离子液体调控溶剂热合成TiO₂纳米颗粒及紫外-可见光催化降解性能          下载免费PDF全文

杜记民  赵国燕  李亚晓  毛彦君  钱永腾  何稳  李志双 《盐湖研究》2012,20(4):30-35

以钛酸四丁酯(TEOS)、去离子水为原料,离子液体1-丁基-3-甲基四氟硼酸咪唑盐([Bmim]BF4)为表面活性剂,通过溶剂热法制备了锐钛矿相TiO2纳米颗粒。用X-射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见吸收光谱仪(UV-Vis)对产物的晶相、形貌和光学性能进行表征。为了评估光催化活性,并以甲基橙水溶液为研究对象,在紫外光照射下分析不同照射时间下光降解效率。结果表明,离子液体、去离子水和钛酸四丁酯的体积比为1.3∶1∶1.3时,反应所得到的TiO2具有较高光催化活性,明显优于未添加离子液体的产品,这一结果可归因于其具有较大的比表面积。  相似文献   

锂离子电池硅基负极材料研究进展          下载免费PDF全文

张利 《盐湖研究》2012,20(1):64-72

硅是青海省储量丰富的资源之一,因其储锂容量高、安全性能优越,而成为锂离子电池理想的负极材料,但由于硅在深度嵌脱锂时体积效应大,易与导电介质、集流体失去电接触,造成电极循环性能迅速下降。对抑制其体积效应、增加其电导率的"低维化"和"复合化"两种技术进行了介绍。  相似文献   

Influences of land use history and short-term nitrogen addition on community structure in temperate grasslands     

《Journal of Arid Environments》2012

Better understanding of plant community structure in relationship to land use history and nitrogen (N) will facilitate grassland conservation and projections of community succession under future N deposition. We conducted a field experiment in northern China to examine the influence of 2-year N addition on species composition and community structure in three temperate grasslands with different land use history: steppe fenced for two years (ST), steppe fenced for five years (SF), and old field grassland fenced for five years (OF). The results showed previous farming reduced species diversity and plant cover, which is mainly caused by decrease in perennial grasses (PG) and forbs (PF). Nitrogen addition increased plant cover, especially the PG cover, but had little effects on species diversity. Nitrogen enrichment also has a tendency to alter community composition by decreasing proportional cover of PF but increasing that of PG and annuals and biennials (AB), suggesting enhanced dominance of PG under increasing N deposition. Irrespective of the short-term (2 years) experimental periods, our findings highlight the dominant role of land use history in structuring plant community, and have valuable implications for grassland conservation and model projections of ecosystem succession under global scenarios of N deposition in the semi-arid grasslands.  相似文献   

Hydrocarbons generated by hydropyrolysis of suspended marine particulate organic matter: Relationship to the oceanography of the Black Sea and the Rhodes Gyre     

Yeşim Çoban-Yildiz  Alec F. Gaines  Pat E. Keating  Gordon D. Love  Dennis McLoughlin  Colin E. Snape 《Organic Geochemistry》2009,40(2):270-282

The suspended particulate organic matter, SPOM, in the autumnal Black Sea has been characterised using catalytic hydropyrolysis (HyPy) of the total (bound plus free) lipid material. The technique, which generates maximum yields of volatile products from sediments, kerogens and phytoplankton, was followed using gas chromatography and gas chromatography/mass spectrometry. The generated alkanes were dominated by n-C₁₈, hypothesised to arise predominantly from unsaturated C₁₈ fatty acids. Steranes were generated from reductive conversion of free and bound sterols. The generation of branched alkanes and especially of hopanes provided formal evidence for the participation of bacteria in the mineralisation of the SPOM. Whereas similar distributions of n-alkanes were generated from SPOM sampled from different depths of the comparatively well-stirred Rhodes Gyre (eastern Mediterranean), mineralisation of the SPOM at each depth of the central Black Sea produced characteristic changes in the composition and concentration of the HyPy products. Depth profiles of the n-alkanes generated from SPOM in the region of the Rim Current were affected by the local hydrography. Polynuclear aromatic hydrocarbons (PAHs) of anthropogenic origin were present in the surface waters of the central Black Sea. Some methyl benzenes, thiophenes and pyrroles were also generated.  相似文献   

电感耦合等离子体质谱法测定井间示踪剂中稀土元素   总被引：5，自引：3，他引：2  

曹煊  李景喜  俞晶晶  于振花  陈维余  杨黄浩  王小如 《岩矿测试》2009,28(2):91-96

以甲醇为稀释剂,用电感耦合等离子体质谱法快速测定稀土示踪剂中17个稀土元素。研究表明,在优化的稀释剂甲醇浓度为2%(体积分数)、pH<2.47的条件下测定稀土元素,方法精密度(RSD)为1.23%~2.83%,日间6次测定的精密度为2.25%~4.76%,各稀土元素线性关系良好,检出限为2.0~9.0 ng/L;17个稀土元素的加标回收率为85%~108%,满足痕量元素分析要求。  相似文献   

矿物白度的影响因素与增白机理研究     

汪灵  胡晓宙  王哲皓 《岩石学报》2019,35(1):137-145

白度是矿物的重要光学性质之一。为了深化矿物的光学性质及白色矿物功能材料的研究与应用,根据测试分析结果和叶大年的结构光性矿物学理论,系统研究了影响矿物白度的主要因素,以及矿物增白效果的差异性及其产生机理。研究结果表明:(1)晶体化学是决定不同种类透明矿物白度的最主要因素,但对于某种透明矿物来说,影响其白度的主要因素是矿物中的碳质有机质、含铁钛矿物杂质、杂质元素的价态与晶体化学环境、介质环境、矿物中的水和粒度大小等。(2)证明了透明矿物白度大小与折射率呈正相关。白度相同的不同矿物的增白效果存在很大差异性,其根本原因是由矿物折射率所决定的反射率存在很大差别。(3)提出了真白度和假白度的概念,即主要由自色产生的白度称为真白度,主要由假色产生的白度称为假白度;真白度高的矿物具有增白作用,而真白度低的矿物,即使粉末白度高,也没有增白作用。(4)在影响矿物白度的主要因素中,矿物中的碳质有机质、含铁钛矿物杂质、杂质元素的价态等杂质成分对矿物白度和增白效果起负面作用。(5)矿物中与晶体结构相关的水所产生的颜色属于自色,脱去结晶水、层间水和结构水都有利于提高矿物的真白度或增白效果,但脱去沸石水的效果正好相反;由矿物粒度大小变化产生的颜色属于假色;通过降低粉体粒度大小所提高的白度属于假白度,由此增加的白度没有增白作用。另外,矿物粉体与使用介质之间的折射率大小差别越大,增白效果越明显。  相似文献   

Institutions for Global Environmental Change     

《Global Environmental Change》2001,11(2):175

  相似文献   

Soil Resources and the Environment: U Aswathanarayana; Enfield: Science Publishers Inc., 1999, ISBN 1-57808-067-3     

《Applied Geochemistry》2001,16(7-8):1001

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Arsenic speciation in surface waters and sediments in a contaminated waterway: an IC–ICP-MS and XAS based study     

《Applied Geochemistry》2003,18(9):1387-1397

An integrated approach involving the use of ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS), X-ray absorption spectroscopy (XAS) and sequential extraction procedures has been employed to elucidate the solution and solid phase speciation and partitioning of As in a polluted urban watercourse. Dissolved As concentrations exceeding 130 μg l⁻¹ and comprising entirely inorganic species were determined in the waters of Tinker Brook, a contaminated stream. Upon mixing with a relatively As-free stream, White Ash Brook, both the total concentration of dissolved As and the proportion of As(V) were observed to decrease dramatically below values expected for conservative mixing. This was ascribed to adsorption onto the Fe (oxyhydr)oxides that characterise White Ash Brook on the basis of sequential extraction and direct analysis of the solids via XAS . The shift in oxidation state is speculated to be due to the faster rate of adsorption of As(V) on Fe (oxyhydr)oxides than As(III) in this fast flowing stream system. During periods of reduced supply of anthropogenic As, a small, secondary input of As(III) to White Ash Brook is detectable, delivered by a small ochreous seepage. The Fe (oxyhydr)oxide As-rich deposits surrounding this discharge may also act as a significant source of As upon dissolution during stormflow conditions.  相似文献   

The ecological footprint: a non-monetary metric of human consumption applied to North America     

《Global Environmental Change》2003,13(2):83-100

This paper employs ecological footprint analysis as a potential non-monetary metric of human consumption and ecological productivity in a simulation-modeling framework, applied to North America. The ecological footprint provides an indirect basis for considering the long-term ecological risk and sustainability of human settlements, regions or, in this case, a continent. We examine several scenarios for human consumption, ecological productivity and material efficiency, to explore which variables have influence on the ecological budget of North America over the coming century. Only one scenario, which assumes considerable reductions in human consumption, is likely to yield an ecological surplus. Unlike monetary measures of societal well-being, ecological footprint analysis shows that increased economic activity and consumption creates deficits in terms of the balance of ecological productivity and consumption in a region, and may reduce long-term ecological sustainability. Several advantages and disadvantages of this metric are discussed.  相似文献