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研究了卤水中有机物在吸附剂氢氧化锆上的吸附行为。测定了氢氧化锆对有机物在不同温度下的吸附等温线,利用热力学函数关系计算出了吸附焓、自由能和熵变,并探讨了有机物与氢氧化锆的吸附作用机理。实验结果表明,氢氧化锆对有机物的吸附等温线符合Langmuir等温吸附方程;吸附动力学数据符合拟二级反应动力学模型;吸附焓变ΔH及吸附自由能变ΔG分别在-15~-10 k J/mol及-20~0 k J/mol范围内,表明氢氧化锆对卤水中有机物的吸附属于自发的物理吸附过程,且吸附过程主要为范德华力吸附及氢键吸附,经脱附再生后的氢氧化锆可完全恢复其形态特征及吸附能力。 相似文献
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以亚铁氰化钾为单源前驱体,以活性炭为载体,采用超声辅助均匀沉淀法,制备了普鲁士蓝/活性炭复合材料(PB/AC)。通过场发射扫描电子显微镜、X-射线衍射、X-射线光电子能谱和傅立叶变换红外光谱技术,对PB/AC的形貌、结构和组成进行了表征。结果表明:立方体结构的PB微晶均匀地分布在活性炭表面。研究考察了PB/AC对水溶液中铯离子(Cs~+)的吸附和脱附性能。在pH=7、45℃和180 min条件下,PB/AC对Cs~+的最大吸附量为49.17 mg/g;在pH=2、45℃和240 min条件下,Cs~+的脱附率可达88.5%。 相似文献
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以高锰酸钾和一水硫酸锰为原料,采用水热合成法,合成得到了花状和海胆状纳米二氧化锰吸附剂。研究了两种吸附剂对三价砷的吸附选择性、循环利用性及除砷机理。结果表明,阴离子对花状和海胆状吸附剂吸附三价砷的影响顺序略有不同,其分别为PO■ CO■HCO~-_3NO~-_3SO■Cl~-,PO■HCO■SO■CO■NO~-_3Cl~-;花状和海胆状二氧化锰经三次循环再生后的除砷率分别为65.5%和75.1%;两种吸附剂对三价砷的吸附机理主要为氧化吸附作用。 相似文献
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研究了竹炭对水溶液中乙酰甲胺磷的吸附性能,考察了吸附时间、竹炭用量、粒径、溶液pH值和乙酰甲胺磷初始浓度对吸附效果的影响以及竹炭的再生性能．结果表明：竹炭对乙酰甲胺磷的吸附主要受竹炭用量、粒径、溶液初始浓度的影响,酸性条件有利于竹炭对乙酰甲胺磷的吸附．竹炭对乙酰甲胺磷的动态吸附过程符合二级吸附动力学方程．粒径为0．3～0．15mm的竹炭对乙酰甲胺磷的吸附主要发生在50min之内,此后吸附率变化很小．竹炭对乙酰甲胺磷的吸附符合Langmuir和Freundlich吸附等温方程．吸附后的竹炭进行碱法再生后,其吸附率可达原来的93．6％． 相似文献
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首先通过水热合成制备了六方隧道结构的WO3,然后再通过两步法将LiV3O8与WO3进行复合,制备成WO3/LiV3O8复合材料。随后采用XRD、SEM、EDS等手段对该复合材料进行了结构表征,并考察了不同复合比例的WO3/LiV3O8电控离子交换(ESIX)性能。实验结果表明,LiV3O8与WO3成功复合,其中WO3 (10%)/LiV3O8 的电化学性能最佳。将WO3 (10%)/LiV3O8 涂覆到预处理好的碳纸上,制备成电活性功能膜,采用ESIX技术在30 mg/L的含Li+溶液中对Li+进行电化学吸附,在电位为-1.0 V(vs. SCE)时吸附容量最大,为14.2 mg·g-1。在三种离子浓度均为0.015 mol/L 的Li+、Mg2+、K+混合溶液中测试了该材料的选择性,Li+/Mg2+和Li+/K+的选择性系数分别为15.88和52.23,五次吸附-脱附循环后,Li+的吸附容量仍能保持初始容量的87.8%。WO3/LiV3O8对Li+吸附表现出较高的吸附选择性,且复合材料具有一定的可重复使用性。 相似文献
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近年来,随着科学技术进步和锂离子电池的大规模应用,市场对锂的需求快速增长。由于固体矿产锂资源有限,锂提取技术的重点已转移到盐湖卤水资源中,因此研究盐湖提锂技术具有重要价值。在现有的各种锂提取技术中,吸附法因其制备工艺简单,成为从盐湖卤水中回收锂的最有效、最环保的方法之一。而基于锂离子筛的吸附法因其吸附选择性高、再生性能好、低能耗和环保等优点被认为是最有前途的提锂方法。文章综述了锰系锂离子筛的结构特点和制备方法等该领域的最新研究进展,同时还着重讨论了锰系锂离子筛的成型技术和相关研究进展,并对离子筛工业应用中存在的不足进行了总结和展望。 相似文献
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Li Geng Qin Yong Yao Haipeng Zhou Xianqing Xiao Xiaohu Zhang Zhen 《Natural Resources Research》2021,30(6):4477-4491
In this study, the pore characteristics and the factors of maximum methane adsorption capacity (MAC) of mudstone in the early diagenetic stage (EDS) and the contribution rate of clay mineral (CM) adsorption were analyzed. In addition, the adsorption coupling effect of CM and organic matter (OM) was discussed. Studies have shown that pores of coal measure mudstone in the early diagenesis stage are mainly small pores with slanted platelike staggered and overlapped pores, with more pore opening directions. The main controlling factors of the maximum MAC of mudstone are OM and CM, and the direct expression is the pore surface area. In the EDS, the contribution rate of CM in mudstone is lower, while the contribution rate of OM to the MAC of mudstone is higher. There is an adsorption coupling effect of CM composition and OM. OM in mudstone is scattered, and the CMs have a supporting effect, which leads to OM in mudstone having a large contact area with the open space and has many effective pores. OM in coal is concentrated, and the surface area of OM per unit volume is small (compared with OM in mudstone). The compaction and deformation characteristics of CMs have a plugging/sealing effect on the pores of OM in the coal, which makes the effective pores of OM per unit volume in coal lower than those in mudstone.
相似文献12.
通过测试不同Cl~-(NaCl)掺量磷酸镁水泥(MPC)浸取液中离子浓度及MPC硬化体的孔结构和吸水率,研究了Cl~-掺量和浸取时间对MPC硬化体平均孔径、孔隙率、孔径分布、孔体积分布、吸水率、MPC浸取液中Cl~-、Na~+、OH~-、Mg~(2+)、PO■和K~+浓度的影响,结果表明外掺Cl~-对MPC孔结构、离子溶出及吸水率有显著影响,当Cl~-掺量为1%时,MPC硬化体结构密实、孔隙率低、平均孔径小、吸水率小、MPC水化产物在水中的溶蚀量小。 相似文献
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Gunn M. G. Teige Christian Hermanrud Lars Wensaas Hege M. Nordgård Bolås 《Basin Research》2007,19(1):33-50
Methods for detection of pore fluid overpressures in shales from seismic data have become widespread in the oil industry. Such methods are largely based on the identification of anomalous seismic velocities, and on subsequent determination of pore pressures through relationships between seismic velocities and the vertical effective stress (VES). Although it is well known that lithology variations and compaction mechanisms should be accounted for in pore pressure evaluation, a systematic approach to evaluation of these factors in seismic pore pressure prediction seems to be absent. We have investigated the influence of lithology variations and compaction mechanism on shale velocities from acoustic logs. This was performed by analyses of 80 wells from the northern North Sea and 24 wells from the Haltenbanken area. The analyses involved identification of large‐scale density and velocity variations that were unrelated to overpressure variations, which served as a basis for the analyses of the resolution of overpressure variations from well log data. The analyses demonstrated that the overpressures in neither area were associated with compaction disequilibrium. A significant correlation between acoustic velocity and fluid overpressure nevertheless exists in the Haltenbanken data, whereas the correlation between these two parameters is weak to non‐existing in the North Sea shales. We do not presently know why acoustic velocities in the two areas respond differently to fluid overpressuring. Smectitic rocks often have low permeabilities, and define the top of overpressures in the northern North Sea when they are buried below 2 km. As smectitic rocks are characterized by low densities and low acoustic velocities, their presence may be identified from seismic data. Smectite identification from seismic data may thus serve as an indirect overpressure indicator in some areas. Our investigations demonstrate the importance of including geological work and process understanding in pore pressure evaluation work. As a response to the lack of documented practice within this area, we suggest a workflow for geological analyses that should be performed and integrated with seismic pore pressure prediction. 相似文献
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Electrical conductivity models for the continental crust based on laboratory measurements on high-grade metamorphic rocks 总被引：1，自引：0，他引：1
Summary. Deep electrical conductivity soundings are increasingly being used as an additional source of information regarding the nature of the lower continental crust. However, a lack of relevant laboratory-based conductivity measurements makes interpretation of such soundings difficult. Laboratory measurements have been made on saturated and unsaturated samples of possible lower crustal rock types subjected to confining pressures up to 0.4 GPa, temperatures up to 300°C, and with variable pore fluid pressure up to the confining pressure. Extrapolation of these results suggests that the surprisingly high conductivities deduced for depths of approximately 20 km in certain stable continental areas may result from a combination of basic rock type and high pore fluid pressures, for whereas the conductivities measured in acid rock types can be explained in terms of conduction through the pore fluid alone, the conductivities measured in basic rock types imply enhanced conduction presumably through the matrix or along grain boundaries. The lower conductivities deduced from field experiments for the upper crust may be due to more acid rock types and/or lower pore fluid pressures, perhaps due to hydration reactions. In areas where the high conductivity layer is coincident with a low velocity layer an explanation in terms of changing pore fluid pressure, i.e. low to high, with increasing depth seems more likely. 相似文献
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《极地研究》1992,3(1):50-59
Remobilization and accumulation mechanisms of iodine in marine sediments, which are divided into several geochemical environment, are studied. The result shows that iodine is characteristically rich in organic fractions of the sediments on the bottom of bay and pelagic sediments. However, it may be associated with oxyhydroxide and adsorptive phase in a highter percentage at the continental shelf and hemipelagic sediments. The environmental characteristics of remobilization of iodine in surficial sediments are similar to that of iron, that is, it is remobilized on anoxic conditions and converted into solid phases when it is in oxic environments, though the iodine does not act as the electron acceptor. The processes of adsorption and oxidation are responsible for the value of I_t/C_(org) in excess of that of planktonic materials other than the organic fraction in surficial sediments. It is a comprehensive effect of organism decomposition, oxyhydroxide reduction, particulate adsorption and pore water diffu 相似文献
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本文研究了西南极不同地理环境沉积碘的地球化学迁移和富集机制 ,结果表明海湾和深海表层沉积物碘主要与有机质结合 ,但在陆架和半深海 ,与氧化物结合和吸附态碘可占相当大的比例。碘在表层沉积物中迁移的环境特征与铁类似 ,即在还原环境中迁移 ,在氧化环境中转入固相 ,然而碘在沉积物中主要并不是作为电子接受者 ,而是随有机质分解或氧化物还原后被释放进入液相。沉积物表层 I/Corg值高于浮游生物是由于吸附和氧化过程的参与。沉积物 I/Corg值随深度的降低代表了有机质分解 ,氧化物还原 ,粘粒物质解析及间隙水碘扩散的综合效应。沉积物碘的扩散通量与沉积通量在同一数量级水平解释了沉积岩贫碘的原因。根据计算和讨论结果重新提出了海洋沉积物碘迁移和富集的地球化学模式。 相似文献
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Heat capacities of solid sediments and pore fluids within a basin can influence geothermal gradients when sedimentation or erosion is rapid. This paper provides data on specific heat capacities of pore fluids and porous rocks. It includes data on specific heat capacities of water, ice, and gas hydrates at reference temperatures, as well as equations for calculating the specific heat capacity of those substances as a function of temperature. It also provides values for specific heat capacities of oil and natural gases at low temperatures, as well as equations describing the temperature and pressure dependence of the specific heat capacities of those substances. Finally, it shows how to calculate the specific heat capacity of mixtures of solid materials, or of mixtures of solids and pore fluids. The data and equations provided herein can be incorporated directly into existing modeling software by users and software developers. 相似文献
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采用静态试验法研究了水溶性富勒烯对U(VI)在氧化多壁碳纳米管上吸附的影响。结果表明,羟基化富勒烯(C60(OH)n)和羧基化富勒烯(C60(C(COOH)2)n)的加入对U(VI)在氧化多壁碳纳米管上的吸附量影响作用类似。在pH<3范围内,羟基化富勒烯和羧基化富勒烯对吸附几乎没有影响,在pH>3以后,二者开始抑制碳纳米管对U(VI)的吸附。较低浓度(10 mg/L)的C60(OH)n对U(VI)的吸附几乎没有影响。而等量的C60(C(COOH)2)n已呈现出明显的抑制作用。但两者的作用机理不同,前者可能是由于羟基化富勒烯和U(VI)竞争氧化多壁碳纳米管上的吸附位点造成的,后者则可能改变了氧化多壁碳纳米管的表面电荷。用双位点模型对不同固液比和U(VI)初始浓度下U(VI)的吸附率随C60(OH)n和C60(C(COOH)2)n初始浓度的变化进行了拟合得到了很好的结果。 相似文献
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西藏自治区农牧民收入结构分析 总被引：2，自引：1，他引：1
依据入户调查资料 ,文章重点分析了现阶段西藏农牧民的收入结构 ,包括收入来源、收入性质、现金收入等内容 ,探索了不同地区 (农区、牧区、半农半牧区、一江两河农业开发区、城郊区等 )及不同收入段农牧民收入结构和收入来源的差异。通过分析发现西藏农牧民收入有以下特征 :①收入以实物为主 ,现金收入和可支配收入少 ;②城郊区农牧民收入多样化指数高 ,农牧民收入高 ,收入多样化指数与农牧民收入正相关 ;③低收入农户收入来源单一 ,抗风险能力弱 ,收入增加困难 ;④从生活质量看农区优于牧区 ,半农半牧区农牧民生活质量最差 ;⑤影响农牧民人均收入的主要因子为人均生产性投入、区域通达度等。 相似文献
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Characteristics and origin of underpressure system in the Shiwu Fault Depression, south-east Songliao Basin, China 总被引：6，自引：0，他引：6
The vertical characteristics of underpressure, pore fluids and sealing condition in the Shiwu Fault Depression, south‐east Songliao Basin, are investigated. Based on the pore pressure data from drill stem tests collected from 40 wells, the vertical distribution of pore pressure in this depression consists of a shallow hydrostatic pressure system and a deep underpressure system. The observed low pressures range from about 4 to 10 MPa in the depth interval of about 1550–2800 m. The pore water chemistry data document that the ionic evaporite trends of the pore water in the underpressure zone are different from overlying sediments in the hydrostatically pressured section, indicating that the underpressure system is sealed. The study indicates that the depression has undergone rapid deposition in a rift period during the Cretaceous followed by a long‐term slow uplift and erosion in the Tertiary. On the basis of the modelled results of the abnormal pressure evolution in a typical cross‐section using a two‐dimensional numerical flow model, we believe that the predecessor of the underpressure system was an overpressure system. Since the end of the Cretaceous, the observed underpressure system has developed as a result of a geotemperature decrease ranging from 30 to 70 °C, owing to palaeoheat flow reduction and long‐term uplift and erosional cooling. The mudstones below a depth of 1550 m in the deep subnormal pressure system have small measured porosities ranging from 4% to 1.2% with calculated permeability of about 10?21–10?24 m2. The observed underpressure can be modelled if we assign permeabilities below 10?20 m2 with a linear reduction of geotemperature. The geotemperature decrease, in combination with very low permeability in the Lower Cretaceous mudstones, is therefore a possible origin for the formation of the underpressure system in this depression. 相似文献