铀在高岭土上的吸附动力学及热力学研究

采用静态法研究了铀(U(Ⅵ))在高岭土上的吸附特性,探讨了pH、离子强度、接触时间、温度、腐殖酸等对U(Ⅵ)在高岭土上吸附的影响.以宏观吸附实验为基础,对高岭土进行X线衍射(XRD)和扫描电镜(SEM)表征,并讨论了铀(U(Ⅵ))在高岭土上的吸附动力学及热力学行为.结果说明,准二级动力学模型可以用来描述铀在高岭土上的吸附.通过对溶液pH值和离子强度因素的研究,溶液pH值对铀的吸附影响比离子强度对铀的吸附影响更大.在较低pH值下,腐殖酸对吸附有加强的作用;在较高pH值下,腐殖酸对吸附有抑制作用.Freundlich模型可较好地描述高岭土对U(Ⅵ)的吸附过程.高岭土对U(Ⅵ)的吸附为自发且吸热的过程,主要是表面单分子层吸附.     

H2O2对铁负载膨润土吸附铀(VI)影响的试验研究

系统研究了过氧化氢(H2O2)影响铁负载膨润土吸附铀(Ⅵ)的效果与机理.通过改变pH、H2O2浓度、初始U(Ⅵ)浓度,探讨了加入H2O2的条件下铁负载膨润土对U(Ⅵ)的吸附过程,并采用扫描电镜(SEM)、红外光谱(FT-IR)等对吸附U(Ⅵ)前后的铁负载膨润土进行了表征.试验结果表明,溶液初始pH为3～6时,H2O2能使铁负载膨润土对U(Ⅵ)的吸附率达到98%以上;H2O2浓度对反应平衡时的吸附性能影响不大;随着U(Ⅵ)浓度的增大,H2O2对铁负载膨润土吸附U(Ⅵ)的促进作用也随之增强,U(Ⅵ)浓度为0.64 mmol/L时,吸附量从1.74 mmol/g(铁负载膨润土)增至3.13 mmol/g(H2O2和铁负载膨润土的复合体系).     

回生淀粉吸附U(Ⅵ)的特性及机理分析

以玉米淀粉(CS)为原材料,采用加热后冷藏溶剂交换法制备回生淀粉(MS)。通过静态吸附实验,考察了初始pH、投加量、铀初始浓度及温度等因素对MS吸附U(Ⅵ)的影响。试验结果表明,pH值6为最佳pH值,在温度25℃条件下,MS对10mg/LU(Ⅵ)溶液去除率可达97.8%。反应过程符合准二级动力学方程与Langmuir热力学方程。FT-IR、SEM和EDS分析结果表明,MS吸附铀前后表面形态发生了改变,MS吸附U(Ⅵ)的机理为表面络合吸附,起主要作用的是表面活性羟基。     

微生物腐败物对U(Ⅵ)的吸附动力学与热力学研究

为了解微生物腐败物对U(Ⅵ)的作用,通过扩大培养微生物,令其自然死亡腐败,制备了微生物腐败物.通过静态实验,对不同pH、反应时间、温度和铀初始质量浓度对微生物腐败物吸附铀的影响进行了研究,并进行了动力学和热力学分析.结果表明,pH、反应温度和铀初始质量浓度均是影响吸附的重要因素,吸附量随着铀初始质量浓度的增加而增加,反...     

粘土岩对铀(Ⅵ)的吸附特征研究

以内蒙古阿拉善粘土岩为研究对象,通过静态吸附实验,探讨接触时间、U(Ⅵ)初始浓度、固液比、pH值、离子类型以及离子浓度等因素对U(Ⅵ)吸附特征的影响.研究结果表明:粘土岩对U(Ⅵ)的吸附速率较快,24h即可达到吸附平衡,最佳吸附固液比为1∶200,最佳吸附初始浓度为160μg·mL-1;随着pH值的增大,粘土岩对U(Ⅵ)的吸附能力不断增强,pH为8时,吸附能力达到最大;溶液中Ca~(2+)、CO_3~(2-)和HCO_3~-对U(Ⅵ)吸附有很强的抑制作用,不利于U(Ⅵ)的吸附,K~+、Na~+、Cl~-、NO_3~-、SO_4~(2-)对U(Ⅵ)的吸附影响较弱,U(Ⅵ)在粘土岩表面吸附主要以内层络合作用为主.因此,开展粘土岩对U(Ⅵ)的吸附研究,对我国高放废物的处置工作开展起到了极其关键的作用.     

磁性MOFs复合材料(Fe3O4@HKUST-1)的制备及其对U(VI)的吸附研究

以Fe_3O_4磁性纳米粒子、Cu(NO3)2·3H2O和均苯三甲酸为主要原料合成了一种新型磁性MOFs复合材料-Fe_3O_4@HKUST-1,对其进行XPS、SEM、XRD以及FT-IR表征分析,结果显示该复合材料形貌结构是以Fe_3O_4磁性纳米粒子为核,HKUST-1将其包裹在内.以Fe_3O_4@HKUST-1作为吸附剂,研究不同环境条件下(pH、浓度和吸附时间)对铀的吸附影响.在pH为4的条件下,铀在Fe_3O_4@HKUST-1上有较高的吸附量.Fe_3O_4@HKUST-1对U(Ⅵ)的吸附符合二级动力学模型以及Langmuir等温吸附模型.研究结果表明,Fe_3O_4@HKUST-1对水中U(Ⅵ)有着良好的吸附能力,可作为一种高效的铀吸附材料.     

纳米赤铁矿吸附剂吸附低浓度U(Ⅵ)的行为与机理

采用水热法制备了纳米赤铁矿吸附剂,对不同pH值、吸附剂用量、吸附时间和初始U(Ⅵ)浓度下纳米赤铁矿吸附剂吸附低浓度U(Ⅵ)的行为进行了研究,并采用XRD、SEM和EDS对纳米赤铁矿吸附剂吸附U(Ⅵ)前后的表面形貌进行了表征和分析,揭示了纳米赤铁矿吸附剂吸附低浓度U(Ⅵ)的动力学特征和吸附机理。结果表明,当温度为25℃、pH为7、吸附剂用量为0.4 g/L、U(Ⅵ)的初始质量浓度为5mg/L时,在120 min时吸附即达到了平衡;此时,吸附率最高,达到了92. 62%;纳米赤铁矿吸附剂吸附低浓度U(Ⅵ)的过程是一个快速平衡的过程,其动力学过程符合准二级动力学模型,说明纳米赤铁矿吸附低浓度U(Ⅵ)的方式主要为化学吸附,其吸附等温线符合Freundlich吸附模型,表明纳米赤铁矿吸附低浓度U(Ⅵ)为多层吸附。     

腐殖质还原菌去除U(Ⅵ)的试验研究

试验探讨了腐殖质还原菌去除U(Ⅵ)的特性与效果,重点考察了温度、pH、AQS、U(Ⅵ)浓度等因素对腐殖质还原菌去除U(Ⅵ)的影响.试验结果表明,腐殖质还原菌对低浓度U(Ⅵ)有很好的去除效果,其去除U(Ⅵ)的最适温度为30℃左右,最佳pH在6.0左右,AQS的最佳用量约为1.0 mmol/L.红外光谱分析表明,羧基、酰胺基和磷酸基团是腐殖质还原菌除铀过程中占主导地位的官能团.     

腐殖酸钛盐对铀(Ⅵ)的吸附动力学与热力学研究

为了了解腐殖酸钛盐对铀在土壤中迁移的影响,本研究通过一系列静态吸附实验,开展了在不同pH、接触时间、温度和初始铀质量浓度等条件下,腐殖酸钛盐对铀(Ⅵ)的吸附研究,并进行了动力学和热力学分析。实验结果表明溶液pH值和初始铀质量浓度是影响腐殖酸钛盐吸附铀(Ⅵ)的重要因素,吸附量随着初始铀质量浓度的增加而增大,且在pH=6时吸附效果最佳,吸附量为34. 75 mg/g,吸附平衡时间约为90 min。腐殖酸钛盐对铀的吸附动力学符合准二级动力学模型,即吸附主要是化学吸附。吸附热力学研究发现腐殖酸钛盐对铀的吸附符合Freundlich模型,表明吸附是多层吸附;腐殖酸钛盐对铀的吸附是一个自发的吸热过程,即温度升高有利于吸附作用。     

微生物腐败物对U(VI)的吸附动力学与热力学研究

为了解微生物腐败物对U(VI)的作用,通过扩大培养微生物,令其自然死亡腐败,制备了微生物腐败物。通过静态实验,对不同pH、反应时间、温度和铀初始质量浓度对微生物腐败物吸附铀的影响进行了研究,并进行了动力学和热力学分析。结果表明,pH、反应温度和铀初始质量浓度均是影响吸附的重要因素,吸附量随着铀初始质量浓度的增加而增加,反应在pH=4,温度为30 ℃时吸附效果最佳,吸附量为11.922 mg/g,吸附平衡时间为90 min。微生物腐败物对U(VI)的吸附动力学符合准一级动力学模型,表明吸附过程以物理吸附为主。吸附热力学研究发现其对U(VI)吸附过程符合Freundlich等温线模型,表明吸附作用过程主要为从外层扩散到内层的多层吸附。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with