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排序方式: 共有1419条查询结果,搜索用时 15 毫秒
911.
用陶瓷膜做滤材处理含油废水的研究   总被引:6,自引:0,他引:6  
本实验是以无机膜之一的陶瓷做滤材,对含油污水处理进行研究.探讨了含油种类与膜的性质、含油浓度和透过速度的关系及反冲洗对透过速度的影响.通过实验证明:轻质油比重油的透过速度大;油水中含油浓度对透过浓度影响不大;反冲洗会使透过速度得到恢复;浊度去除率可达96%以上,陶瓷膜超滤法处理含油废水是可行的.  相似文献   
912.
上海人口郊区化与城市可持续发展   总被引:9,自引:0,他引:9  
人口郊区化是大城市发展的必然趋势。本文分析了上海人口郊区化的特征及其动因 ,并阐述了人口郊区化对上海人口与经济、社会、环境的相互协调和实现可持续发展的作用。  相似文献   
913.
利用热解及钙盐沉淀法对农药含钾废渣进行处理,制得高纯度的KCl.通过管式炉反应器对农药含钾废渣中有机物的去除进行了研究,探讨了升温速率、热解终温、终温保持时间及空气流量对热解过程的影响,并对钙盐沉淀法除氟过程的溶液pH及m(Ca2+)∶m(F-)进行了确定.实验结果表明:当升温速率为20℃/min、热解终温为600℃、终温保持时间为90 min、空气流量为3.0m3/min时,废渣中的有机物完全分解;钙盐沉淀法除氟的最佳条件为溶液pH 8,m(Ca2+)∶m(F-)=3.0,氟离子的去除率达到98%;最终得到KCl的产率为70.6%,产品纯度为98.2%,符合国家Ⅰ级优等品标准.  相似文献   
914.
太阳光催化降解阿特拉津的研究   总被引:2,自引:0,他引:2  
利用太阳光作光源,用含在颗粒活性炭中的TiO2(TiO2/GAC)作光催化剂,在流动循环系统中考察了阿特拉津的光催化降解效果。在阿特拉津初始质量浓度27.18mg/L、液体循环流量6L/h、液体总体积400mL、平均辐照度2.64mW/cm^2、液体温度40℃、TiO2/GAC质量浓度7g/L、3%H2o2用量240μL,光催化反应时间1.65h的条件下,阿特拉津去除率达92.8%,TOC去除率接近70%。通过测定光催化降解过程中TOC的变化、紫外吸收光谱吸收峰的变化和质谱图对阿特拉津的降解途径和降解程度进行了分析。  相似文献   
915.
916.
Remote sensing offers many advantages in the development of ecosystem indicators for the pelagic zone of the ocean. Particularly suitable in this context are the indicators arising from time series that can be constructed from remotely sensed data. For example, using ocean-colour radiometry, the phenology of phytoplankton blooms can be assessed. Metrics defined in this way show promise as informative indicators for the entire pelagic ecosystem. A simple phytoplankton–substrate model, with forcing dependent on latitude and day number is used to explore the qualitative features of bloom phenology for comparison with the results observed in a suite of 10-year time series of chlorophyll concentration, as assessed by remote sensing, from the Northwest Atlantic Ocean. The model reveals features of the dynamics that might otherwise have been overlooked in evaluation of the observational data.  相似文献   
917.
杨雪梅  金杉  于杭仟 《安全》2010,31(12):18-20,24
通过了解燃气空调的分类、工作原理及其火灾危险性,分析地下室设置燃气空调机组的可能性,提出其消防安全措施。  相似文献   
918.
ABSTRACT

The degradation dynamics and terminal residues of dufulin enantiomers were investigated in two typical corn plants. A convenient and precise chiral method by high-performance liquid chromatography coupled with tandem triple quadrupole mass spectrometry (HPLC/MS/MS) using a Chiralpak IC column was developed and validated for measuring dufulin enantiomers in corn plants and corn. The two enantiomers of dufulin quickly dissipated in the corn plant, and no noticeable stereoselectivity was observed during degradation or in the final residues. After 30% rac-dufulin wettable powder with a 1- to 1.5-fold dose of the recommended value was sprayed two to three times on corn plants, the residue levels of S-(+)-dufulin and R-(-)-dufulin in corn from both sites were lower than or equal to 0.0520 mg kg–1 on days 7, 14 and 21 after the last application. The dietary risk assessment indicated that dufulin did not exhibit obvious dietary health risks in corn samples when good agricultural practices were implemented. The findings from this study may be used to better understand the chiral profiles of dufulin in the environment and the effect of dufulin residues in corn on health.  相似文献   
919.
Li W  Zhang S  Jiang W  Shan XQ 《Chemosphere》2006,63(8):1235-1241
Interactions between anions and cations are important to understand the chemical processes of pollutants in environment. In this study, batch experiments were carried out to investigate the simultaneous adsorption of Cu and Cd on hematite as affected by phosphate. Phosphate pretreatment suppressed the maximum adsorption of Cu and Cd on hematite and moved the adsorption pH edges to a higher pH range. Phosphate application time had a marked impact on Cu and Cd adsorption and longer contact time resulted in more reduction of Cu and Cd adsorption. Results of back-titration, Fourier transform infrared (FTIR) spectroscopy study and ionic strength effect on the adsorption revealed that Cu and Cd were adsorbed on hematite mainly through the inner-sphere complex formation mechanism and phosphate treatment reduced the inner-sphere adsorption sites, thus decreasing Cu and Cd adsorption on hematite.  相似文献   
920.
Mechanisms of competitive adsorption of Pb, Cu, and Cd on peat   总被引:15,自引:0,他引:15  
Combined use of batch equilibration adsorption and X-ray absorption spectroscopy (XAS) was employed to study the mechanisms of competitive adsorption of Pb, Cu, and Cd on Danish and Heilongjiang peat in single- and multi-solute systems. The adsorption capacity and initial adsorption rate on the same peat in single-solute systems followed the order Pb>Cu>Cd. Both the adsorbed amount of each metal (q'm) and its initial adsorption rate were decreased in multi-solute systems. It was observed that the adsorbed amounts of metals at low-energy adsorption sites (qm,1) decreased pronouncedly compared to those at high-energy adsorption sites (qm,2), indicating that the competitive adsorption of Pb, Cu and Cd occurred mainly at the low-energy adsorption sites. XAS study revealed that both Pb and Cu were coordinated in peat predominantly to carboxylic moieties without excluding the hydroxyl groups, thereby providing an insight into the mechanism of competitive adsorption of Pb and Cu on peat.  相似文献   
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