交联壳聚糖乙酸酯冠醚对金属离子的吸附性能研究

本文合成了二苯并-16-冠-5-氯代乙酸酯冠醚和3,5-二叔丁基-二苯并-14-冠-4-双氯代乙酸酯冠醚,然后分别将之与交联壳聚糖(简称CCTS)反应,制备了交联壳聚糖二苯并-16-冠-5-乙酸酯冠醚(简称CCTS-1)和交联壳聚糖3,5-二叔丁基-二苯并-14-冠-4-双乙酸酯冠醚(简称CCTS-2),并研究了它们对Pb~(2+),Cu~(2+),Cr~(3+),Ni~(2+),Cd~(2+)的吸附性能。结果表明:这两种吸附剂对pb~(2+),Cu~(2+)有较高的吸附选择性。     

The water-soluble fraction of potentially toxic elements in contaminated soils: relationships between ecotoxicity, solubility and geochemical reactivity

To better understand the impacts posed by soil contamination to aquatic ecosystems it is crucial to characterise the links between ecotoxicity, chemical availability and geochemical reactivity of potentially toxic elements (PTE’s) in soils. We evaluated the adverse effects of water extracts obtained from soils contaminated by chemical industry and mining, using a test battery including organisms from different trophic levels (bacteria, algae and daphnids). These tests provided a quick assessment of the ecotoxicity of soils with respect to possible adverse effects on aquatic organisms although the ecotoxicological responses could be related to the solubility of PTE’s only to a limited extent.The analysis of results of bioassays together with the chemical characterisation of water extracts provided additional relevant insight into the role of conductivity, pH, Al, Fe, and Mn of soil extracts on toxicity to organisms. Furthermore, an important conclusion of this study was that the toxicity of extracts to the aquatic organisms could also be related to the soil properties (pH, Org C and Fe_ox) and to the reactivity of PTE’s in soils which in fact control the soluble fraction of the contaminants.The combined assessment of ecotoxicity in water fractions, solubility and geochemical reactivity of PTE’s in soils provided a more comprehensive understanding of the bioavailability of inorganic contaminants than ecotoxicological or chemical studies alone and can therefore be most useful for environmental risks assessment of contaminated soils.     

累托石/氧化亚铜纳米复合材料的制备及光催化性能研究

以累托石为载体,用液相合成法制备了累托石/纳米氧化亚铜复合材料,采用SEM、XRD对其进行了表征,并以吸附降解亚甲基蓝的效果探讨了复合材料的吸附及光催化性能.结果表明,在最佳条件为:溶液呈碱性,亚甲基蓝初始浓度90 mg/L,复合材料用量1.33 g/L,温度60℃,反应20 mim时复合材料对亚甲基蓝的降解率可达到9...     

Geotechnical properties of municipal solid waste at different phases of biodegradation

This paper presents the results of laboratory investigation conducted to determine the variation of geotechnical properties of synthetic municipal solid waste (MSW) at different phases of degradation. Synthetic MSW samples were prepared based on the composition of MSW generated in the United States and were degraded in bioreactors with leachate recirculation. Degradation of the synthetic MSW was quantified based on the gas composition and organic content, and the samples exhumed from the bioreactor cells at different phases of degradation were tested for the geotechnical properties. Hydraulic conductivity, compressibility and shear strength of initial and degraded synthetic MSW were all determined at constant initial moisture content of 50% on wet weight basis. Hydraulic conductivity of synthetic MSW was reduced by two orders of magnitude due to degradation. Compression ratio was reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. Direct shear tests showed that the fresh and degraded synthetic MSW exhibited continuous strength gain with increase in horizontal deformation, with the cohesion increased from 1 kPa for fresh MSW to 16–40 kPa for degraded MSW and the friction angle decreased from 35° for fresh MSW to 28° for degraded MSW. During the triaxial tests under CU condition, the total strength parameters, cohesion and friction angle, were found to vary from 21 to 57 kPa and 1° to 9°, respectively, while the effective strength parameters, cohesion and friction angle varied from 18 to 56 kPa and from 1° to 11°, respectively. Similar to direct shear test results, as the waste degrades an increase in cohesion and slight decrease in friction angle was observed. Decreased friction angle and increased cohesion with increased degradation is believed to be due to the highly cohesive nature of the synthetic MSW. Variation of synthetic MSW properties from this study also suggests that significant changes in geotechnical properties of MSW can occur due to enhanced degradation induced by leachate recirculation.     

环形热岛格局演变过程的遥感分析

城市热岛效应的空间格局在一定程度上可以反映城市规划和管理的成败得失,也是城市大气污染的驱动因素之一。〖JP2〗使用2000、2003、2004、2006、2008和2010年2～3月下午成都的6次NOAA/AVHRR（National Oceanic and Atmospheric Administration/Advanced Very High Resolution Radiometer）卫星遥感数据反演亮温,采用均值 标准差法将热岛强度分为7个等级,用面积加权平均法将研究区强度分为高温、中温和低温3类。结果表明：（1）热岛空间格局呈现巨大变异,由前期的中心型演变为中期的环型,后期是热岛环的形态和高温中心的调整阶段;（2）研究区的强度为前期强,2004年迅速减弱,高温类的强度2004年比2003年减弱259℃,2004年之后的平均减弱率仅为024℃/a;（3）城市东北部和西南部高温区的温度梯度出现逆向升降趋势。由于地表温度对城市气温有重要影响,热岛形态的变化是人们从更复杂角度分析大气污染机制、设计热岛数值模型和进行城市规划的客观依据     

Simulation of aerosol direct radiative forcing with RAMS-CMAQ in East Asia

The air quality modeling system RAMS-CMAQ is developed to assess aerosol direct radiative forcing by linking simulated meteorological parameters and aerosol mass concentration with the aerosol optical properties/radiative transfer module in this study. The module is capable of accounting for important factors that affect aerosol optical properties and radiative effect, such as incident wave length, aerosol size distribution, water uptake, and internal mixture. Subsequently, the modeling system is applied to simulate the temporal and spatial variations in mass burden, optical properties, and direct radiative forcing of diverse aerosols, including sulfate, nitrate, ammonium, black carbon, organic carbon, dust, and sea salt over East Asia throughout 2005. Model performance is fully evaluated using various observational data, including satellite monitoring of MODIS and surface measurements of EANET (Acid Deposition Monitoring Network), AERONET (Aerosol Robotic Network), and CSHNET (Chinese Sun Hazemeter Network). The correlation coefficients of the comparisons of daily average mass concentrations of sulfate, PM2.5, and PM10 between simulations and EANET measurements are 0.70, 0.61, and 0.64, respectively. It is also determined that the modeled aerosol optical depth (AOD) is in congruence with the observed results from the AERONET, the CSHNET, and the MODIS. The model results suggest that the high AOD values ranging from 0.8 to 1.2 are mainly distributed over the Sichuan Basin as well as over central and southeastern China, in East Asia. The aerosol direct radiative forcing patterns generally followed the AOD patterns. The strongest forcing effect ranging from −12 to −8 W m⁻² was mainly distributed over the Sichuan Basin and the eastern China’s coastal regions in the all-sky case at TOA, and the forcing effect ranging from −8 to −4 W m⁻² could be found over entire eastern China, Korea, Japan, East China Sea, and the sea areas of Japan     

宋至清荆江南岸分流四口的演变

在历史时期荆江地区的经济开发与江湖关系的演变历程中,分流诸口是极其重要的影响因素。以宋至清的志书为主要资料,立足于历史学的实证方法,以今荆江南岸存在的4个分流穴口,即虎渡口、调弦口、藕池口和松滋口为主要对象,考察四口在宋元明清时期的分塞情况,并对今人存在的一些认识进行了辨析。其中,虎渡河的形成时间说法不一,南宋以后,虎渡口逐渐形成稳定分流。调弦口自元代大德年间开浚后时开时塞,直至清朝才基本保持分流,1958年调关设置后此口渐废。藕池口早在五代时即已存在,北宋以后湮塞,直至1852年藕池堤溃不筑,藕池河再次形成。松滋河则在1869年以前由于黄家埠堤溃决而形成。研究表明,宋代以降,四口的分塞情况较为复杂,因此,考察荆江穴口分流与湮塞的历史变迁,厘清以往的相关歧见,将有助于更正确、客观地理解今天的人地关系、江湖关系的格局及其走向。     

矿化垃圾基本理化性状剖面变化特征研究

矿化垃圾能否作为农业资源被重新利用,除应考虑有效植物营养物质的含量与是否存在有害物质外,还取决于其基本理化性状。对城市生活垃圾填埋场中经填埋6年、8年、10年后得到的矿化垃圾基本物化性状变化特征进行分析,结果表明:矿化垃圾的土粒密度显著小于对照土壤,交换性盐基总量、CEC显著大于对照土壤,pH值和对照土壤基本相当;表层(0~50 cm)矿化垃圾的土粒密度、CEC、交换性盐基总量、pH值的变化幅度依次大于中层(50~100 cm)和下层(100~150 cm);矿化垃圾的理化性状在填埋8~10年后总体趋于稳定。从植物生长的环境角度看,填埋8~10年后的矿化垃圾可以开采后作为植物生长基质、土壤改良剂等农业资源化利用。     

怀化城市形态的演变特征及形成机制

根据城市规划土地利用现状图、怀化市1〖DK1〗∶10 000地形图、遥感影像图、社会经济统计数据以及其他相关资料,借助ArcGIS 92平台和统计分析软件(SPSS 115),采用空间形态分析、地统计分析、等扇分析、景观测度及分形理论等研究方法,对我国中部铁路枢纽城市怀化的城市形态演变特征及形成机制展开研究。结果表明：城市形态的紧凑度、分维数偏低,形状指数偏大,城市以正东、西南、正北方位的扩展为主,演化轨迹为“据点型”-“散点组团型”-“团城型”-“枝状放射型”-“‘T’字型”;城市形态演变是经济发展、交通设施发展、自然地理条件限制等多重驱动力共同作用的结果.     

Sulfonated tea waste: A low-cost adsorbent for purification of biodiesel

In the present work, the crude biodiesel produced from spent fish frying oil through alkaline catalyzed transesterification was purified using a low-cost adsorbent viz. sulfonated tea waste. After separating the glycerol, the crude biodiesel was purified using the suggested adsorbent. Various methods of purification using the said adsorbent were applied such as purification using adsorption column chromatography and shaking methods. The results showed that purification using adsorption column chromatography exhibited the bst result. Properties of the purified fuels were determined and found conformed to those specified by the ASTM standards. For the sake of comparison, purification using zeolite and water washing method was also investigated. The result indicated that the suggested adsorbent was more successful on purification of the crude biodiesel compared to other methods.