乙二胺硅胶材料对铜和锌离子的动态吸附

合成了胺基含量为1.35 mmol/g的乙二胺硅胶材料(EDA/SiO2),研究了EDA/SiO2对Cu2+和Zn2+的动态吸附及动态竞争吸附。结果表明,铜溶液流量和初始浓度对材料动态吸附性能有显著影响,随着溶液初始浓度的增大、流速的加快,穿透时间明显缩短。动态吸附实验结果符合Thomas模型,计算结果显示,铜溶液初始浓度由1.99 mmol/L增大至10.00 mmol/L时,模型平衡吸附容量q0从0.272 mmol/g增大至0.476 mmol/g,影响显著;流量对q0影响不显著。溶液流量和初始浓度对吸附速率常数kTh均有影响,随溶液流量增大、初始浓度的降低,速率常数值增大。在单一体系中,EDA/SiO2对Cu2+和Zn2+的工作吸附量分别为0.340和0.127 mmol/g,混合体系的吸附量均小于单一体系中的吸附量,并且对Zn2+的吸附量下降显著,表明EDA/SiO2对Cu2+的吸附能力强于Zn2+。6次循环实验表明,盐酸和氨水可对EDA/SiO2材料实现再生,再生后材料对铜的吸附容量和穿透时间的下降幅度不大,可重复使用。     

乙二胺硅胶复合材料对Zn2+的吸附特性

以γ-氯丙基三氯硅烷为偶联剂,将乙二胺偶合接枝在硅胶表面,合成对锌离子具有吸附作用的乙二胺硅胶复合材料（EDA/SiO2）,考察了Zn2+溶液pH值、初始浓度、吸附温度和吸附时间等因素对复合材料吸附性能的影响。 结果表明,在研究的溶液浓度及温度范围内,Zn2+溶液pH值对EDA/SiO2的吸附量影响显著,吸附的最佳pH值范围在3.0~5.5;Zn2+的吸附平衡数据符合Langmuir吸附模型,热力学数据显示,EDA/SiO2对Zn2+的吸附行为为一吸热且自发进行的过程,升高温度有利于吸附,并对此吸附行为作了解释;吸附动力学数据可用拟二级吸附动力学方程描述,得到的吸附速率常数与溶液初始浓度有关。     

Adsorption of Metallocenes on Silica

The adsorption of the metallocenes ferrocene, doubly deuterated ferrocene, cymantrene and nickelocene, as well as molybdenum hexacarbonyl, proceeds in the absence of a solvent. Large single pieces of silica gel were placed in contact with the solid metallocenes and the adsorption process was visualized on a macroscopic scale and the maximal loadings were determined. ¹H, ²H, and ¹³C solid‐state NMR studies confirmed fast isotropic reorientation of the surface‐adsorbed metallocene molecules within the pores of the silica. All prevalent anisotropic solid‐state interactions were averaged out. The solid diamagnetic and paramagnetic materials were amenable to measurements with a standard solution NMR instrument. All metallocenes adsorbed in a monolayer. In the case of ferrocene and cymantrene, different ¹³C MAS signals were obtained for the cyclopentadienyl ring carbon nuclei and assigned to one ring interacting with the surface and one ring pointing away from it. The relative adsorption strengths of ferrocene on different silica supports, nanotubes, and activated carbon were determined by a novel straightforward method recording the desorption temperature. The reversibility of adsorption has been demonstrated by competition experiments using ferrocene, doubly deuterated ferrocene, and cymantrene. Adsorbed nickelocene could be reduced to small Ni⁰ aggregates on the surface and the catalytic activity of the resulting material for the cyclotrimerization of phenylacetylene was proven.     

Surface Modification of Porous Silica with Bi-thiophene Tripodal Ligand and Aplication to Adsorption of Toxic Metal Cations

The immobilization of a thiophene-based tripodal ligand, with a donor sulfur, on the surface of an epoxide group containing a silica gel phase for the synthesis of a newly functionalized material based on porous silica-bound bi-thiophene tripodal ligand (SGBT) is described. The modified silica surface was characterized by ¹³C NMR of a solid sample, elemental analysis, and infrared spectra. This new material was also studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and BJH pore sizes, respectively. The target material exhibits good thermal stability as determined by thermogravimetry curves. The synthesized material was utilized in column and batch methods for adsorption of Hg²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Zn²⁺, K⁺, Na⁺, and Li⁺, and the material exhibits an affinity only towards toxic heavy metals.     

Adsorption of Cationic Surfactants on Highly Dispersed Silica

Comparative study was made of adsorption of cationic surfactants, decamethoxine, ethonium, and cetyltrimethylammonium bromide, on a highly dispersed amorphous silica at different pH values. Contrary to the adsorption of monoquaternary ammonium compound, cetyltrimethylammonium bromide, the adsorption of bis(quaternary ammonium) compounds, ethonium and decamethoxine, was found to be caused mainly by electrostatic interaction. The adsorption of antiseptic decamethoxine is reversible at pH 6; this may be used to design carriers capable of controlled drug release into the surrounding medium.     

Chromatographic Behavior of 43 Cations on Silica Gel G in Acetone-Formic Acid Systems

Abstract

A systematic study of the chromatographic behavior or 43 metal ions has been carried out in Acetone-Formic Acid systems on thin layers of Silical Gel G. The separation potential of these systems has been investigated for numerous metal ions and a number of useful and interesting separations have been predicted. The results obtained have been discussed and analysed.     

Ethyleneimine Anchored on Thiol-Modified Silica Gel Surface-Adsorption of Divalent Cations and Calorimetric Data

Activated silica gel was previously modified by the silylant agent 3-mercaptopropyltrimethoxysilane. The organofunctionalized silica gel containing pendant groups ended with the -SH functions reacted with the three-member cyclic ethyleneimine molecules to yield the new ligand attaching sulfur and nitrogen basic centers available to complex cations. This final anchored surface adsorbs MX(2) (M=Co(2+), Ni(2+), Cu(2+), and X=Cl(-), NO(3)(-)) at 298+/-1 K. A considerable increase in adsorption capacity was observed for nitrate counteranions. This process of extraction was followed by the batch method and the order of the maximum capacities found was Ni(2+)>Cu(2+)>Co(2+) for both series of salts. The pendant immobilized groups-cation interaction processes showed exothermic enthalpies. Those values are more pronounced for chlorides, with the largest values obtained for cobalt. The calculated DeltaG values are in agreement with the spontaneity of the proposed reactions and the complexation is entropically favored. Copyright 2000 Academic Press.     

Microcalorimetric Study of Methanol Adsorption on Initial Silica and Silica Modified with Polyfluoroalkyl Groups

The adsorption of methanol on initial silica and modified silica samples containing large mesopores is studied by the adsorption–calorimetric method. The grafted tridecylfluoroalkyl groups have a tilted orientation on the silica and physically screen the part of the surface OH groups that have not been involved in the reaction with a modifier. Adsorbed methanol makes the modifying layer looser, thus facilitating the accessibility of methanol molecules to these hydrophilic adsorption sites. Concentrations of OH groups involved in the chemical interaction with molecules of the modifier, OH groups physically screened by its organofluoric radicals, and OH groups located on the surface areas free of the modifier are quantitatively estimated. An additional silanization of the modified silica leads to coverage of silica surface areas that are free of organofluoric modifier with trimethylsilyl radicals. The heat of interaction between the methanol molecules and silica surface hydroxyl groups is determined; it is equal to 60 kJ/mol. The structure of the modifying organofluoric layer and changes in this structure that resulted from additional silanization of the surface and from the methanol adsorption are discussed.     

Influence of Ring Structures on Optical Properties of Trivalent Bismuth in Bi-Doped Silica Optical Fiber

We report silica fiber with trivalent bismuth (Bi³⁺) in first-principles calculations. The influences of members of “Si–O–Si” rings are considered to study atomic structures, frontier molecular orbital and optical properties of Bi-doped optical fiber. Our results reveal that the luminescence of Bi³⁺-doped optical fiber is the result of a combination of Bi³⁺ ions and silica matrix. Different ring structures affect the luminescence properties, which explained why Bi³⁺-doped silica fiber usually cover a broad spectral range from the UV to visible light.     

层板金属离子不同的钴基双氢氧化物制备及其电化学性能

通过调变层板中的三价金属离子制备了层板金属离子不同的钴基双氢氧化物(LDHs),X-射线衍射(XRD)和傅里叶变换红外(FTIR)测试表明,层板中金属离子的变化对LDHs的物理结构有较大影响。电化学性能比较表明,三价金属离子的改变对材料的有效工作电位窗口和大电流稳定性及循环容量保持率均有很大影响。由于二价与三价金属离子在电化学过程中的作用不同,Co-AlLDHs在1A·g-1的电流密度下比容量达到447F·g-1;Co-InLDHs与Co-CrLDHs则具有很好的循环稳定性和电容性质。     

聚丙烯酰胺在硅胶表面上的吸附及其抑制的研究

聚丙烯酰胺(PAM)具有强极性,对硅胶等极性固体表面具有强烈的吸附作用,陈九顺等用4％的NaCl水溶液为淋洗液和Adamson用0.1mol/L的吗啡啉水溶液为淋洗液虽能部分解决硅胶担体对PAM样品的吸附,但他们对吸附的实质问题未进行研究,PAM等高分子化合物在固体表面上的吸附问题的研究尚处于初级阶段。     

超疏水有机-无机杂化硅基介孔分子筛对苯丙氨酸的吸附研究

为了提高中性氨基酸在硅基介孔分子筛上的吸附量, 采用中性氨基酸苯丙氨酸(Phe)为模型吸附质, 考察Phe在一种新型的通过非模板剂途径制备的有机-无机杂化硅基介孔分子筛上的吸附情况. 利用该分子筛超疏水表面、大的比表面积和孔容以及特殊的疏水区域, Phe达到了非常突出的吸附效果. 通过优化溶剂组成, 发现当溶剂为等体积比的甲醇和水的混合溶液时, Phe在此分子筛上的最大吸附量达到0.827 mmol/L, 远高于同等条件下Phe在常规法制备的甲基化硅基介孔分子筛上的吸附量0.122 mmol/L. 对Phe在该分子筛上的吸附机制进行了简要阐述.     

阳离子型聚氨酯-脲-胺在二氧化硅水溶胶听吸咐行为

研究了水溶性阳离子聚氨酯-脲-胺乙酸盐在球形、单分散的纳米二氧化硅水分 散注保的吸附行为。PUUA分子链在烯溶液中呈较舒展的构象，分子尺寸小于纳米氧 化硅的粒径。PUUA通过van der Waals作用力和氢键吸附在氧化硅表面。在稳喧吸 附后，等温吸附线呈线性上升，且没有极限值。吸附量随纳米氧化硅粒径的增大、 胶粒表面电荷的减少和电解质乙酸钢加入量的变化均以相同的斜率线性下降。 PUUA分子量增加，吸附量增加，且分子量大的PUUA优先吸附于氧化硅胶粒表面，静 电吸引是PUUA吸附至氧化硅溶胶粒表面的主要作用力。PUUA在氧化硅胶粒上的吸咐 使体系表现粘度下降，敏化作用使体系呈假塑性，而保护作用使体系呈胀流型。     

铁离子在多齿配体功能化硅胶上的吸附研究

以自制的多齿配体功能化硅胶为吸附剂,探究了配体齿数对废水中常见重金属离子吸附的影响.研究结果表明,五齿配体亚氨基二琥珀酸-硅胶吸附剂对铁离子(Fe3+)的吸附能力最强,吸附量为14.4 mg/g.进一步探讨了此吸附剂对Fe3+的吸附动力学和热力学行为,考察了Fe3+浓度、温度、转速以及共存离子对吸附的影响,并对吸附剂的...     

Adsorption of Polyelectrolyte-Nanoparticle Systems on Silica: Influence on Interaction Forces

In this work, we have studied the interfacial properties of cationic polyelectrolyte (PE) and silica nanoparticle (NP) systems at macroscopic silica surfaces by means of ellipsometry. The influence of adsorbed layers on the interactions between silica surfaces was also investigated using the bimorph surface force apparatus. Added nanoparticles were observed to strongly swell the interfacial polyelectrolyte layers, an effect partly related to neutralization of charged polyelectrolyte groups. The effect was more pronounced for low charged than for highly charged polyelectrolytes. Overall, the presence of nanoparticles seemed to increase the repulsive interaction measured between silica surfaces. The force measured on approach was long range and quite strongly repulsive. On separation, an attractive bridging interaction was measured for polyelectrolyte-covered surfaces. For the low charged polyelectrolyte used in the study, the force turned repulsive on addition of nanoparticles. For the highly charged polyelectrolyte used, a change from a very strong attraction (involving a jump of the surfaces out of contact) to a very long-range elastic attractive force was observed on adding nanoparticles. The long-range elastic force indicates that polymer chains and nanoparticles form a transient network in the gap between the surfaces. The observed difference in the outward force curves may explain why the addition of nanoparticles appears to improve, e.g., shear-resistance and reflocculation characteristics of polymeric flocculants. Copyright 2000 Academic Press.     

Adsorption of Cationic Surfactants on Silica Surface: 1. Adsorption Isotherms and Surface Charge

Adsorption isotherms of cationic surfactant, dodecylpyridinium chloride, on an Aerosil OX50 and isotherms of surface charge against the background of 0.001- and 0.1-M KCl solutions at pH 7 and 9 were measured and analyzed. Different forms of adsorption isotherms of surfactants at low and high electrolyte concentrations are explained from differences in the formation of the surface charge of Aerosil. Comparison of the isotherms of surfactant adsorption and surface charge allowed us to make conclusions about the surfactant orientation and structure of an adsorption layer, as well as to determine the fraction of surfactant molecules in the first and second adsorption layers.     

Effect of Co-Existing Cations and Anions on the Adsorption of Antibiotics on Iron-Containing Minerals

The adsorption of antibiotics on minerals is an important process in their environment behavior. The adsorption behavior of antibiotics on iron-containing minerals and the effect of co-existing cations and anions were studied in this work. Magnetite, hematite, goethite and kaolin were selected as the representative minerals and characterized by SEM, XRD and BET. A total of eight antibiotics, including three quinolones, three sulfonamides and two mycins were chosen as the research targets. Results showed a higher adsorption amount of quinolones than that of sulfonamides and mycins on the surface of iron-containing minerals in most mineral systems. The adsorption isotherms of quinolones can be well fitted using the Freundlich models. The effects of five cations and five anions on the adsorption of quinolones were investigated, among which Mg²⁺, Ca²⁺, HCO₃⁻ and H₂PO₄⁻ mainly showed significant inhibition on the adsorption, while the effects of K⁺, Na⁺, NH₄⁺, Cl⁻, NO₃⁻ and SO₄²⁻ showed less. Natural surface water samples were also collected and used as media to investigate the adsorption behavior of quinolones on iron-containing minerals. The buffering capacity of the natural water kept the reaction solution at circumneutral conditions, and the adsorption amount was mostly promoted in the goethite system (from 0.56~0.78 μmol/g to 0.52~1.43 μmol/g), but was inhibited in the other systems (magnetite: from 1.13~1.33 μmol/g to 0.45~0.76 μmol/g; hematite: from 0.52~0.65 μmol/g to 0.02~0.18 μmol/g; kaolin: from 1.98~1.99 μmol/g to 0.90~1.40 μmol/g). The results in this work help to further understand the transportation and fate of antibiotics in an aqueous environment.     

有序介孔二氧化硅对正丁醛的吸附性能

合成了一系列具有不同孔结构与性质的有序介孔二氧化硅材料SBA-15、MCM-41、SBA-16、KIT-6, 同时通过改变水热温度制备了不同孔径大小的SBA-15, 并利用小角X射线散射、透射电镜、扫描电镜和氮气吸附-脱附等手段, 对其介孔结构进行了表征. 以正丁醛为探针分子, 考察了其对有机醛的吸附, 并与Y-沸石的吸附性能做了对比. 结果表明, 材料的介孔比表面积与其对正丁醛的吸附量成正比, 吸附等温线符合Langmuir 模型, 属于单层吸附, 具有最大介孔比表面积的MCM-41对正丁醛的吸附量最大(484 mg·g^-1). 最后将SBA-15添加到卷烟滤嘴中, 实验结果表明, SBA-15能显著降低卷烟烟气中巴豆醛的释放量.     

有序介孔二氧化硅对正丁醛的吸附性能

合成了一系列具有不同孔结构与性质的有序介孔二氧化硅材料SBA-15、MCM-41、SBA-16、KIT-6,同时通过改变水热温度制备了不同孔径大小的SBA-15,并利用小角X射线散射、透射电镜、扫描电镜和氮气吸附-脱附等手段,对其介孔结构进行了表征.以正丁醛为探针分子,考察了其对有机醛的吸附,并与Y-沸石的吸附性能做了对比.结果表明,材料的介孔比表面积与其对正丁醛的吸附量成正比,吸附等温线符合Langmuir模型,属于单层吸附,具有最大介孔比表面积的MCM-41对正丁醛的吸附量最大(484 mg·g-1).最后将SBA-15添加到卷烟滤嘴中,实验结果表明,SBA-15能显著降低卷烟烟气中巴豆醛的释放量.