黄原酯棉对痕量银吸附条件的探讨     

张然  蒋小燕 《江西地质》2001,15(3):238-240

本文通过黄原酯棉对痕量银在不同条件下的吸附试验，找出黄原酯棉对痕量银吸附的最适宜条件，为在分析化学以及环保中利用黄原酯棉分析痕量银提供参考。  相似文献   

改性蒙脱石吸附Pb^2＋、Hg^2＋的实验研究   总被引：8，自引：0，他引：8  

王毅  王艺  王恩德 《岩石矿物学杂志》2001,20(4):565-567

对蒙脱石进行化学改性后生成的硫代蒙脱石热稳定性好，并且对金属离子Pb^2 、Hg^2 有很好的吸附性能，是一种处理污水中有害金属离子有效的矿物材料。  相似文献   

Evaluation of Experimental Procedures and Discussion of Two Different Modelling Approaches with Respect to Long-term Kinetics of Metal Cation Sorption onto (Hydr)oxide Surfaces     

Johannes Lützenkirchen 《Aquatic Geochemistry》2001,7(3):217-235

Experimental procedures as well as literature data and modelling of long-term kinetics of metal ion adsorption processes onto thermodynamically stable (hydr)oxide surfaces from aqueous solution are evaluated. It is concluded that when experimental uptake data are obtained by the solution depletion method precise information on experimental procedures is crucial. This is true both for preliminary kinetics studies (which intend to fix an equilibration time used for subsequent thermodynamic studies) and for true kinetic studies. For the usually given adsorption versus time curves the corresponding (possibly changing) values of pH should be added. The use of sorption pH edges measured at different times to obtain kinetics curves at constant pH may not correspond to the actual behaviour of the system but be rather an artificial construct.Concerning the models two basically different mechanisms have been used to account for the slow sorption step, which occurs in long-term studies: intraparticle diffusion of the adsorbing metal cation and slow redistribution of surface species. It is shown that the two mechanisms cannot be distinguished using macroscopic uptake data alone: data, which have been interpreted using one approach, may equally well be interpreted using the other one.  相似文献   

Retention of fly ash-derived copper in sediments of the Pandu River near Kanpur,India     

D. V. Ravi Chander  C. Venkobachar  B. C. Raymahashay 《Environmental Geology》1994,24(2):133-139

A coal-based thermal power plant is situated on the bank of the Pandu River, which is a tributary to the Ganges near Kanpur. River sediments downstream from the ash pond outfall are contaminated by fly ash. In order to establish the role of soils and sediments in retaining fly ash-derived heavy metals, copper was investigated as a model metal. A maximum concentration of 70 ppm Cu could be leached from the fly ash, confirming that it is a major source of this metal. Soil samples and river sediments were examined for Cu adsorption in the natural state as well as after treatment with H₂O₂, EDTA, and H₂O₂ followed by EDTA. The organic fraction of the samples was determined, and it had a major control on removal of Cu from a solution with 10^–4 M initial concentration. Further characterization of organic matter indicated that with reference to natural samples, the humic acid fraction had a copper enrichment factor in the range 9.1–15.1. The factor for fulvic acids, in contrast, was between 3.5 and 5.5. This leads to the conclusion that river deposits rich in humic acids would withstand relatively high metal loads. Only when the metal input exceeds the maximum retention potential, would the metal be fractionated into the aqueous phase and act as a potential biocide.  相似文献   

宝山矿田铜演化的地球化学过程探讨     

李正勤 《矿物岩石》1990,10(4):75-80

湖南省桂阳县宝山泥炭质岩系中铜的丰度大大超过火成岩和地壳,是成矿的重要物质来源。铜以炭质吸附和固溶胶形式赋存于地层中,因酸性水溶液侵蚀而分解析出,并渗入地下深处参加热液成矿作用。热液系硫化矿遭风化剥蚀而解体,大量的铜在还原带富集,部分以固溶胶或炭质吸附存在于泥炭质岩系中。原泥炭质岩系中的铜,至少有一部分参加了上述演化的地球化学作用。  相似文献   

三氮循环与地下水污染——以辛店地区为例   总被引：3，自引：0，他引：3  

邱汉学  刘贯群  焦超颖 《中国海洋大学学报(自然科学版)》1997,(4)

以往对三氮循环转化的室内实验表明吸附作用在浅表地带起很大作用。对辛店地区的实际资料研究表明，包气带岩性、厚度、理化性质对三氮的吸附与转化起着决定性作用。进入地下水中的三氮因受到水中污染物种类、数量，氧化还原条件的影响，可呈氧化或还原状态。  相似文献   

两种大型海藻粉对重金属离子吸附热力学的研究   总被引：4，自引：0，他引：4  

徐鲁荣  陈丽丹  钱爱红  李鹏  王宪  李文权 《台湾海峡》2003,22(4):493-498

本文探讨了两种常见大型海藻，即马尾藻(Sargassum fusiforme)和海带(Laminaria japonica)对重金属离子(Cu^2 、Pb^2 、Cd^2 、Ni^2 )的吸附热力学过程．结果表明，这两种海藻粉对重金属离子的吸附曲线基本符合Langmuir吸附模型，其吸附容量受温度的影响，马尾藻和海带粉对Cu^2 的吸附均为吸热过程；25℃和35℃两组实验结果显示，其吸附容量随温度的升高而增加，吸附热分别为59．9、76．8kJ／mol．  相似文献   

Characterization of the groundwater flow regime and hydrochemistry of groundwater from the Buem formation,Eastern Ghana     

Sandow Mark Yidana  Bruce Banoeng‐Yakubo  Thomas Akabzaa  Daniel Asiedu 《水文研究》2011,25(14):2288-2301

This study demonstrates the application of multivariate statistical methods in definition of groundwater recharge and discharge areas in a sedimentary basin in Ghana. Q‐mode hierarchical cluster analysis (HCA) was applied to 57 hydrochemical data from the Buem formation in the northern part of the Volta Region in Ghana. R‐mode HCA and R‐mode factor analysis were then applied to the same dataset to reveal the processes controlling the hydrochemistry of groundwater from this hydrogeological formation. Results of both the Q‐ and R‐mode analyses were backed by graphical methods. The analyses revealed two major water types, differentiated by salinity levels into four spatial groundwater associations. The characteristics of the four groundwater types are discussed. The recharge areas are characterized by Ca? HCO₃ low salinity waters which evolve through rock–water interactions to Na? HCO₃ high salinity waters in the discharge areas. This study finds that the hydrochemistry of groundwater from this formation is mainly controlled by the weathering of minerals, principally silicates in the aquifer matrix. The effects of the chemistry of recharging precipitation are higher in the recharge areas, while mineral weathering tends to be severe close to the discharge areas in the groundwater flow regime. All the four spatial groundwater associations have low sodium content, but salinity levels increase towards the discharge areas, such that some of wells in the discharge areas may not be acceptable for irrigation on grounds of high salinities which might affect the osmotic potentials of plants. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Uncertainty of gas saturation estimates in a subbituminous coal seam     

Tennille E. Mares  Tim A. Moore  Catherine R. Moore 《International Journal of Coal Geology》2009,77(3-4):320-327

To assess the commercial viability of a coalbed methane prospect two of the key geological parameters measured are gas content (desorbed gas) and gas holding capacity (adsorption capacity). These two measures, together with reservoir pressure, give an estimate of the gas saturation of the reservoir. Typically gas saturation has been assessed by collecting one adsorption isotherm sample and assuming it is representative of the whole seam reservoir conditions. This study addresses that assumption.To understand the level of variation, and thus the inherent uncertainty in saturation, one core (Jasper-1) from the Huntly coalfield in New Zealand was analysed in detail. Ten samples (representing the whole coal seam) were placed into gas desorption canisters and desorbed for ten days and then analysed for adsorption capacity. Desorption analyses for total measured gas content (average in-situ basis) ranged from 2.32 to 2.89 m³/t (standard deviation (sd) = 0.18) and gas adsorptive capacity at 4 MPa (average in-situ basis) from 2.11 to 3.51 m³/t (sd = 0.38) resulting in saturations ranging from 66% to 120% (sd = 15).Determination of how many samples are required to make a realistic assessment of average reservoir properties requires a consideration of: (i) the level of accuracy desired, (ii) the limit of accuracy possible, which is governed by the magnitude of experimental error, and (iii) the innate variability of the seam. It was found that a minimum of five samples each for adsorption and desorption were required in order to significantly decrease the uncertainty in gas saturation estimates for a subbituminous coal.  相似文献   

RETRACTED ARTICLE: The hydrochemical framework of surface water basins in southern Ghana     

Sandow Mark Yidana 《Environmental Geology》2009,57(4):789-796

Surface water resources play a crucial role in the domestic water delivery system in Ghana. In addition, sustainable food production is based on the quality and quantity of water resources available for irrigation purposes to supplement rain-fed agricultural activities in the country. The objective of this research was to determine the main controls on the hydrochemistry of surface water resources in the southern part of Ghana and assess the quality of water from these basins for irrigation activities in the area. R-mode factor and cluster analyses were applied to 625 data points from 6 river basins in southern Ghana after the data had been log transformed and standardized for homogeneity. This study finds that surface water chemistry in the south is controlled by the chemistry of silicate mineral weathering, chemistry of rainfall, fertilizers from agricultural activities in the area, as well as the weathering of carbonate minerals. A Gibb’s diagram plotted with total dissolved solids (TDS) on the vertical axis against (Na⁺ + K⁺)/(Ca²⁺ + K⁺ + Na⁺) on the horizontal axis indicates that rock weathering plays a significant role in the hydrochemistry. Activity diagrams for the CaO–Na₂O–Al₂O–SiO₂–H₂O and CaO–MgO–Al₂O₃–SiO₂–H₂O systems suggest that kaolinite is the most stable clay mineral phase in the system. In addition, an assessment of the irrigation quality of water from these basins suggests that the basins are largely low sodium—low to medium salinity basins, delivering water of acceptable quality for irrigation purposes.  相似文献