filter(FBC–DPF). An Fe-based fuel-borne catalyst was used for this study. According to the results, brake specific emissions of total VOCs without and with DPF were 4.7 and4.9 mg/kWh, respectively, showing a 4.3% increase. Benzene and n-undecane emissions increased and toluene emission decreased, while other individual VOC emissions basically had no change. When retrofitted with the FBC–DPF, total carbonyl compound emission decreased 15.7%, from 25.8 to 21.8 mg/kWh. The two highest carbonyls, formaldehyde and acetaldehyde, were reduced from 20.0 and 3.7 to 16.5 and 3.3 mg/kWh respectively. The specific reactivity(SR) with DPF was reduced from 6.68 to 6.64 mg/kWh. Total particle-phase PAH emissions decreased 66.4% with DPF compared to that without DPF. However, the Benzo[a]pyrene equivalent(BaPeq) with DPF had increased from 0.016 to 0.030 mg/kWh.Fluoranthene and Pyrene had the greatest decrease, 91.1% and 88.4% respectively. The increase of two- and three-ring PAHs with DPF indicates that the fuel-borne catalyst caused some gas-phase PAHs to adsorb on particles. The results of this study expand the knowledge of the effects of using a particulate filter and a Fe-based fuel-borne catalyst on diesel engine unregulated emissions. 相似文献
109.
Carbonyl emissions from heavy-duty diesel vehicle exhaust in China and the contribution to ozone formation potential 总被引:6,自引:0,他引:6
Fifteen heavy-duty diesel vehicles were tested on chassis dynamometer by using typical heavy duty driving cycle and fuel economy cycle. The air from the exhaust was sampled by 2,4- dinitrophenyhydrazine cartridge and 23 carbonyl compounds were analyzed by high performance liquid chromatography. The average emission factor of carbonyls was 97.2 mg/km, higher than that of light-duty diesel vehicles and gasoline-powered vehicles. Formaldehyde, acetaldehyde, acetone and propionaidehyde were the species with the highest emission factors. Main influencing factors for carbonyl emissions were vehicle type, average speed and regulated emission standard, and the impact of vehicle loading was not evident in this study. National emission of carbonyls from diesel vehicles exhaust was calculated for China, 2011, based on both vehicle miles traveled and fuel consumption. Carbonyl emission of diesel vehicle was estimated to be 45.8 Gg, and was comparable to gasolinepowered vehicles (58.4 Gg). The emissions of formaldehyde, acetaldehyde and acetone were 12.6, 6.9, 3.8 Gg, respectively. The ozone formation potential of carbonyls from diesel vehicles exhaust was 537 mg O3/km, higher than 497 mg O3/km of none-methane hydrocarbons emitted from diesel vehicles. 相似文献
110.
陈荣 《资源节约和综合利用》2014,(9):58-58
你想象过以后开车,只需要加水就能跑吗?水是地球上最为丰富的化合物,一直以来,人类从未停止过探索水燃料的脚步。今天要介绍的,就是那些从水中提取能源的神奇科技。 相似文献