改性纤维素吸附剂对重金属离子的吸收

纤维素中含有许多亲水性的羟基基团,通过羟基的衍生化反应,可以将其制备成重金属离子的吸附剂。本文首先介绍了改性纤维素吸附剂制备的原料、步骤,接着阐述了改性纤维素吸附重金属离子的机理,最后探讨了影响改性纤维素吸附的一些因素。     

羧甲基马铃薯渣对水溶液中铅离子吸附性能的优化

为了更有效解决重金属铅离子对水资源污染的严重问题,对羧甲基马铃薯淀粉渣吸附铅离子的性能进行优化研究.以马铃薯淀粉渣为原料,通过醚化改性工艺,制备了羧甲基化马铃薯淀粉渣吸附剂.在单因素试验的基础上,采用Box-Benhnken的中心组合试验设计及响应面分析法,研究了吸附剂用量、吸附时间和pH值三因素对水溶液中铅离子吸附效...     

改性纤维素吸附剂的制备及其对重金属离子的吸附

纤维素中含有许多亲水性的羟基基团，通过羟基的衍生化反应，可以将其制备成重金属离子的吸附剂。本文首先介绍了改性纤维素吸附刺制备的原料、步骤，接着阐述了改性纤维素吸附重金属离子的机理，最后探讨了影响改性纤维素吸附的一些因素。     

活性污泥吸附重金属离子的研究

重金属废水的污染日益严重,寻找廉价高效的吸附剂是经济地处理重金属废水的关键.试验选择活性污泥为吸附剂,考察其对重金属离子Cu2+、Zn2+和Cd2+的吸附性能.实验结果表明,活性污泥对3种重金属离子都有很强的吸附能力,且吸附很快,前4 min时的去除率和吸附量上升最快;在常温范围内,温度对活性污泥吸附金属的影响并不显著,而体系pH值和吸附剂投加量的影响较为重要;活性污泥对3种重金属离子的吸附均符合Langmuir模型.     

吸附去除水体重金属离子的影响因素研究进展

为了深入研究吸附法去除重金属离子过程中的影响因素,文中系统地阐述了温度、pH值、吸附剂用量、共存离子、共存有机物等因素对吸附过程的影响,这些影响与吸附剂、目标金属离子的性质,以及吸附过程所涉及的吸附机制有关。阐明水体中重金属离子吸附过程中的影响规律以及产生这种影响的机理,不仅有助于吸附机理的确定,还能以此评价吸附剂的实际应用性能。吸附剂的选择是探讨其他影响因素的前提,其物理性质影响到暴露的活性吸附位点数量和吸附质的传质扩散过程,化学性质不仅影响吸附剂的吸附容量和吸附平衡时间,还决定了吸附剂的吸附选择性能;溶液温度的影响与吸附的热力学性质有关;溶液pH值会改变吸附剂活性位点的化学状态和重金属离子在水中的赋存形态;不同的溶液初始浓度提供了不同的驱动力;更多的吸附剂提供更多的吸附位点,但吸附剂过多可能发生团聚现象,反而影响吸附效果;共存离子对吸附过程的影响与背景离子的种类和浓度相关。文中总结了各种因素对水体中重金属离子吸附过程影响的规律以及产生这种影响的机理,以期为水体中重金属离子污染的吸附去除和水体净化提供一定的理论依据。     

改性红辉沸石对重金属离子铅的吸附性能研究

本文研究了产于广西资源县车田乡的红辉沸石对重金属离子铅的吸附性能,考察了铅离子溶液的pH值、温度、吸附时间、吸附剂用量等因素对吸附率的影响。实验研究初步得出红辉沸石对铅离子的最佳吸附条件为:25℃,pH=5.0~6.0即弱酸条件,吸附时间为2.5h,当铅离子浓度为100 mg/L,沸石投加量为1.0g,其吸附率为92%~93.5%;用H2SO4改性沸石后对铅离子的吸附率和吸附容量影响有较大提高,平均吸附容量达2.271mg/g,经过再生实验结果仍然具有较高的吸附率。     

活性污泥对重金属离子的吸附研究

采用活性污泥为吸附剂,对3种重金属离子Cd^2＋、Zn^2＋和Cd^2＋进行吸附．结果表明,活性污泥对重金属离子吸附很快,前4min时的去除率和吸附量上升最快;常温范围内,温度对活性污泥吸附金属的影响并不显著,而体系PH值和吸附剂投加量的影响较为重要,活性污泥对3种重金属离子的吸附都符合Langmuir模型．     

碱活化-煅烧制备生物炭对重金属的吸附研究

为探究碱活化-煅烧生物炭对水中重金属的吸附性能,采用氢氧化钠活化-管式炉煅烧制备柚子皮生物炭,通过吸附水中铅离子的试验研究。结果表明:碱活化-煅烧后柚子皮粉在扫描电镜下呈片状结构,表面平整,结构有序,杂质明显减少,内部有丰富的孔道,为后续吸附反应提供了充足的条件;红外光谱分析得知羧基、羟基类基团起到主要的吸附作用;pH、震荡时间、吸附剂用量、重金属铅离子的初始浓度和震荡温度等因素,都对碱活化-煅烧生物炭吸附水中重金属铅离子有显著的影响。通过实验,得出用5%氢氧化钠改性并经过管式炉煅烧后的改性柚子皮粉对重金属铅离子的去除率可达到98%以上。分别用Langmuir和Freundlich对吸附等温方程进行拟合,未经煅烧的柚子皮粉吸附废水中重金属铅离子吸附等温线更符合Freundlich等温方程,经煅烧的柚子皮粉生物炭吸附废水中重金属铅离子的吸附等温线更符合Langmuir吸附等温方程。     

NaOH改性珍珠岩对重金属离子的吸附研究

以珍珠岩为吸附剂,经NaOH溶液改性后,进行Cd~(2+)、Cu~(2+)和Zn~(2+)的吸附实验,研究吸附剂碱改性对重金属离子的吸附性能.结果表明,碱改性后珍珠岩对Cd~(2+)、Cu~(2+)和Zn~(2+)的吸附去除率明显高于未改性的珍珠岩.在重金属离子溶液初始质量浓度为100 mg/L时,改性珍珠岩对Cd~(2+)、Cu~(2+)和Zn~(2+)的吸附率分别为54.15%,96.34%和48.69%;未改性珍珠岩对Cd~(2+)、Cu~(2+)和Zn~(2+)的吸附率分别为18.41%、29.31%和15.98%.碱改性吸附剂对3种重金属离子的吸附,以对Cu~(2+)的去除最佳,吸附去除容量大小为Cu~(2+)Zn~(2+)Cd~(2+).     

氢氧化钠溶液回流法改性粉煤灰及其在镉离子吸附上的应用

用氢氧化钠溶液回流法改性粉煤灰,并用改性过的粉煤灰对一种常见的重金属离子-镉离子进行了吸附研究。在改性条件上对所用氢氧化钠的浓度,回流时间这两个因素进行了研究。在吸附过程中对吸附剂用量,吸附时间这两个因素进行了研究。实验表明:氢氧化钠浓度为4mol/L,回流时间为7h的碱改性粉煤灰对镉离子的吸附效果最佳。最佳吸附条件是:投加量为4g/L,吸附时间120min,此时Cd(Ⅱ)的去除率可达99%以上。用氢氧化钠溶液回流法改性粉煤灰可以达到以废治废的目的,改性后的产物对重金属离子吸附效率高,是一种有前景的处理重金属离子的方法。     

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.     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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