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1.
电化法研究壳聚糖树脂与游离酸的相互作用   总被引:12,自引:1,他引:12  
利用电化实验技术,跟踪观察交联壳聚糖树脂吸附低浓度游离酸的行为,讨论了酸和甲醇浓度等因素对吸附的影响,利用固-液相互作用方程,求取吸附剂一吸附质相互作用能。实验结果表明,交联壳聚糖树脂吸附低浓度游离酸的过程是遵循单分子层机制进行的,表观吸附速率常数随着吸附质浓度和外加甲醇含量的增大而减小,表观吸附速率常数与吸附剂一吸附质相互作用能(U)存在线性相关。  相似文献   

2.
外加盐对壳聚糖树脂吸附游离酸的影响   总被引:5,自引:0,他引:5  
利用电化实验技术,跟踪观察交联壳聚糖树脂在不同环境体系吸附低浓度游离酸的行为。讨论了在三元体系(酸 水 盐)和四元体系(酸 水 有机物 盐)中,交联壳聚糖树脂吸附游离酸的规律。利用固-液相互作用方程,求取吸附剂-吸附质相互作用能。实验结果表明,交联壳聚糖树脂在三元体系和四元体系中吸附游离酸,表观吸附速率常数(k)随着外加盐浓度的增大而减小。发现表观吸附速率常数(k)与吸附剂-吸附质相互作用能(U)存在线性关系。  相似文献   

3.
利用吸附质-分子探针-电导法,研究吸附过程的特性,讨论不同类型反离子的变形性和离子势对D354树脂吸附游离酸的影响。根据固-液相互作用方程求取吸附剂-吸附质相互作用能(U),实验结果表明,D354树脂吸附低浓度游离酸的过程遵循单分子层机理。吸附剂-吸附质相互作用能制约表观吸附速率常数(k),k、U两者存在线性相关性。  相似文献   

4.
制备了SO42-、NO3-、ClO4-和F-、Cl-、Br-、I-两种新型阴离子苯乙烯-二乙烯苯聚合物微球,基于吸附质-分子探针电导法,研究了阴离子聚合物吸附低浓度游离酸的性能,考察了阴离子类型和温度对吸附行为的影响。实验结果表明,在30℃时,吸附游离酸的过程,遵循单分子层机理进行吸附。吸附剂-吸附质相互作用能U制约表观吸附速率常数K,两者存在线性相关性,K、U均随阴离子的离子势增大呈逐渐减小的趋势。吸附过程为吸热的,吸附焓变ΔH为10.87 kJ.mol-1。吸附过程谱维数ds增大,导致表观吸附速率常数降低。吸附质对吸附剂的亲和能Ua随吸附质-吸附剂相互作用参数K2增大而减小。  相似文献   

5.
流动注射分光光度法研究壳聚糖树脂吸附阴离子染料   总被引:5,自引:0,他引:5  
利用流动注射分光光度法技术,跟踪观察交联壳聚糖树脂吸附阴离子染料的行为,讨论了外加氯化钠或甲醇以及温度等因素对吸附的影响。利用固-液相互作用方程,求取了吸附剂-吸附质相互作用能。实验结果表明,交联壳聚糖树脂吸附 子染料,其表观吸附速率常数随体系中氯化钠浓度或甲醇含量的增大而减小,随温度的升高而增大;交联壳聚糖树脂吸附酸性铬蓝K染料的表观活化能力26.095kJ/mol。  相似文献   

6.
利用电导实验技术跟踪弱碱性阴离子树脂吸附低浓度游离酸的行为 ,研究了外加盐和醇等介质对吸附的影响。实验结果表明 ,弱碱性阴离子树脂吸附低浓度游离酸 ,其吸附速率随外加盐和醇的增加而减小  相似文献   

7.
氨基膦酸螯合树脂吸附重稀土的研究   总被引:3,自引:0,他引:3  
研究了重稀土在氨基膦酸树脂的吸附行为.试验结果表明,氨基膦酸树脂对重稀土的吸附在pH=5.0的HAc-NaAc缓冲溶液时最佳;298K时静态饱和吸附容量为332mg/g干树脂;用2mol/L盐酸洗脱,洗脱率为91.2%;等温吸附服从Freundlich经验式;吸附反应中△H=10.76kJ/mol,表观速率常数k298=1.223×10-4s-1,表观活化能Ea=3.2kJ/mol.  相似文献   

8.
研究了AH系列胺基修饰的超高交联树脂对水溶液中间苯二酚的静态吸附行为特征,结果表明,它们对间苯二酚的吸附容量明显高于母体交联树脂NDA-100和大孔弱碱性阴离子交换树脂D301.AH系列树脂与吸附质分子之间不仅有范德华作用力,还存在着氢键等作用力.该类树脂对间苯二酚的吸附为自发的放热过程,属于以物理作用为主兼有弱化学作用的吸附过程.吸附速率符合准一级动力学方程,表观吸附速率常数随树脂胺基含量的升高而降低.  相似文献   

9.
氨基膦酸树脂对钕(Ⅲ)的吸附性能   总被引:1,自引:0,他引:1  
研究了氨基膦酸树脂对钕(Ⅲ)的吸附行为。当pH=5.70时,氨基膦酸树脂对钕(Ⅲ)的静态饱和吸附容量为199.74 mg/g,用1moL/L HCl溶液可以定量洗脱,当T=298 K时,表观吸附速率常数为1.68×10~(-4)s~(-1),吸附热力学参数△H=60.68 kJ/mol,△G=-14.91 kJ/mol,△S=253.65 J/(mol·K),等温吸附服从Freundlich曲线,氨基膦酸树脂功能基与钕(Ⅲ)的配位比为2:1。用红外光谱探讨了氨基膦酸树脂与钕(Ⅲ)的成键情况。  相似文献   

10.
氨基膦酸树脂对汞的吸附性能及其机理   总被引:11,自引:0,他引:11  
研究了Hg2+在氨基膦酸树脂上的吸附行为。结果表明:静态饱和吸附容量为 581.9mg/g树脂,用0.5mol/L的HCl和0.2~0.3mol/L的EDTA洗脱,洗脱率分别为:97%和99%以上;测得吸附热力学参数分别为: △H=8.45kJ/mol,△G=-3.02kJ/mol,△S= 38.5J/mol稫。等温吸附服从Freundlich经验式;表观活化能Ea=13.6kJ/mol,表观速率常数k298=2.46×10-5/s;树脂功能基与Hg2+的配位比为1∶1;并用化学和红外光谱的方法探讨了树脂对Hg2+的吸附机理。  相似文献   

11.
利用流动注射分光光度法技术,考察了不同离子强度(NaCl)下,在水溶液中表面带负电的活性炭分别吸附3种阴离子染料的动力学行为.利用固-液相互作用方程,求取了活性炭-染料相互作用能.比较了无机盐中阳离子的种类对吸附影响的差异.结果表明:对于3种阴离子染料,离子强度的增大都起到加速吸附的作用:表现吸附速率常数、活性炭-染料相互作用能与离子强度三者之间存在密切的内在联系:在相同离子强度下,二价阳离子对吸附的加速作用要比一价阳离子的显著,但在同价阳离子之间这种作用的差别较小.  相似文献   

12.
The adsorption of free acid of low concentration by crosslinked chitosan resin was followed by electrochemical experimental technique.The effect of acid concentration and the media on adsorption was discussed.The experimental results show that both the apparent rate constant and the interaction energy between the adsorbent and adsorbate are decreased while the concentration of hydrochloric acid is increased.In the adsorption system.the adsorption was effected by addiiton of organic solvent.  相似文献   

13.
A theory has been developed for the adsorption of polyelectrolytes on charged interfaces from an aqueous salt solution. This adsorption is determined by the electrical charge density of the polyelectrolyte, the adsorption energy, the salt concentration, the molecular weight, solubility, flexibility, and concentration of polymer. The theory relates these parameters to the properties of the adsorbed polymer layer, i.e., the amount of polymer adsorbed, the fraction of the adsorbent interface covered, the fraction of the segments actually adsorbed on the interface versus the fraction of the segments in the dangling loops, the final surface charge density, and the thickness of the adsorbed layer. As polyelectrolyte adsorption should resemble nonionic polymer adsorption at high ionic strength of the solution or low charge density on the polymer, this work is an extension of the nonionic polymer adsorption theory to polyelectrolyte adsorption. The following effects are taken into account: (a) the conformational change upon adsorption of a coil in solution into a sequence of adsorbed trains interconnected by loops dangling in solution; (b) the interactions of the adsorbed trains with the interface and with each other; (c) the interaction of the dangling loops with the solvent; (d) the change in surface charge density of the adsorbent due to adsorption of charged trains and the accompanying changes in the electrical double layer which contains “small” ions as well as charged loops; (e) the (induced) dipole interaction of the adsorbed trains with the charged adsorbent interface. The theory is worked out for low potentials (Debye—Hückel approximation); in Appendix B an outline of a more complete treatment is given. The predicted adsorption isotherms have the experimentally observed high-affinity character. A relation between the adsorption energy, the surface charge density on the adsorbent, the degree of dissociation of the polymer, and the salt concentration predicts the conditions under which no adsorption will occur. For adsorbent and polymer carrying the same type of charge (both positive or both negative) the adsorption is predicted to decrease with increased charge density on polymer or adsorbent and to increase with salt concentration. If adsorbent and polymer carry different type charges, the adsorption as a function of the degree of dissociation, α, goes through a maximum at a relatively low value of α and, depending on the adsorption energy, an increase in the salt concentration can then increase or decrease the adsorption. At finite polymer concentration in solution the number of adsorbed segments and the fraction of the interface covered practically do not change with an increase in polymer concentration, whereas the total number of polymer molecules adsorbed increases slightly, as does the average fraction of segments in loops. The experimental results for polyelectrolyte adsorption have been reviewed in general and, as far as data are available, the predictions of the theory seem to follow the experimentally observed trends quite closely, except for the thickness of the adsorbed layer. This thickness is systematically overestimated by the theory and two reasons for this are given. The theoretical model implies a not too low ionic strength of the solution. Extrapolation of results to solutions of very low ionic strength is not warranted.  相似文献   

14.
盐对C8-卵磷脂胶团溶液相分离的作用   总被引:3,自引:0,他引:3  
借助描述胶团溶液相变过程的唯象理论,结合有关电解质作用的理论模型,分析了盐对C8-卵磷脂胶团相分离的作用,导出加盐后C8-卵磷脂胶团溶液的吉布斯自由能,并据此推导出该溶液相谱临界温度随盐度类型和离子强度变化的规律,以及溶液中盐离子与卵磷肥分子相互作用的机制。  相似文献   

15.
Application of two complementary AFM measurements, force vs separation and adhesion force, reveals the combined effects of cation size and charge (valency) on the interaction between silica surfaces in three 1:1, three 2:1, and three 3:1 metal chloride aqueous solutions of different concentrations. The interaction between the silica surfaces in 1:1 and 2:1 salt solutions is fully accounted for by ion-independent van der Waals (vdW) attraction and electric double-layer repulsion modified by cation specific adsorption to the silica surfaces. The deduced ranking of mono- and divalent cation adsorption capacity (adsorbability) to silica, Mg(2+) < Ca(2+) < Na(+) < Sr(2+) < K(+) < Cs(+), follows cation bare size as well as cation solvation energy but does not correlate with hydrated ionic radius or with volume or surface ionic charge density. In the presence of 3:1 salts, the coarse phenomenology of the force between the silica surfaces as a function of salt concentration resembles that in 1:1 and 2:1 electrolytes. Nevertheless, two fundamental differences should be noticed. First, the attraction between the silica surfaces is too large to be attributed solely to vdW force, hence implying an additional attraction mechanism or gross modification of the conventional vdW attraction. Second, neutralization of the silica surfaces occurs at trivalent cation concentrations that are 3 orders of magnitude smaller than those characterizing surface neutralization by mono- and divalent cations. Consequently, when trivalent cations are added to our cation adsorbability series the correlation with bare ion size breaks down abruptly. The strong adsorbability of trivalent cations to silica contrasts straightforward expectations based on ranking of the cationic solvation energies, thus suggesting a different adsorption mechanism which is inoperative or weak for mono- and divalent cations.  相似文献   

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