海藻酸-壳聚糖-海藻酸离子取代凝胶离子的取代性能

研究了海藻酸 壳聚糖 海藻酸 (alginate chitosan alginate ,ACA)离子取代凝胶对二价离子的取代性能。与传统离子交换树脂比较 ,ACA的离子取代速率比传统离子交换树脂快得多。ACA对二价金属离子的取代顺序是 :Pb2 + >Cu2 + >Ca2 + ≈Zn2 + ,其中 ,对Pb2 + 的选择性要大大高于Ca2 + ,其选择性系数是 316。ACA离子取代凝胶具有较快的离子取代速率和较高的吸附选择性 ,这使它有望成为一种新型的血液吸附剂用于临床金属中毒治疗。     

微囊化海藻酸离子移变凝胶的制备、结构与性能

通过静电脉冲技术制备了海藻酸-壳聚糖-海藻酸(Alginate-Chitosan-Alginate,ACA)微胶囊,红外光谱分析表明,ACA是一种以聚电解质配合物为囊膜,以海藻酸钠离子吸附剂为囊心物的微胶囊型离子吸附体系.扫描电镜测试表明,ACA吸附重金属离子的过程是微胶囊囊内海藻酸凝胶化的过程,其解吸附过程是海藻酸凝胶转变成海藻酸溶液的过程.与传统离子交换树脂相比,ACA对Pb²⁺的吸附具有较高的去除率、很强的富集能力和较低的极限吸附浓度,并且能够被多次重复使用.ACA的离子交换速率比传统离子交换树脂快得多,离子交换过程中,交换离子和吸附剂海藻酸分子的相互扩散大大提高了离子交换速率.     

海藻酸-壳聚糖-海藻酸离子取代凝胶改性研究

羧甲基壳聚糖;微胶囊;海藻酸-壳聚糖-海藻酸离子取代凝胶改性研究     

阳离子诱导海藻酸水溶液凝胶化的临界行为与自相似性

以作者对阳离子诱导海藻酸水溶液凝胶化的研究结果为中心,介绍了海藻酸钠水溶液随浓度增大和二价金属阳离子(Ca2 、Cu2 )的加入而发生的溶液-凝胶转变的临界点和相关临界指数,探讨了临界凝胶的自相似性和分形结构,以及动态标度理论对物理交联体系的适用性.基于对阳离子诱导海藻酸水溶液凝胶化及其临界行为的研究结果,提出了从凝胶化的出发点--溶液来对凝胶化进行分类的设想,根据起始组分分子链的长短将凝胶化过程分为生长型和交联型两类.     

高分子电解质溶胶—凝胶相转移与溶剂效应

以溶质、溶剂间的协同作用作为高分子电解质体系的凝胶化条件，以松软粒子结构（Ｂｏｌｂ）间的三维逾渗的凝胶化模型，将高分子电解质体系的凝胶化分为松软粒子的形成和逾渗过程。结合海藻酸溶液的Ｃｕ＾２＋、Ｃａ＾２＋、Ｍｎ＾２＋和Ｃｏ＾２＋离子添加体系的凝胶化，分析了高分子电解质溶胶－凝胶相转移的实质，得到了体系相对粘度的临界指数ｋ＝－０．９０￣１．１４，与逾渗模型的预测值相吻合，探讨了松粒子的形成对相转移介     

用动态光散射跟踪钙-海藻酸水溶液凝胶化

海藻酸(alginate)是一种天然多糖,是直链键合的β-D-甘露糖醛酸(M)和α-L-古洛糖醛酸(G)的无规嵌段共聚物[1].在海藻酸水溶液中加入钙、铜、锌、铅等二价正离子,能够形成凝胶;其中钙-海藻酸凝胶在细胞输送、组织工程等领域受到人们的关注[2,3].影响海藻酸凝胶化的因素包括海藻酸的分子量和分子量分布、M/G值和序列分布、溶液浓度、正离子种类与浓度等[4,5].     

一种制备勃姆石溶胶的新方法

以氯化铝为起始原料经离子交换过程制备勃姆石溶胶.该方法将阴离子交换树脂加入三氯化铝溶液中,提供OH-离子的同时可同步去除等量Cl-离子.应用TEM对溶胶胶粒结构进行了研究,采用XRD、FTIR对不同条件下制备的凝胶结构进行了分析,对制备勃姆石溶胶过程中的影响因素进行了探讨.结果表明,老化时间和溶液中Cl-离子浓度对产物的结构和性能有显着影响,Cl一离子完全去除后经老化可以获得稳定的勃姆石溶胶.等温氮气吸附结果显示,r氧化铝的比表面积随着老化时间的延长而下降.老化4h和16h后得到γ-氧化铝的比表面积分别为223.12m2/g和176.86m2/g.     

高分子电解质溶胶－凝胶相转移与溶剂效应

以溶质、溶剂间的协同作用作为高分子电解质体系的凝胶化条件，以松软粒子结构（Ｂｌｏｂ）间的三维逾渗的凝胶化模型，将高分子电解质体系的凝胶化分为松软粒子的形成和逾渗过程。结合海藻酸溶液的Ｃｕ２＋、Ｃａ２＋、Ｍｎ２＋和Ｃｏ２＋离子添加体系的凝胶化，分析了高分子电解质溶胶－凝胶相转移的实质，得到了体系相对粘度的临界指数ｋ＝０．９０～１．１４，与逾渗模型的预测值相吻合，探讨了松软粒子的形成对相转移临界点ｆｃ的影响，明确了临界点附近相对粘度的幂次公式ηｒｅｌ∝（ｆｃ—ｆ）－ｋ）的适用范围。     

溶胶-凝胶法合成Li_4SiO_4

Li4SiO4具有有利于离子传导的结构,为锂离子导体理想的基质材料[1].在硅酸盐体系中,硅的聚合态很复杂,难以得到纯相,鉴于固相法操作简单,在已有的文献中,合成方法多为固相法,但固相法不易保证成份的准确性、均匀性且合成温度较高.溶胶-凝胶法是近几年来发展起来的湿化学合成方法,用此法合成离子导体具有纯度高、均匀性好、颗粒小、反应过程易于控制等优点[2],而通常的溶胶-凝胶法是用金属醇盐与有机盐为前驱物,这样成本较高,且易造成污染.本文用金属醇盐及无机盐为前驱物,用溶胶-凝胶法合成了Li4SiO4纯相,并同一般固相法相比较,对合成的…     

海藻酸钠与钙或锌离子凝胶动力学过程研究

测定了海藻酸钠与锌或钙离子交联的凝胶动力学过程，利用线性模型(LAM)对凝胶过程进行了模拟．实验结果表明，钙或锌离子的初始反应速率方程分别为：dCCa/d(t)[mol^-1s^-1]=0.000109C^0.796与dCZn/d(t)[mol^-1s^-1]=0.0000405C^0.317；利用线性模型(LAM)可较好的拟合凝胶全过程；LAM模型计算结果表明，随凝胶离子浓度增加，凝胶离子表观扩散系数增加，凝胶速率加快，完全凝胶时间缩短：在相似的凝胶离子浓度下，钙离子的表观扩散系数大于锌离子的表观扩散系数，表明海藻酸锌完全凝胶时间较长，这与实际凝胶过程相符，主要是锌离子凝胶体系的刚性较强及锌离子半径相对较大造成的。     

Preparation, Properties and Mechanism of Inhomogeneous Calcium Alginate Ion Cross-linking Gel Microspheres

Inhomogeneous calcium alginate ion cross-linking gel microspheres,a novel ion absorbent,were prepared by dropping a sodium alginate solution to a calcium chloride solutioin via an electronic droplet generator.Calcium alginate microspheres have uniform particle sizes.a smooth surface and a microporous structure.The electrode probe reveals the inhomogeneous distribution of calcium ions with the highest concentration on the surface,and the lowest concentration in the cores of the spheres.As a novel ion adsorbent,calcium alginate gel microspheres have a lower limiting adsorption mass concentration,a higher enrichment capacity and a higher adsorption capacity for Pb^2 than usual ion exchange resins.The highest percentage of the adsorption is 99.79%.The limiting adsorption mass concentration is 0.0426mg/L.The adsorption capacity for Pb^2 is 644mg/g,Calcium alginate gel microspheres have a much faster ion exchange velocity than D418 chelating resin and D113 polyacrylate resin.The moving boundary model was employed to interpret the ion exchange kinetics process,which indicates that the ion exchange process is controlled by intraparticle diffusion of adsorbable ions.So the formation of inhomogeneous gel microspheres reduces the diffusion distance of adsorbable ions within the spheres and enhances the ion exchange velocity.Alginate has a higher selectivity for pb^2 than for Ca^2 and the selectivity coefficient KCa^Pb is 316. As an ion cross-linking gel,calcium alginate inhomogeneous microspheres can effectively adsorb heavy metal Pb^2 at a higher selectivity and a higher adsorption velocity.It is a novel and good ion adsorbent.     

Alginate hydrogels as biomaterials

[Image: see text] Alginate hydrogels are proving to have a wide applicability as biomaterials. They have been used as scaffolds for tissue engineering, as delivery vehicles for drugs, and as model extracellular matrices for basic biological studies. These applications require tight control of a number of material properties including mechanical stiffness, swelling, degradation, cell attachment, and binding or release of bioactive molecules. Control over these properties can be achieved by chemical or physical modifications of the polysaccharide itself or the gels formed from alginate. The utility of these modified alginate gels as biomaterials has been demonstrated in a number of in vitro and in vivo studies.Micro-CT images of bone-like constructs that result from transplantation of osteoblasts on gels that degrade over a time frame of several months leading to improved bone formation.     

以铜离子为模板的褐藻酸凝胶对铜离子的选择性富集研究

以铜离子为模板，制备了褐藻酸凝胶（Cu-alginate)，通过吸附实验及过柱渗滤实验，试验了该吸附剂对铜离子的选择性吸附性能，并且采用该吸附剂富集了自来水中微量的Cu^2 ，结合原子吸收法测定了水样中Cu^2 的含量。结果表明：该吸附剂对Cu^2 有较高的选择性吸附性能，显著优于一些化学合成铜离子模板缩聚物及非铜模板褐藻酸凝胶（如Ca-alginate),非重金属离子（如K^ 、Na^ 、Ca^2 ）及某些重金属离子（如Ni^2 、Cd^2 ）等对Cu^2 的吸附均不产生明显干扰。用该吸附剂富集水中的微量铜离子，回收率可达97.7%。     

Diffusion of Acetic Acid Across Oil/Water Interface in Emulsification-Internal Gelation Process for Preparation of Alginate Gel Beads

Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules.Although an alternative novel emulsification-internal gelation technology has been established and both the properties and the potential applications of the beads in drug delivery systems have been studied,the mechanism has not been well understood compared with the traditional droplet method(external gelation technology).On the basis of our previous knowledge that the novel technology is composed of complicatedly consecutive processes with multistep diffusion and reaction,and the diffusion of acetic acid across oil/water interface being the prerequisite that determines the occurrence and rate for the reactions and the structures and properties of final produced gel beads,a special emphasis was placed on the diffusion process.With the aid of diffusion modeling and simple experimental design,the diffusion rate constant and diffusion coefficient of acetic acid across oil/water interface were determined to be in the orders of magnitude of 10-6 and 10-16,respectively.This knowledge will be of particular importance in understanding and interpreting the formation,structure of the gel beads and the relationship between the structure and properties and guiding the preparation and quality control of the gel beads.     

油田稠油污水深度处理回用热采锅炉的软化处理技术

针对油田热采直流蒸汽锅炉给水水质要求，采用离子交换法对稠油污水进行软化处理，经过对比实验，确定选用大孔弱酸阳离子交换树脂D113，投入中试运行二个月，来水平均硬度为170mg/L，出水硬度未检出，达到了蒸汽热采锅炉对进水水质硬度的要求，大孔弱酸阳离子交换树脂进行酸再生和碱转型，可以有效地抵抗有机污染负荷，实现高浓度，高水温有机污水的软化处理。     

稀土离子在多孔阳离子交换剂内的扩散动力学

研究了稀土离子在Amberlyst15、D001、XN1010多孔树脂内的自扩散。结果表明,扩散过程遵循二级分散扩散机制。用粒内扩散方程求算了有效粒内扩散系数e,将e分解为树脂孔道扩散系数p及树脂固相扩散系数s,p与该离子在外部溶液中的自扩散系数相近,而s接近于与实验用的多孔树脂交联度相同的凝胶树脂内的自扩散系数值。     

Adaptive Ion-Gel: Stimuli-Responsive,and Self-Healing Ion Gels

Ion gels are an emerging class of polymer gels in which a three-dimensional polymer network swells with an ionic liquid. Ion gels have drawn considerable attention in various fields such as energy and biotechnology owing to their excellent properties including nonvolatility, nonflammability, high ionic conductivity, and high thermal and electrochemical stability. Since the first report on ion gels (published ∼30 years ago), diverse functional ion gels exhibiting impressive physicochemical properties have been reported. In this review, recent developments in functional ion gels that can modulate their physical properties in response to environmental conditions are outlined. Stimuli-responsive ion gels that can adaptively undergo phase transitions in response to thermal and light stimuli are initially discussed, followed by an evaluation of diverse self-healing ion gels that can spontaneously mend mechanical damage through judiciously designed ion-gel networks.     

非均相聚砜螯合滤膜的制备及其对Cu~(2+)的吸附性能研究

通过探讨共混比例、螯合树脂粒径及铸膜液温度对膜结构的影响 ,确定了最佳制膜工艺 ,用相转换法制备出对Cu2 + 具有大螯合容量的非均相螯合滤膜 .研究了螯合树脂颗粒粒径、盐溶液pH值和盐溶液浓度对膜螯合吸附量的影响 ,发现膜对Cu2 + 的最大吸附量可达 70 0 μg cm2 ,吸附行为满足Freundlich吸附等温式 .对膜进行动态螯合吸附测试表明该膜对Cu2 + 可实现吸附与解吸同步进行