海藻酸-壳聚糖-海藻酸凝胶离子取代机理

研究了海藻酸-壳聚糖-海藻酸(ACA)凝胶的离子取代机理.光学显微镜照相法证实ACA离子取代过程中溶胶-凝胶相界面的存在.动边界模型描述ACA离子取代凝胶对二价离子的取代动力学过程,结果表明,模型可靠.离子取代凝胶对二价离子的取代属于颗粒扩散控制机理.与离子交换树脂比较,ACA离子取代速率要快得多,ACA离子取代过程不同于传统离子交换树脂离子交换过程,它是金属离子在溶胶凝胶相转移过程中的取代过程;ACA是一种崭新的离子移变凝胶型离子吸附剂.     

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。     

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     

电导法研究树脂与游离酸的相互作用

利用电导实验技术跟踪树脂吸附游离酸的行为 ,讨论了外加盐和乙醇等因素对吸附的影响 ,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 ,树脂吸附游离酸 ,其表观吸附速率常数随着外加盐离子浓度的增大而减少 ;表观吸附速率常数与吸附剂 -吸附质相互作用能存在线性关系。     

不同反离子类型D354树脂吸附游离酸性能研究

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。     

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].     

载细胞海藻酸钠/壳聚糖微胶囊的化学破囊方法研究

以海藻酸钠-壳聚糖-海藻酸钠微胶囊(简称ACA微胶囊)为研究体系,建立了一种生理条件下ACA微胶囊的化学破囊方法,破囊过程充分考虑了对囊内生物物质活性的保持.以微生物细胞PichiapastorisGS115和动物细胞L929为模型,以NaHCO₃和Na₃C₆H5O₇·2H₂O为破囊液基本组分,考察了破囊液对ACA微胶囊的破囊效果及破囊过程对囊内细胞活性的影响.结果表明,破囊操作可在30s内完成,破囊率为100%,微胶囊膜完全溶解,破囊后细胞存活率在85%以上.     

聚离子液体水凝胶用于中性水中Cr(VI)的去除

随着经济的快速发展,水污染已成为全球关注的紧迫问题。其中,Cr（VI）在废水中含量较高且毒性较强,可引起多种严重疾病。而大多数污染地表水和地下水的pH往往是接近中性的。因此,开发具有近中性pH值下有效去除Cr（VI）的吸附剂对生态系统和公众健康至关重要。本文设计并制备了具有不同结构的三氮唑鎓聚离子液体水凝胶,并将其应用于CrO42-的吸附和释放。该水凝胶可在中性条件下实现水中CrO42-的100%去除,最大吸附量高达356 mg/g。等温吸附结果表明,在较低浓度下CrO42-在聚离子液体水凝胶中为单层吸附。此外,可进一步通过离子交换将吸附于水凝胶中的CrO42-释放出来,实现吸附剂的再生。     

低浓度下离子交换树脂吸附氨基酸的机理

详细地研究了在低浓度下, 酸(碱)式或盐式强酸性阳离子和强碱性阴离子交换树脂吸附氨基酸的机理·结果表明, 氨基酸通过离子交换、离子转移和物理吸附等三种机理被离子交换树脂吸附。     

电化法研究壳聚糖树脂与游离酸的相互作用

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。     

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.     

Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater.     

巯基树脂对重金属离子的吸附性能

研究了自合成的巯基树脂对重金属离子Pb^2 、Cu^2 、Cd^2 ．Ni^2 、Co^2 的吸附容量、吸附动力学、等温吸附过程等静态吸附性能，同时研究了影响吸附的因素和吸附机理．结果表明，该树脂对软酸型重金属离子吸附容量高．pH=5．0-5．7，低温有利于吸附，树脂对各重金属离子等温吸附在实验浓度范围内均符合Langmuir和Freundnch方程．吸附机理研究表明，巯基与重金属离子发生了离子交换和配位反应，化学吸附起支配作用。     

微胶囊膜表面化学组成的XPS分析

采用XPS表面表征技术对生物微胶囊膜表面化学组成进行了分析。结果表明,海藻酸钠_壳聚糖_海藻酸钠(ACA)微胶囊表面带负电荷的含C基团与带正电荷的含N基团的相对百分含量分别为30·6%与60·4%,而海藻酸钠_聚赖氨酸_海藻酸钠(APA)微胶囊分别为42·3%与30·0%,因此ACA微胶囊表面比APA微胶囊带更多的正电荷,更有利于蛋白质吸附与细胞粘附。为深入了解生物微胶囊表面引起的机体反应过程、改进微胶囊性能,提供了理论依据。     

Adsorption of Cu(II), Zn(II), Ni(II), Pb(II), and Cd(II) from aqueous solution on Amberlite IR-120 synthetic resin

The adsorption of copper(II), zinc(II), nickel(II), lead(II), and cadmium(II) on Amberlite IR-120 synthetic sulfonated resin has been studied at different pH and temperatures by batch process. The effects of parameters such as amount of resin, resin contact time, pH, and temperature on the ion exchange separation have been investigated. For the determination of the adsorption behavior of the resin, the adsorption isotherms of metal ions have also been studied. The concentrations of metal ions have been measured by batch techniques and with AAS analysis. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Freundlich isotherms. Here we report the method that is applied for the sorption/separation of some toxic metals from their solutions.     

Industrial wastes as low-cost potential adsorbents for the treatment of wastewater laden with heavy metals

Industrial wastes, such as, fly ash, blast furnace slag and sludge, black liquor lignin, red mud, and waste slurry, etc. are currently being investigated as potential adsorbents for the removal of the heavy metals from wastewater. It was found that modified industrial wastes showed higher adsorption capacity. The application of low-cost adsorbents obtained from the industrial wastes as a replacement for costly conventional methods of removing heavy metal ions from wastewater has been reviewed. The adsorption mechanism, influencing factors, favorable conditions, and competitive ions etc. on the adsorption of heavy metals have also been discussed in this article. From the review, it is evident that certain industrial waste materials have demonstrated high removal capacities for the heavy metals laden with wastewater. However, it is to be mentioned that adsorption capacities of the adsorbents vary depending on the characteristics of the adsorbents, the extent of chemical modification and the concentration of adsorbates. There are also few issues and drawbacks on the utilization of industrial wastes as low-cost adsorbents that have been addressed. In order to find out the practical utilization of industrial waste as low-cost adsorbents on the commercial scale, more research should be conducted in this direction.     

Kinetic,mechanism and equilibrium studies on removal of Pb(II) using <Emphasis Type="Italic">Citrus limettioides</Emphasis> peel and seed carbon

The sorption behaviour of Pb(II) ions onto activated carbon prepared from Citrus limettioides peel (CLPC) and seed (CLSC), which is a novel waste material, was evaluated as a function of contact time, pH, adsorbent dose, ionic strength, initial metal ion concentration and temperature in batch adsorption processes with raw Citrus limettioides peel (CLP) and seed (CLS). The maximum uptake of lead(II) ions was obtained at pH range 4.0–6.0 for CLPC, CLSC and 5.0–6.0 for raw materials (CLP, CLS). The optimal contact time was found to be 3 h. Surface morphology and functionality of the adsorbent were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and Fourier-transform infrared (FT-IR) spectroscopy. The equilibrium data fit well with the Langmuir isotherm, confirming monolayer coverage of lead(II) ions onto CLP, CLPC, CLS and CLSC. The Langmuir monolayer adsorption capacity of CLP, CLPC, CLS and CLSC was found to be 123.60, 166.67, 15.32 and 142.86 mg/g. The calculated thermodynamic parameters showed that the sorption process was feasible, spontaneous and exothermic in nature. Kinetic studies demonstrated that adsorption of lead(II) ions followed a pseudo-second-order equation, suggesting that the adsorption process is presumably chemisorption. The adsorbents were tested for removal of Pb(II) from electroplating wastewater in connection with the reuse and selectivity of the adsorbents.     

Chitosan-g-MPEG-modified alginate/chitosan hydrogel microcapsules: a quantitative study of the effect of polymer architecture on the resistance to protein adsorption

The chemical modification of the alginate/chitosan/alginate (ACA) hydrogel microcapsule with methoxy poly(ethylene glycol) (MPEG) was investigated to reduce nonspecific protein adsorption and improve biocompatibility in vivo. The graft copolymer chitosan-g-MPEG (CS-g-MPEG) was synthesized, and then alginate/chitosan/alginate/CS-g-MPEG (ACAC(PEG)) multilayer hydrogel microcapsules were fabricated by the layer-by-layer (LBL) polyelectrolyte self-assembly method. A quantitative study of the modification was carried out by the gel permeation chromatography (GPC) technique, and protein adsorption on the modified microcapsules was also investigated. The results showed that the apparent graft density of the MPEG side chain on the microcapsules decreased with increases in the degree of substitution (DS) and the MPEG chain length. During the binding process, the apparent graft density of CS-g-MPEG showed rapid growth-plateau-rapid growth behavior. CS-g-MPEG was not only bound to the surface but also penetrated a certain depth into the microcapsule membranes. The copolymers that penetrated the microcapsules made a smaller contribution to protein repulsion than did the copolymers on the surfaces of the microcapsules. The protein repulsion ability decreased with the increase in DS from 7 to 29% with the same chain length of MPEG 2K. CS-g-MPEG with MPEG 2K was more effective at protein repulsion than CS-g-MPEG with MPEG 550, having a similar DS below 20%. In this study, the microcapsules modified with CS-g-MPEG2K-DS7% had the lowest IgG adsorption of 3.0 ± 0.6 μg/cm(2), a reduction of 61% compared to that on the chitosan surface.