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氧化、还原改性对活性炭吸附草甘膦的影响 总被引:1,自引:0,他引:1
研究了氧化、还原改性对活性炭吸附草甘膦的影响.以傅立叶红外光谱定性表面官能团变化,以扫描电镜观察表面形貌,以化学吸附分析仪测定后再通过测定样品的氮气吸附/脱附等温线计算比表面积和孔径.结果表明:(1)氧化改性使活性炭比表面积增大;还原改性使活性炭比表面积减小.还原阶段使先前氧化阶段中产生的孔道以及原有孔道均发生塌陷,导致还原改性活性炭比表面积减小.(2)在静态吸附的条件下,氧化改性和还原改性活性炭对草甘膦的吸附均为吸热反应.还原改性在活性炭表面产生的还原性官能团有利于活性炭对草甘膦的吸附,而氧化改性产生的氧化性官能团并不利于活性炭对草甘膦的吸附.(3)热力学参数的计算进一步表明,改性活性炭对草甘膦的吸附为吸热反应. 相似文献
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五氯苯酚在厌氧颗粒污泥中的吸附研究 总被引:2,自引:1,他引:1
在血清瓶中进行的分批实验中,研究了UASB和EGSB反应器厌氧颗粒污泥对五氯苯酚(PCP)的吸附、解吸规律.结果表明,吸附和解吸在接触PCP 2.5 h内达到平衡,吸附和解吸过程都符合Freundich等温方程,PCP的吸附机制为恒定的分配吸附.来自UASB反应器中活的颗粒污泥吸附能力大于灭活的颗粒污泥,Freundich等温方程吸附常数K值分别为0.557 0和0.037 9.UASB反应器颗粒污泥对PCP的吸附能力大于EGSB反应器颗粒污泥,Freundich等温方程吸附常数K值分别为0.557和0.263. 相似文献
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以光催化降解苯酚为探针反应,通过正交实验,系统研究了胶液配比、涂覆次数和焙烧温度等条件对以溶胶-凝胶法分别在普通钠钙玻璃和磨砂玻璃上制备TiO2光催化性能的影响,并利用环境扫描电镜(ESEM)对TiO2催化膜形貌进行了分析。研究表明,在普通钠钙玻璃片上负载TiO2催化膜的影响因素主次顺序为:硝酸体积〉涂覆次数〉焙烧温度〉V乙醇∶V酞酸丁酯,在选定实验条件下的最优条件为:涂覆次数为4次;焙烧温度=450℃;V乙醇∶V酞酸丁酯∶V硝酸(1∶4):V水=400∶40∶1∶4。在磨砂玻璃片上负载TiO2催化膜的的影响因素主次顺序为:涂覆次数〉硝酸体积〉焙烧温度〉V乙醇:V酞酸丁酯,在选定实验条件下的最优条件为:涂覆次数为4次;焙烧温度=500℃;V乙醇∶V酞酸丁酯∶V硝酸(1∶4)∶V水=400∶40∶2∶4。通过扫描电镜可以观察到在普通钠钙玻璃片和磨砂玻璃片表面均附着一层白色的TiO2薄膜,颗粒粒径在100 nm左右。磨砂玻璃比普通钠钙玻璃负载更多的催化剂,磨砂玻璃基TiO2活性更高。磨砂玻璃是一种非常有前景的TiO2催化剂载体材料。 相似文献
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Study on the cytotoxicity of microcystin-LR on cultured cells 总被引:7,自引:0,他引:7
The toxicity of purified blue-green algal toxin, microcystin-LR, on permanent cell lines KB, NIH/3T3, H-4-II-E, HeLa, Vero, Hep G2, Caco-2 and HL-60 was studied. Assessment of cell viability using colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays indicated that purified microcystin-LR induced toxic effect on KB and H-4-II-E cell lines after 96 h incubation at toxin concentrations greater than 18.75 microg/ml. KB cell line was selected for further study when reproducibility, consistency and sensitivity were considered. Significant amounts of lactate dehydrogenase (LDH) were released from KB cells when incubation durations were 72 and 96 h with toxin concentrations of 18.75 microg/ml and higher. Although previous studies suggested that microcystin-LR had no cytotoxic effect on permanent cell lines, LDH release assay performed on KB cells indicated that exposure to microcystin-LR could result in damage to the cell membrane. 相似文献
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研究了pH、初始浓度、时间及温度对甲基红在壳聚糖上吸附富集的影响。结果表明,pH是影响甲基红吸附富集的重要因素,最佳pH3.4。其动力学行为更好地符合Lagergren准二级反应动力学模型,随着温度增加,平衡吸附量减少。吸附过程的表观活化能(Ea)为7.518kJ/mol。壳聚糖对甲基红的吸附过程较好地符合Freundlich吸附等温方程。计算得到吸附过程的热力学参数△G0、△H0。和△S0分别为-24.88kJ/mol(303K)、-22.15kJ/mol和8.783J/(mol·K),表明壳聚糖对甲基红的吸附是一个自发的放热过程。红外光谱分析得到,壳聚糖吸附甲基红的过程中,壳聚糖分子中存在的大量羟基和氨基发挥了主要作用。 相似文献
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Three databases on air pollution effects on vegetation were developed by storing bibliographic and abstract data for technical literature on the subject in a free-form database program, 'askSam'. Approximately 4 000 journal articles have been computerized in three separate database files: BIOLEFF, LICHENS and METALS. BIOLEFF includes over 2 800 articles on the effects of approximately 25 gaseous and particulate pollutants on over 2 000 species of vascular plants. LICHENS includes almost 400 papers on the effects of gaseous and heavy metal pollutants on over 735 species of lichens and mosses. METALS includes over 465 papers on the effects of heavy metals on over 830 species of vascular plants. The combined databases include articles from about 375 different journals spanning 1905 to the present. Picea abies and Phaseolus vulgaris are the most studied vascular plants in BIOLEFF, while Hypogymnia physodes is the most studied lichen species in LICHENS. Ozone and sulfur dioxide are the most studied gaseous pollutants with about two thirds of the records in BIOLEFF. The combined size of the databases is now about 5.5 megabytes. 相似文献
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CaCl2浓度对土壤吸附西维因的影响研究 总被引:1,自引:0,他引:1
以北京交通大学校园草坪种植土为研究对象,研究了CaCl2浓度对西维因在土壤上吸附行为的影响,比较分析了不同CaCl2浓度下土壤对西维因的吸附动力学曲线和吸附等温线。实验结果表明,Elovich方程可以较好地拟合土壤对西维因的吸附动力学曲线。随着CaCl2浓度的增大,从快吸附到慢吸附过程所需要的吸附时间增加。西维因在土壤中的吸附等温线呈非线性特征,Freundlich和Langmuir吸附等温式均能较好地拟合吸附等温线。随着离子强度的增大,土壤对西维因的吸附容量降低。西维因浓度较低时,吸附等温线的线性要优于高浓度时的吸附等温线,进一步证明西维因在土壤上的吸附遵从"两相"吸附模式。 相似文献
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The effect of simulated rain on folpet and mancozeb residues on grapes and on vine leaves 总被引:1,自引:0,他引:1
Cabras P Angioni A Garau VL Melis M Pirisi FM Cabitza F Pala M 《Journal of environmental science and health. Part. B》2001,36(5):609-618
Artificial rainfalls were used to determine the effect of the amount of the rainfall and the time interval between pesticide application and rainfall event, on folpet and mancozeb residues on grapes and vine leaves. Forty-five mm of rain were administered to the vineyard in different amounts (45; 30+15; 15+15+15 mm). Folpet showed good rainfastness on the grapes and on the leaves. A modest decrease was observed only in the experiments that had received 45 mm of rain at one go. Mancozeb showed a lower rainfastness, since a portion of the deposit was easily washed off also by a modest rainfall. The percentage of this portion was higher in the grapes (38%) than in the leaves (20%). The data obtained in these experiments show that, in the case of folpet, it is not necessary to repeat the treatment when it rains the day after, while it is recommendable to repeat it in the case of mancozeb. 相似文献
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R H Young 《Journal - Water Pollution Control Federation》1972,44(6):1208-1211
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分析了目前各地实施的以经济开发区带动发展战略中的环境保护存在的问题,探讨进一步完善、强化和实施的若干对策。 相似文献
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The sorption behaviors of nitrobenzene on marine sediments were systematically investigated in this study. The nitrobenzene sorption on both HCl-treated and untreated sediments accorded well with the linear sorption isotherm. It occurred primarily through partition function of organic carbon of sediments. In comparison, the sorption behavior of nitrobenzene on H2O2-treated sediments was nonlinear and conformed to Langmuir isotherm. Sorption of nitrobenzene on H2O2-treated sediment was mainly through surface function of sediment minerals such as clays. With the increase of ionic strength (salinity), solubility of nitrobenzene in solution would decrease. At the same time, the release of dissolvable part of organic carbon into water solution would also decrease. As a result, partition coefficient and saturate adsorption amount of nitrobenzene on marine sediments increased with increasing salinity of seawater. Contrary to the influence of salinity, partition coefficient and saturate adsorption amount of nitrobenzene decreased with increasing temperature. 相似文献
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聚丙烯酰胺对活性污泥特性的影响研究 总被引:1,自引:0,他引:1
高分子混凝剂PAM投加是强化污泥造粒的有效方法,但PAM的投加对活性污泥中微生物群落以及对其生化降解性能的影响尚缺乏系统性研究。为此,通过实验室小型实验,在SBR中连续投加PAM,运用FISH等微生物检测技术,研究了PAM对活性污泥的影响。在PAM投量为3 mg/L的条件下,反应器中活性污泥的生长过程与对照反应器没有根本性差别,且PAM投加后MLSS浓度和单位重量污泥的生物量均有一定增大,污泥的沉降性能也得到改善。FISH检测的结果表明,与对照反应器相比,总细菌、亚硝化菌、硝化菌的个数分别由9.1×105、1.8×105和1.1×105CFU/mL增长到1.0×106、2.0×105和1.2×105CFU/mL,说明PAM没有对各种菌落的生长产生不利影响。连续运行80 d的结果也表明,投加PAM的反应器中COD和氨氮的去除均有所改善。 相似文献