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991.
以自制沸石咪唑酯骨架材料ZIF-90为原料,自制2,3,4,5,6-五氟苄胺为修饰剂,通过后修饰法制备了超疏水ZIF-90,采用SEM、XRD、FTIR等技术对其进行了表征,并进行了气体吸附性能测试。表征结果显示:制备的超疏水ZIF-90晶体结构和形貌良好;水接触角高达152.1°;修饰剂分子与ZIF-90晶体上的自由醛基成功发生缩胺反应。气体吸附实验结果表明:当相对压力小于0.02时,超疏水ZIF-90的CO_2吸附量较ZIF-90明显增大,CO_2/N_2和CO_2/CH_4的理想吸附选择系数由修饰前的15.76和4.88分别提升至33.28和17.13;超疏水ZIF-90具有优异的憎水性能。 相似文献
992.
Loos R Gawlik BM Locoro G Rimaviciute E Contini S Bidoglio G 《Environmental pollution (Barking, Essex : 1987)》2009,157(2):561-568
This study provides the first EU-wide reconnaissance of the occurrence of polar organic persistent pollutants in European river waters. More than 100 individual water samples from over 100 European rivers from 27 European Countries were analysed for 35 selected compounds, comprising pharmaceuticals, pesticides, PFOS, PFOA, benzotriazoles, hormones, and endocrine disrupters. Around 40 laboratories participated in this sampling exercise. The most frequently and at the highest concentration levels detected compounds were benzotriazole, caffeine, carbamazepine, tolyltriazole, and nonylphenoxy acetic acid (NPE1C). Only about 10% of the river water samples analysed could be classified as “very clean” in terms of chemical pollution. The rivers responsible for the major aqueous emissions of PFOS and PFOA from the European Continent could be identified. For the target compounds chosen, we are proposing “indicative warning levels” in surface waters, which are (for most compounds) close to the 90th percentile of all water samples analysed. 相似文献
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995.
城市污水处理厂第二沉淀池出水的污染物浓度较低,经过矿化及灭菌等深度处理后可以回用,从而减轻对淡水资源的需求。本实验采用溶胶-凝胶法制备了负载TiO2的浮石光催化剂,对城市污水处理厂第二沉淀池出水进行了矿化及灭菌处理研究。采用低压汞灯对处理水样照射2h,有机物降解率可以达到50%,灭菌效率达到100%。处理后的水可以作为农作物灌溉、城市绿化和娱乐用水。负载在浮石表面的TiO2薄膜经过10次的光催化循环实验后,没有明显破损,可以再次循环使用。TiO2浮石具有质轻、机械性能好和价格低等优点,该方法处理废水的适用浓度低,可以广泛应用于微污染水和城市污水处理厂出水的深度处理。 相似文献
996.
通过恒温振荡平衡法研究了Pb~(2+)在针铁矿上的等温吸附和吸附动力学特征,探讨了吸附的影响因素.结果表明:(1)随Pb~(2+)平衡浓度和pH的增大,针铁矿对Pb~(2+)的吸附量逐渐增大.(2)针铁矿对Pb~(2+)的等温吸附可用Freundlich和Langmuir方程较好地拟合.(3)在相同温度和pH下,随离子强度的提高,针铁矿对Pb~(2+)的吸附量增大.(4)在相同离子强度和pH下,针铁矿对Pb~(2+)的吸附量总体随温度升高而增大.针铁矿对Pb~(2+)的吸附是自发进行的吸热反应.(5)针铁矿吸附Pb~(2+)的过程可分为初始的快吸附和随后的慢吸附2个阶段.pH影响吸附反应快慢,随pH增大吸附速率增大;随着pH的增大,达到平衡吸附的时间缩短.吸附动力学方程用Elovich方程拟合最佳. 相似文献
997.
Shelly L. Miller Peter Scaramella Joseph Campe Cynthia W. Goss Sandra Diaz-Castillo Ed Hendrikson Carolyn DiGuiseppi Jill Litt 《Atmospheric environment (Oxford, England : 1994)》2009,43(35):5661-5667
An indoor air quality assessment was conducted on 100 homes of recent Mexican immigrants in Commerce City, Colorado, an urban industrial community north of Denver. Head of households were administered a family health survey, filled out an activity diary, and participated in a home inspection. Carbon monoxide (CO) and carbon dioxide (CO2) were measured for 24 h inside the main living area and outside of the homes. Harvard Impactors were used to collect 24-h samples of PM2.5 at the same locations for gravimetric analysis. Dust samples were collected by vacuuming carpeting and flooring at four locations within the home and analyzed by ELISA for seven allergens. Mean indoor and outdoor PM2.5 levels were 27.2 and 8.5 μg m−3, respectively. Indoor PM2.5 and CO2 were elevated in homes for which the number of hours with door/window open was zero compared to homes in which the number of hours was high (>15 h). Indoor PM2.5 levels did not correlate with outdoor levels and tended to increase with number of inhabitants, and results indicate that the source of indoor particles were occupants and their activities, excluding smoking and cooking. Mean indoor CO2 and CO levels were 1170 and 2.4 ppm, respectively. Carbon monoxide was higher than the 24-h National Ambient Air Quality Standard in 3 of the homes. The predominant allergens were cat (Fel d 1) and mouse (Mus m 1) allergens, found in 20 and 34 homes, respectively. 相似文献
998.
Isabelle Batisson Olivier Crouzet Martine Sancelme Clarisse Mallet 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1195-1201
Dissipation kinetics of mesotrione, a new triketone herbicide, sprayed on soil from Limagne (Puy-de-Dôme, France) showed that the soil microflora were able to biotransform it.Bacteria from this soil were cultured in mineral salt solution supplemented with mesotrione as sole source of carbon for the isolation of mesotrione-degrading bacteria. The bacterial community structure of the enrichment cultures was analyzed by temporal temperature gradient gel electrophoresis (TTGE). The TTGE fingerprints revealed that mesotrione had an impact on bacterial community structure only at its highest concentrations and showed mesotrione-sensitive and mesotrione-adapted strains. Two adapted strains, identified as Bacillus sp. and Arthrobacter sp., were isolated by colony hybridization methods.Biodegradation assays showed that only the Bacillus sp. strain was able to completely and rapidly biotransform mesotrione. Among several metabolites formed, 2-amino-4-methylsulfonylbenzoic acid (AMBA) accumulated in the medium. Although sulcotrione has a chemical structure closely resembling that of mesotrione, the isolates were unable to degrade it. 相似文献
999.
Sachin D. Ghude R.J. Van der A S. Fadnavis 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1873-1878
We assessed satellite derived tropospheric NO2 distribution on a global scale and identified the major NO2 hotspot regions. Combined GOME and SCIAMACHY measurements for the period 1996-2006 have been used to compute the trends over these regions. Our analysis shows that tropospheric NO2 column amounts have increased over the newly and rapidly developing regions like China (11 ± 2.6%/year), south Asia (1.76 ± 1.1%/year), Middle East (2.3 ± 1%/year) and South Africa (2.4 ± 2.2%/year). Tropospheric NO2 column amounts show some decrease over the eastern US (−2 ± 1.5%/year) and Europe (0.9 ± 2.1%/year). We found that although tropospheric NO2 column amounts decreased over the major developed regions in the past decade, the present tropospheric NO2 column amounts over these regions are still significantly higher than those observed over newly and rapidly developing regions (except China). Tropospheric NO2 column amounts show some decrease over South America and Central Africa, which are major biomass burning regions in the Southern Hemisphere. 相似文献
1000.
双水相气浮浮选光度法处理环境水样中痕量土霉素残留物 总被引:1,自引:0,他引:1
建立了一种新型分离方法--双水相气浮浮选光度法,使其处理环境水样中痕量土霉紊(OTC)残留物,研究了其工作原理,并用高效液相色谱法对该方法的可靠性进行了验证.利用自制的双水相气浮浮选装置,选择四氢呋喃作亲水有机溶剂、质量分数为10%的NaCl溶液作分相剂,NaOH溶液调节pH,将Cu2+与OTC形成的疏水配合物浮选至有机相,实现OTC与水样分离.浮选完毕后,经紫外-可见分光光度法分析,线性回归方程为A=1.532×105c+0.1230(其中:A为有机相的吸光度;c为水样的OTC摩尔浓度,mol/L),相关系数为0.9998,该方法的线性范围为4.8×10-7~7.3×10-5 mol/L,OTC加标回收率为99.5%~100.1%. 相似文献