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131.
Jian XU Yan HE Yuan ZHANG Changsheng GUO Lei LI Yuqiu WANG 《Frontiers of Environmental Science & Engineering》2013,7(6):836-843
The adsorption of sulfadiazine onto kaolinite clay as an alternative adsorbent was examined in aqueous solution, hnpacts of the contact time, pH, temperature, ionic strength and coexistent surfactants on the adsorption process were evaluated. The pH significantly influenced the adsorption process, with adsorption being promoted at lower pH due to the cation exchange mechanism. Decreasing ionic strength in the solution was favorable for adsorption, and the addition of cationic and anionic surfactants had negative effects on the adsorption capacity of sulfadiazine on kaolinite. Kinetic experiments showed that the adsorption followed the pseudo-second-order model. The equilibrium adsorption was well described by both Freundlich and Dubinin-Radushkevich (DR) models. According to the DR model, the adsorption mechanism was determined by cationic exchange and weak physical forces. The thermodynamic study showed that sulfadiazine adsorption onto kaolinite was a sponta- neous and endothermic reaction. 相似文献
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Kai LIU Fengkui DUAN Kebin HE Yongliang MA Yuan CHENG 《Frontiers of Environmental Science & Engineering》2014,8(2):284-292
Polycyclic aromatic hydrocarbons (PAHs) are complex organic compounds which are identified as significant carcinogenic to human health. PAHs (mainly in particle phase) are susceptible to atmospheric oxidant gases, especially ozone, nitrogen oxides (NOx), hydroxyl radical (OH), and could be degraded on filters during sampling process, leading to an underestimation of ambient PAH concentrations. The goal of this work was to investigate particle associated PAHs sampling artifacts caused by ozone in summer of Beijing. Comparative sampling systems were operated simultaneously during the whole campaign, one with activated carbon ozone denuder, the other being set as conventional sampling system. Activated carbon denuder was testified to be highly efficient to eliminate ozone from air stream. In general, nine particle-bound PAHs observed from conventional sampler were all lower than those from ozone denuder system. The total PAHs (particle phase) concentration was averagely underestimated by 35.9% in conventional sampling procedure. Benzo[a]pyrene (BaP) had the highest percentage of mass loss. founded to have influences Ambient temperature was on PAHs sampling artifacts. High temperature can increase loss of particle associated PAHs during sampling. 相似文献
134.
Ziyang LOU Xiaoli CHAI Youcai ZHAO Yu SONG Nanwen ZHU Jinping JIA 《Frontiers of Environmental Science & Engineering》2014,8(3):405-410
Variation and evolution process of leachate can be applied as a reference for landfill stabilization phase. In this work, leachates with different ages were collected from Laogang Refuse Landfill, and characterized with 14 key parameters. Simultaneously, principal component analysis (PCA) was applied to develop a synthetic parameter-F based on these 14 parameters, and a logarithm equation was simulated for the landfill stabilization process finally. It was predicted that leachates would meet Class I and Class II in standard for pollution control on the landfill site of municipal solid waste (GB 16889-1997) after 32 years and 22 years disposal under the natural attenuation in the humid and warm southern areas of China, respectively. The predication of landfill state would be more accurate and useful according to the synthetic parameter F of leachate from a working landfill. 相似文献
135.
通过比较实验,研究了在大肠菌群测定过程中菌龄、细菌密集程度、媒染时间、脱色程度等因素对革兰氏染色正确性的影响,从而得出了一最佳革兰氏染色条件组合,并提出了确保革兰氏染色技术操作正确的方法。 相似文献
136.
广西山地漂白黄壤分布在中、低山地的上部,即海拔1200m以上的山体坡面和山顶部位,成为广西土壤垂直带谱最上层结构的主要土壤类型.在温暖多雨、多云雾的亚热带季风气候条件下,以常绿阔叶林为主的自然森林植被生长茂密,土壤矿物分解较为彻底,成土过程主要是旺盛的生物富集过程、明显的脱硅富铅化与水化过程以及强烈的淋浴侧渗漂洗过程。土壤剖面层次发育明显,具A1-A2-E-B-C或AH-A-E-B-C构型。土壤质地多为重壤土至中粘土,呈强酸性反应。表土阳离子代换量中等,有机质含量丰富,肥力高,适于发展林业,特别是发展水源林和水土保持林,它是广西最重要的水源林区。 相似文献
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139.
煤燃烧过程中微量元素铬、铅的迁移转化规律研究 总被引:5,自引:1,他引:5
通过化学逐级提取法等手段,研究了煤中铬、铅在燃烧过程中的迁移转化规律及其环境稳定性,掌握了其在燃烧产物中的形态和分布,为开展燃煤电厂灰渣中重金属污染的防治工作提供了依据。 相似文献
140.
泥石流输沙对小江中下游河床演变的影响 总被引:4,自引:1,他引:4
对小江中下游近90km河床及两岸泥石流进行了调查研究。得到:泥石流输沙年际和季节变化大;泥石流高强度的输沙造成小江河床特殊的平面和剖面特征;泥石流堵塞小江河道,对纵比降有再造作用;泥沙使小江河床以年均20cm~50cm速度抬升。 相似文献