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281.
以某污水厂的氧化沟污泥和剩余污泥为培养对象,获得了SRB占优的厌氧污泥,分析了活性污泥厌氧驯化过程中微生物的分布规律,考察了不同种类SRB污泥固定化小球处理水中硫酸根、锌及镉的效果.结果表明:pH6.0～7.0,温度35℃,硫酸盐浓度4g/L,时间在24h时,剩余污泥固定化小球处理含Zn(II)400mg/L的废水,去除率达到100%,氧化沟污泥固定化小球Zn(II)的去除率为90%左右;对500mg/L含镉废水,剩余污泥固定化小球8h能去除水中95?(II),氧化沟污泥固定化小球对Cd(II)的去除率为80%.硫酸盐还原菌污泥固定化技术中剩余污泥优于氧化沟污泥. 相似文献
282.
Zhuobiao M Chengtang Liu Chenglong Zhang Pengfei Liu Can Ye Chaoyang Xue Di Zhao Jichen Sun Yiming Du Fahe Chai Yujing Mu 《环境科学学报(英文版)》2019,31(5):121-134
Air concentrations of volatile organic compounds (VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and 9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most (36.15%) to the total propene-equivalent concentration of the measured VOCs, followed by combustion emission (16.92%), vegetation emission and secondary formation (14.33%), solvent usage (10.59%), petrochemical industry emission (9.89%), petrol evaporation (6.28%), and liquefied petroleum gas (LPG) usage (5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics, e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O3 pollution in Shenyang. 相似文献
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Xionghui Qiu Lei Duan Jian Gao Shulan Wang Fahe Chai Jun Hu Jingqiao Zhang Yaru Yun 《环境科学学报(英文版)》2016,28(2):75-83
To elucidate the air pollution characteristics of northern China, airborne PM_10(atmospheric dynamic equivalent diameter ≤ 10 μm) and PM_(2.5)(atmospheric dynamic equivalent diameter ≤ 2.5 μm) were sampled in three different functional areas(Yuzhong County,Xigu District and Chengguan District) of Lanzhou, and their chemical composition(elements, ions, carbonaceous species) was analyzed. The results demonstrated that the highest seasonal mean concentrations of PM_10(369.48 μg/m~3) and PM_(2.5)(295.42 μg/m~3) were detected in Xigu District in the winter, the lowest concentration of PM_(2.5)(53.15 μg/m~3) was observed in Yuzhong District in the fall and PM_10(89.60 μg/m~3) in Xigu District in the fall.The overall average OC/EC(organic carbon/elemental carbon) value was close to the representative OC/EC ratio for coal consumption, implying that the pollution of Lanzhou could be attributed to the burning of coal. The content of SNA(the sum of sulfate, nitrate,ammonium, SNA) in PM_(2.5)in Yuzhong County was generally lower than that at other sites in all seasons. The content of SNA in PM_(2.5)and PM_10 in Yuzhong County was generally lower than that at other sites in all seasons(0.24–0.38), indicating that the conversion ratios from precursors to secondary aerosols in the low concentration area was slower than in the area with high and intense pollutants. Six primary particulate matter sources were chosen based on positive matrix factorization(PMF) analysis, and emissions from dust, secondary aerosols, and coal burning were identified to be the primary sources responsible for the particle pollution in Lanzhou. 相似文献
286.
研究了2,4二硝基氯苯在十二烷基磺酸钠/油/醇/水组成的O/W型微乳液中的水解反应.考察了烃、醇与表面活性剂的种类及用量、OH-浓度和温度等对O/W型微乳液中2,4二硝基氯苯水解反应的影响.结果表明,在微乳液介质中,水解反应为亲核取代的二级反应.在OH-大大过量的条件下,可视为准一级反应.烃的介电常数越小、醇的支链越多及正醇的碳原子数越少,水解反应的速率常数越大;烃的量较少、表面活性剂量较多及醇的量适中时,水解速率较快.温度升高,水解速率加快,水解反应的活化能为56.78kJ·mol-1. 相似文献
287.
Threat of heavy metal contamination in eight mangrove plants from the Futian mangrove forest,China 总被引：2，自引：0，他引：2
Mangrove plants play an important role in heavy metal maintenance in a mangrove ecosystem. To evaluate the characteristics of heavy metal contamination in the Futian mangrove forest, Shenzhen, China, eight heavy metals in mangrove sediments and plants were monitored, including essential elements such as Cu and Zn, and non-essential elements such as Cr, Ni, As, Cd, Pb and Hg. The results showed that the heavy metals exhibited the following scheme: Zn > As > Cu ≈ Cr > Pb > Ni > Cd ≈ Hg in sediment cores, among which Cd, As, Pb and Hg contents were nearly ten times higher than the background values. There was no significant difference in metal maintenance capability between native and exotic species. In mangrove plants’ leaves and stems, concentrations of Cu, Zn and As were higher than other heavy metals. The low bioconcentration factors for most heavy metals, except for Cr, implied the limited ability of heavy metal accumulation by the plants. Mangrove plants seem to develop some degree of tolerance to Cr. The factor analysis implies that anthropogenic influences have altered metal mobility and bioavailability. 相似文献
288.
考察了伯胺N1923对甲酸、乙酸、丙酸和丁酸以及氯乙酸、二氯乙酸和三氯乙酸等一元有机酸的萃取.萃取反应属离子缔合机理,有机相中主要生成1:1的萃合物探讨了有机酸种类、稀释剂性质、温度和无机盐等对萃取的影响、不同有机酸的萃取顺序为:三氯乙酸二氯乙酸丁酸氯乙酸丙酸乙酸、甲酸 低温、极性稀释剂和无机盐有利于萃取的进行,后两者对消除乳化现象(第三相)也起重要作用.同时用红外光谱对萃取机理进行了研究. 相似文献
289.
水生生物毒性测试广泛应用于评估化学品的水生态环境安全,而鱼类生态毒性数据为水生生态风险评估与风险管理提供基础。本文总结了现有的鱼类水生毒性测试标准及常用的物种。阐述了常用水生鱼类模式生物,如斑马鱼Danio rerio、青鳉鱼Oryzias latipes、黑头软口鲦Pimephales promelas等作为模式鱼类的特征及在生态毒性测试中的应用。环保部7号令推荐稀有鮈鲫Gobiocypris rarus作为中国本土生物在水生毒性测试中使用。目前公开发表的利用稀有鮈鲫的水生毒性研究多集中在急性毒性方面,对其他类型的研究如法规毒理相关的长期慢性毒性有待开展。 相似文献
290.