磁性功能化酚醛树脂的合成及对金属离子的吸附性能

磁性功能化酚醛树脂的合成及对金属离子的吸附性能;环氧酚醛树脂;螯合;金属离子;溶胀;吸附容量;吸附动力学     

硫脲树脂的合成及其对金属离子的吸附性能

采用双(异硫氰酸甲酸)丁二酯分别与二乙烯三胺、三乙烯四胺、四乙烯五胺、多乙烯多胺单体进行加聚反应制得4种主链上含有硫脲基团的新型螯合树脂PETU-Ⅰ～PETU-Ⅳ。红外光谱分析表明,树脂中存在硫脲基团,树脂热稳定性和溶胀性能良好。用静态吸附法研究了PETU树脂对金属离子的吸附性能,4种树脂对Au(Ⅲ)的吸附容量分别为2.48、2.68、4.74和6.44mmol/g,对Ag(Ⅰ)的吸附容量分别为2.15、3.53、3.74和3.98mmol/g,对Cu(Ⅱ)、Zn(Ⅱ)等金属离子吸附容量低于0.36mmol/g;PETU-Ⅳ对Au-Cu和Au-Zn的分离因子>1000,PETU-Ⅱ对Ag-Cu和Ag-Zn的分离因子>10,说明树脂对Au(Ⅲ)、Ag(Ⅰ)具有较高的吸附容量和优良的吸附选择性。PETU-Ⅳ树脂重复使用5次,吸附容量无明显下降,说明树脂具有良好的重复利用性能。     

Ion‐exchange resins. III. Functionalization–morphology correlations in the synthesis of some macroporous,strong basic anion exchangers and uranium‐sorption properties evaluation

The synthesis and characterization of a series of macroporous, strong basic anion exchangers (SBAEs), with an average pore radius higher than 50 nm, and the evaluation of their sorption properties for uranyl chlorocomplexes from HCl solutions are reported. Finely divided macroporous styrene–divinylbenzene (S–DVB) copolymers with a narrow distribution of beads sizes, diameters within the range of 90–200 μm, were prepared for this purpose with 2‐ethyl‐1‐hexanol as a porogen, at a high dilution of monomers (D ≥ 0.55 mL/mL). Chloromethyl groups were introduced with (CH₂O)_n/Me₃SiCl as a chloromethylation agent in the presence of a Lewis acid as a catalyst (TiCl₄, SnCl₄, and FeCl₃) in CHCl₃ as a reaction medium. SnCl₄ and FeCl₃ gave comparable chloromethylation degrees in the same reaction conditions. TiCl₄ was not efficient as a catalyst in the chloromethylation with this reagent. Diethyl‐2‐hydroxyethylamine was used as a tertiary amine to prepare SBAEs. Structural and morphological characteristics were determined after every functionalization step of the macroporous network. Both the chloromethylation, in the presence of FeCl₃ as a catalyst, and the amination reactions determined a significant decrease of the pore volume, in the whole range of the nominal crosslinking degree, comparative with the starting copolymer. The specific surface area and the average pore radius varied in a different way as a function of the nominal crosslinking degree. Thus, the specific surface area increased and the average pore radius decreased after chloromethylation and amination for copolymers with a DVB content lower than 10 wt %. Small decreases of the specific surface area and the average pore radius were observed after chloromethylation and amination reactions for copolymers with a DVB content higher than 10 wt %. SBAEs were also characterized by thermogravimetric analysis and sorption capacity for uranyl chlorocomplexes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2451–2461, 2004     

Water-Soluble Polyacids with Capability to Remove Metal Ions in Homogenous Phase by Using the Liquid Phase Polymer-Based Retention Technique

Water-soluble polymers containing carboxylic acid and sulfonic acid groups were investigated as polychelatogens under different experimental conditions in view to study their metal ion binding properties, using the liquid-phase polymer-based retention technique. The divalent metal ions investigated were: Co²⁺, Cu²⁺, Zn²⁺, and Cd²⁺. When the pH increased above 3, and especially at pH 5, metal ion retention capability increased as the majority of the functional groups are carboxylate, which can form more stable complexes with the metal ions. The retention capability also depended on the structure of the polyacid and the filtration factor, Z.     

Recovery of Metal Ions by Chitosan: Sorption Mechanisms and Influence of Metal Speciation

Chitosan is characterized by a high affinity for metal ions due to its high content of amine groups. The sorption mechanism depends on both the protonation of these amine groups and the speciation of metal ions. Metal cations may be adsorbed at pH close to neutrality by chelation mechanism while metal anions can be adsorbed in acidic solutions through ionic interactions with protonated amine groups. Several examples are considered. The first example focuses on Cd sorption, which proceeds by a chelation mechanism on free non‐protonated amine groups in neutral media. In acidic solutions the protonation of amine groups limits the ability of amine groups to complex Cd. The cross‐linking of chitosan with glutaraldehyde also results in a dramatic decrease of sorption properties due to the decrease in the density of complexation sites available for sorption. The sorption of vanadium(V) and molybdenum(VI) illustrates the high capacity of chitosan for the sorption of oxo‐anions. They are very efficiently sorbed in acidic solutions by ionic interactions. The correlation of sorption capacities with the distribution of metal species shows that the sorbent has a greater affinity for highly charged anionic species. The sorption of complex anionic species such as chloro‐complexes of Pd and Pt; and that of copper complexed with organic ligands have also been studied. The optimum conditions for sorption are obtained when anionic complexes predominate in the solution. The chemical modification of chitosan, obtained by grafting of sulfur compounds, allows modifying the sorption mechanism: the ion‐exchange polymer is transformed to a dual ion‐exchange and chelating polymer.

Copper sorption isotherm in presence of sodium citrate (0.004 M ) (? RNH: fraction of protonated amine groups; ACuC: total fraction of anionic copper complexes; Cu‐FAL: total fraction of copper‐free anionic ligands).     

聚氯乙烯负载席夫碱树脂的合成及其对金属离子的吸附

聚氯乙烯负载席夫碱树脂的合成及其对金属离子的吸附刘理中，俞善信，肖立新（湖南师范大学化学系长沙４１００８１）（中南工业大学冶金化学研究所长沙）关键词聚氯乙烯，负载树脂．席夫碱，金属离子，吸附高分子负载席夫碱可用于离子吸附和催化等领域，汪信［１，２］等...     

A Novel Polymeric Chemosensor: Dual Colorimetric Detection of Metal Ions Through Click Synthesis

A highly colored polystyrene derivative bearing side chain chromophores composed of dialkylanilino donor and cyano‐based acceptor groups, prepared by atom‐economic click postfunctionalization, displays the dual colorimetric detection behavior of several metal ions based on the specific interactions with different nitrogen atoms. Hard to borderline metal ions, such as Fe³⁺, Fe²⁺, and Sn²⁺, are always recognized by the dialkylanilino nitrogen atom, resulting in a decrease in the charge‐transfer (CT) band intensity of the donor–acceptor chromophores. On the other hand, the recognition site of a soft metal ion of Ag⁺ is the cyano nitrogen atom due to the readily formed multivalent coordination, which produces a bathochromic shift of the CT band.     

阳离子交换色谱中色谱柱温度对碱金属与碱土金属离子保留的影响

研究了非抑制型阳离子交换色谱中色谱柱温度(25~50℃)对碱金属离子(Li+、Na+、K+、Rb+)和碱土金属离子(Mg2+、Ca2+、Sr2+)以及NH4+保留的影响。在Shim-pack IC-C1磺酸型阳离子交换柱上,以硝酸为流动相分离碱金属离子,以乙二胺或乙二胺-草酸(柠檬酸)为流动相分离碱土金属离子,随着色谱柱温度的升高,碱金属和碱土金属离子的保留时间均增长,其范特霍夫曲线具有良好的线性关系,斜率为负值,表明在此条件下碱金属和碱土金属离子的保留为吸热过程。在Shim-pack IC-SC1羧酸型阳离子交换柱上,以硫酸为流动相同时分离碱金属和碱土金属离子,随着色谱柱温度的升高,Mg2+、Ca2+的保留时间增长,而K+、Rb+的保留时间缩短,Li+、Na+、NH4+的保留时间基本不变。在此条件下,Mg2+、Ca2+、K+和Rb+的范特霍夫曲线具有良好的线性关系,其中Mg2+和Ca2+的曲线斜率为负值,K+和Rb+的曲线斜率为正值,表明Mg2+和Ca2+的保留表现为吸热过程,K+和Rb+的保留表现为放热过程。研究表明在不同固定相和流动相条件下,色谱柱温度对碱金属和碱土金属离子保留行为的影响不同。     

Application of Ion Exchange Techniques to Industrial Process of Metal Ions Removal From Wine

In this article, the application of selective ion exchange resins to the industrial metals removal of wine has been studied as an alternative to the "blue clarification" technique. In this sense, under the perspective of using this technology in the metals removal of sherry wines, a set of experiments at laboratory and pilot plant scale have been carried out. The study shows the behavior of several alkaline ions, metal ions and other parameters (pH, colour, protein index, etc.) during the process. Moreover, using the general theoretical model for continuous multistage processes, this study contemplates also the engineering design and the economic balance of the industrial process based on ion exchange columns. The experimental results demonstrates that ion exchange techniques are more effective and economic than "blue clarification" for metals removal of sherry wines. The proposed practice does not produce alterations in the qualities of the products; it achieves stability enough and also permits an important decrease of the contents of heavy metals.     

Retention of Some Metal Ions and Their Separation on Silica Gel Modified with Acid Red 88

 Acid Red 88 is strongly extracted by chloroform solutions of Aliquat 336 by an ion exchange mechanism and for its reextraction from the ion pair formed, relatively high concentrations of mineral acids are required. By impregnation of silica with the ion pairs between the cation of Aliquat 336 and the anion of the dye a chelating sorbent for metal ions can be obtained. The sorbent prepared may be successfully used for separation of mixtures of various metal ions by the column extraction chromatography technique, additional purification of sodium and potassium salts from ions of heavy metals and for concentration of trace amounts of ions of various metals from aqueous solutions followed by their quantitative determination. The sorbent can be used repeatedly in the process of sorption and desorption of metal ions (especially those forming less stable complexes with the reagent) after regeneration with solutions of perchloric acid. Received January 28, 1998. Revision March 1, 1999.     

Sorption of Some Metal Ions on Inorganic Electron and Ion Exchangers Based on Zirconium(IV)

Conditions of sorption of nonferrous metal ions on inorganic electron and ion exchangers based on zirconium(IV) were analyzed. The sorption capacity was evaluated as influenced by pH, concentration, and temperature of the contacting solutions and nature and chemical composition of the ion exchanger.     

Synthesis and Characterization of Mesoporous Titanosilicate as an Adsorbent for Toxic Metal Ions

Hexagonal mesoporous titanosilicates (Ti‐MCM‐41) have been prepared using cetyltrimethylammonium bromide (CTAB) as the structure directing agent under the mild alkaline conditions. Powder X‐ray diffraction, nitrogen gas sorption, FTIR spectroscopy and thermogravimetry analysis of samples have confirmed that well ordered MCM‐41 type mesoporous materials were prepared. The potential of removing toxic metal ions from waste waters using mesoporous titanosilicates was evaluated. Separation of Co^II‐U^VI, Cs^I‐U^VI and Sm^III‐U^VI has been developed on columns of this adsorbent.     

Ion Exchange Behavior of Cadmium, Mercury, Silver and Zinc on Retardion 11A8 and Chelex 100 Ion Exchangers in Ammonia Medium and Its Application for Radiochemical Separations

The ion exchange behavior of cadmium, zinc, mercury and silver in ammonia medium on Retardion 11A8 and Chelex 100 resins containing weakly acidic cation exchange groups of complexing properties has been investigated. The results revealed that apart from a simple replacement of counter-ions, sorption of these elements is accompanied by complex formation with the functional groups of the ion exchanger. The general quantitative relationship between the mass distribution coefficient of a given metal (_Me) and concentration of ammonia (C _NH3) has been derived. If a complex formation reaction in the stationary phase occurs, _Me decreases with the increase of C _NH3. The absolute value of the slope of the dependence log_Me–log[NH₃] corresponds to the average number of ammonia molecules displaced by the functional groups from the coordination sphere of the central ion. Examples of the use of Retardion 11A8 as well as Chelex 100 for the separation of trace amounts of Cd, Zn, Hg and Ag are presented.     

有机硅修饰的剥层水滑石及其对废水中金属离子的吸附

对剥层的镁铝硝酸根水滑石(Mg2Al-NO3-LDHs)片表面进行了有机硅化合物(N-(2-Aminoethyl)-3-aminopropyl)tris-(2-ethoxy)silane(KH-791)修饰,并研究了修饰后的水滑石片对废水中Pb2+,Cu2+和Zn2+离子的吸附行为。结果表明:在相同的温度和金属离子浓度条件下,被修饰的水滑石片对Pb2+吸附容量最大,达到378.0 mg.g-1;在以上几种金属离子的混合溶液中,修饰主体材料表现出对Pb2+高度的选择性吸附,对Pb2+吸附容量为85 mg.g-1,而对Zn2+和Cu2+的吸附容量只有30 mg.g-1左右。     

稀土离子的高效毛细管电泳分离和测定

以咪唑为背影为电解质，以乳酸作为络合剂，采用毛细管离子电泳间接紫外法，研究了分离与测定稀土离子的方法，考察了背景电解质酸度、络合剂浓度，背景电解质共存离子的浓度，分离电压对稀土离子的影响。     

功能化MOFs及MOFs/聚合物复合膜在有机染料和重金属离子吸附分离中的应用

全球工业的发展带来了严重的水污染问题,对含各类有机和无机污染物工业废水的处理也成为了重要研究课题。金属-有机骨架(Metal-Organic Frameworks, MOFs)化合物由于其大比表面积、高孔隙率、有序孔道结构及可调节孔道物理化学性质、热稳定性高、易于合成和丰富的开放活性位点等特点,在诸多领域得到广泛应用,其中在固相吸附/分离领域,特别是吸附水中污染物方面展现出良好应用前景。通过合成后改性、使用含取代基配体原位合成、与特定功能材料复合等方法实现MOFs功能化,可有效增加MOFs材料的吸附活性位点,提高吸附性能和吸附选择性。与MOFs颗粒相比较,MOFs/聚合物复合膜结合了MOFs颗粒的结构与物理化学特性以及聚合物薄膜优秀的分离/载体性能,在有机染料及重金属离子的吸附中表现出优秀的吸附/分离性能。本文重点综述了以染料和重金属离子为代表的有机、无机污染物的吸附去除为目标的MOFs功能化方法,以及MOFs/聚合物复合膜的制备方法,并对未来研究方向和研究前景进行展望。     

Chelex100螯合树脂与某些金属离子的发光行为及其分析应用

作者观察到Ｅｕ＾３＋、Ｔｂ＾３＋、Ｇｄ＾３＋、Ａｌ＾３＋、Ｇａ＾３＋、Ｉｎ＾３＋、Ｚｒ＾４＋和Ｈｆ＾４＋的二元络合物在水溶液中能够与ＥＤＴＡ型的螯合树脂ｃｈｅｌｅｘ１００形成配位体－金属离子－ｃｈｅｌｅｘ１００的三元络合物，络合物的形成不但改变了它们的光谱性质，而且大大增强了其磷光或荧光强度。利用这一性质，本文制作了测定上述金属离子的流通式光学传感器。实验表明该传感器提高了测定的灵敏度与选择性。     

Organosilicon ion‐exchange and complexing adsorbents

Literature data concerning research organosilicon ion‐exchangers and complexing agents have been summarized and systematized. Data on organophilic organosilicon adsorbents and sorption systems for chromatography are not considered here. Copyright © 1999 John Wiley & Sons, Ltd.     

有机酸在阴离子交换树脂上的保留行为及其机理

研究了有机酸在阴离子交换树脂上的保留行为。首次报道了有机酸在阴离子交换色谱过程中的“多峰现象”,即一种有机酸有两个或两个以上的色谱峰流出色谱柱。对这种“多峰现象”形成的机理进行了初步探讨,提出了有机酸离解后的不同价数阴离子在阴离子交换树脂上同时保留的机理。研究中还发现离解很弱的有机酸的保留行为不完全符合离子交换机理。     

辐射诱导合成水凝胶及其处理重金属废水的研究进展*

水凝胶是一种经适度交联而具有三维网络结构的新型功能高分子材料。制备水凝胶因操作简单、无须添加交联剂和引发剂等优点而受到关注。传统的处理重金属废水的方法或成本较高,或效率低,利用水凝胶处理重金属废水成为一种新的颇具潜力的方法。本文综述了辐射法制备水凝胶及其在重金属吸附去除方面的研究进展包括材料的制备、改性、去除重金属性能等方面的研究进展,并指出了水凝胶去除重金属的发展前景和今后的研究方向。