Simple and efficient ion imprinted polymer for recovery of uranium from environmental samples

Ion imprinted polymer material (IIP) was prepared by forming ternary complexes of uranyl imprint ion with 1-(prop-2-en-1-yl)-4-(pyridin-2-ylmethyl)piperazine and methacrylic acid followed by thermal copolymerization with ethylene glycol dimethacrylate as the cross-linking monomer in the presence of 1,1'-azobis(cyclohexanecarbonitrile) initiator and 2-methoxy ethanol porogenic solvent. HCl solution (5 mol/L) was used to leach out the uranyl template ion from the IIP particles. Similarly, the control polymer (CP) material was also prepared exactly under the same conditions as the IIP but without the uranyl ion template. Various parameters such as solution pH, initial concentration, aqueous phase volume, sorbent dosage, contact time and leaching solution volumes were investigated. SEM, IR and BET-surface area and pore size analysis were used for the characterization of IIP and CP materials. The extraction efficiency of the IIP and CP was compared using a batch and SPE mode of extraction. The optimal pH for quantitative removal is 4.0-8.0, sorbent amount is 20 mg, contact time is 20 min and the retention capacity is 120 mg of uranyl ion per g of IIP. The IIP prepared demonstrated superior selectivity towards coexisting cations and therefore it can be used for selective removal of uranium from complex matrices.     

Critical modeling parameters identified for 3D CFD modeling of rectangular final settling tanks for New York City wastewater treatment plants

New York City Environmental Protection is in the process of incorporating biological nitrogen removal (BNR) in its wastewater treatment plants (WWTPs) which entails operating the aeration tanks with higher levels of mixed liquor suspended solids (MLSS) than a conventional activated sludge process. The objective of this paper is to discuss two of the important parameters introduced in the 3D CFD model that has been developed by the City College of New York (CCNY) group: (a) the development of the 'discrete particle' measurement technique to carry out the fractionation of the solids in the final settling tank (FST) which has critical implications in the prediction of the effluent quality; and (b) the modification of the floc aggregation (K(A)) and floc break-up (K(B)) coefficients that are found in Parker's flocculation equation (Parker et al. 1970, 1971) used in the CFD model. The dependence of these parameters on the predictions of the CFD model will be illustrated with simulation results on one of the FSTs at the 26th Ward WWTP in Brooklyn, NY.     

Electro-oxidation of two reactive azo dyes on boron-doped diamond electrode

Electrochemical oxidation (decolorization/degradation) of blue and red commercial reactive azo dyes was carried out on boron-doped diamond (BDD) electrode. The effect of various quantities of FeSO(4) was investigated in the electro-Fenton reaction on BDD. Progress of dyes degradation during the electrolysis and electro-Fenton reaction was monitored by UV-visible absorption and by estimation of the chemical oxygen demand (COD). Direct electrolysis showed a limiting capacity for red and blue dye removal even at high current densities, e.g. maximum red color and COD removal were 70 and 20%, respectively at 30 mA cm(-2) after 300 min. Higher red and blue color removal efficiencies were achieved by electro-Fenton oxidation. Current density of 30 mA cm(-2) in the presence of 0.05 mmol/L of FeSO(4) resulted in the red color and COD removal of 98 and 96%, respectively. The optimum FeSO(4) concentration for the electro-Fenton reaction was determined to be 0.05 mmol/L. Instantaneous current efficiency (ICE) in the presence of FeSO(4) was almost three times higher than for experiments carried out without FeSO(4).     

A pilot survey of 39 Victorian WWTP effluents using a high speed luminescent umu test in conjunction with a novel GC-MS-database technique for automatic identification of micropollutants

In 2007, samples of treated effluent were collected at point of discharge to the environment from 39 wastewater treatment plants (WWTPs) located across Victoria, Australia grouped by treatment type. Sample genotoxicity was assessed with a high-throughput luminescent umu test method using Salmonella typhimurium TL210 strain, with and without addition of a commercially available metabolic activation system. Samples were also screened using a gas chromatographic-mass spectrometric mass-structure database recognition method. A genotoxic response was observed in half of the samples tested without metabolic activation system (相似文献   

Characteristics of moisture and salinity of soil in Taklimakan Desert, China

The Taklimakan desert is known as the largest dunefield in China and also as the world's second largest shifting sand desert. The Tarim Desert Highway, which is the first highway to cross the Taklimakan desert, was built for the purpose of oil and gas resources extraction in the Tarim area, as well as for the development of the southern area of the Xinjiang Uygur Autonomous Region. Shelterbelts have been planted along the highway to prevent shifting sand from burying the road. This paper analyzes the variations of moisture and salinity of the unirrigated desert soil under natural conditions in the center of Taklimakan Desert. A number of important findings indicating the moisture and salinity of the soil at capillary saturation zone were determined by the groundwater and related to the evaporation on the top. Salinity could be affected by vegetation, which was different from moisture in the soil. Meanwhile, clay layer played an important role in water preservation in the soil, which was also beneficial to the accumulation of salinity in soil. Compared with clay layer, vegetation was a decisive factor for the gathering of salinity. The findings were significant for reasonable adjustment of irrigation in the shelterbelts for the further development of the Tarim Desert Highway.     

Masjed—Soleyman堆石坝在强震中的三维反应

177m高的Masjed—Soleyman分区堆石坝于2000年竣工，修建在伊朗西南部的高地震区。蓄水后，在其附近地区已经发生了几次大于M5（里氏）级的地震。安装在坝顶和下游坝坡的加速度计记录了坝体的反应。本文介绍了记录的加速度的时程曲线，根据这些记录数据评价了大坝动力特性。采用两种模型对大坝动力反应进行了评价。     

美国里弗水库大坝查找渗漏源的新方法

土坝渗漏预示着存在安全隐患,必须准确确定渗漏点和渗漏情况,以便采取补救措施,但一般采用的确定渗漏源的方法既费钱又费时。介绍了美国里弗水库大坝查找渗漏源的新方法。     

加强尚扎流域的水资源管理

西班牙西南部78m高的安德瓦洛堆石坝的投入运行对加强尚扎流域水资源的管理和利用将起到重要的作用。大坝将有助于满足旅游业和农业繁荣兴旺的区域内快速增长的供水需求。未来计划修建一座电厂。     

The paradox of plows and productivity: an agronomic comparison of cereal grain production under Iroquois hoe culture and European plow culture in the seventeenth and eighteenth centuries

Iroquois maize farmers in the seventeenth and eighteenth centuries produced three to five times more grain per acre than wheat farmers in Europe. The higher productivity of Iroquois agriculture can be attributed to two factors. First, the absence of plows in the western hemisphere allowed Iroquois farmers to maintain high levels of soil organic matter, critical for grain yields. Second, maize has a higher yield potential than wheat because of its C4 photosynthetic pathway and lower protein content. However, tillage alone accounted for a significant portion of the yield advantage of the Iroquois farmers. When the Iroquois were removed from their territories at the end of the eighteenth century, US farmers occupied and plowed these lands. Within fifty years, maize yields in five counties of western New York dropped to less than thirty bushels per acre. They rebounded when US farmers adopted practices that countered the harmful effects of plowing.     

Cocreating business's new social compact

Moving beyond decades of mutual distrust and animosity, corporations and nongovernmental organizations (NGOs) are learning to cooperate with each other. Realizing that their interests are converging, the two sides are working together to create innovative business models that are helping to grow new markets and accelerate the eradication of poverty. The path to convergence has proceeded in three stages. In the initial be-responsible stage, companies and NGOs, realizing that they had to coexist, started to look for ways to influence each other through joint social responsibility projects. This experience paved the way for the get-into-business stage, in which NGOs and companies sought to serve the poor by setting up successful businesses. In the process, NGOs learned business discipline from the private sector, while corporations gained an appreciation for the local knowledge, low-cost business models, and community-based marketing techniques that the NGOs have mastered. Increased success on both sides has laid the foundation for the cocreate-business stage, in which companies and NGOs become key parts of each other's capacity to deliver value. When BP sought to market a duel-fuel portable stove in India, it set up one such cocreation system with three Indian NGOs. The system allowed BP to bring the innovative stove to a geographically dispersed market through myriad local distributors without incurring distribution costs so high that the product would become unaffordable. The company sold its stoves profitably, the NGOs gained access to a lucrative revenue stream that could fund other projects, and consumers got more than the ability to sit down to a hot meal-they got the opportunity to earn incomes as the local distributors and thus to gain economic and social influence.