CHEMICAL MODIFICATION OF THE SURFACE OF CALCIUM ALGINATE GEL BEADS

The chemical modification of the surface of calcium alginate gel beads (CAGB) via grafting copolymerization with vinyl acetate (VAc) was studied. The optimum reaction conditions with activation and graft copolymerization two steps were explored. First, 5 grams CAGB with 2.5 mm initial diameter was initiated with 0.0493 mol/L K2S2O8 at 51 °C for 30 min in 15 mL 1 % PVA/H2O. Then 4.34 moi/L VAc was added dropwise and the reaction was allowed to proce at 48 °C for 3 h. The grafting efficiency could come up to 30%. It was found the stability of modified CAGB in the air and in electrolyte solutions was greatly improved.

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.

Preparation and Characterization of AlginateHyaluronic Acid-chitosan based Composite Gel Beads

The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid（HA） and Chitosan（CS） were successfully admixed with Ca^2＋/alginate（SA） gel system to produce SA/HA/CS gel beads by dual crosslinking： the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA（2%, m/v） to HA（2%, m/v） was kept at 2：1, then the mixture was dripped into the Ca^2＋ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS（LMW-CS） for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca^2＋ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.

Two kinds of ketoprofen enteric gel beads(CA and CS-SA) using biopolymer alginate

To obtain expected rapid-release and sustained-release of ketoprofen gel beads, this paper adopted biopolymer alginate to prepare alginate beads and chitosan-alginate gel beads. Formulation factors were investigated and optimized by the single factor test. The release of ketoprofen from calcium alginate gel beads in pH 1.0 hydrochloric acid solution was less than 10% during 2 h, then in pH6.8 was about 95% during 45 min, which met the requirements of rapid-release preparations. However, the drug release of chitosan-alginate gel beads in pH1.0 was less than 5% during 2 h, then in pH6.8 was about 50% during 6 h and reached more than 95% during 12 h, which had a good sustained-release behavior. In addition, the release kinetics of keteprofen from the calcium alginate gel beads fitted well with the Korsmeyer–Peppas model and followed a case-II transport mechanism. However, the release of keteprofen from the chitosan-alginate gel beads exhibited a non-Fickian mechanism and based on the mixed mechanisms of diffusion and polymer relaxation from chitosanalginate beads. In a word, alginate gel beads of ketoprofen were instant analgesic, while chitosan-alginate gel beads could control the release of ketoprofen during gastrointestinal tract and prolong the drug's action time.

Uptake of Bile Acid into Calcium-Induced Alginate Gel Beads Containing <i>β</i>-Chitosan Weak Acid Salt

Recently, potential applications for β-chitosan (β-CS) have been examined. In the present study, calcium-induced alginate gel beads (Alg-Ca) containing weak acid salts of β-CS were prepared and examined with regard to their ability to adsorb bile acids in vitro. More than 70% of taurocholate dissolved in solution was taken up by Alg-Ca containing 100 mg β-CS, sim. ilar to the degree of uptake observed with Alg-Ca containing α-CS salt. The adsorption of bile acid was affected by the absolute amount of β-CS and/or the acid concentration of the preparation. A secondary bile acid, taurodeoxycholate, was also adsorbed by Alg-Ca containing weak acid salts of β-CS. Therefore, β-CS might be used to adsorb bile acids within the gastrointestinal tract in the same manner as an anion-exchange resin, and thus serve as a complementary means by which to prevent hyperlipidemia.

溶胶-凝胶法制备TiO_2·SiO_2/beads及其光催化性能的研究

研究以四异丙醇钛 [Ti (iso OC3 H7) 4 ]、硅酸乙酯为原料 ,以空心玻璃微球为载体 ,用溶胶 凝胶法制备可漂浮附载型复合光催化剂TiO2 ·SiO2 /beads的过程 ,利用附载型复合光催化剂降解有机磷农药。结果表明 :附载型复合光催化剂活性显著提高 ,牢固性增强 ,TiO2 ·SiO2 摩尔比存在最佳值。n (TiO2 ) /m (SiO2 ) =30 / 70时 ,光催化剂活性最高 ,其活性是同样降解条件下 ,同样含量DegussaP 2 5TiO2 的

Features of the motion of gel particles in a three-phase bubble column under foaming and non-foaming conditions

Features of the motion of gel particles in a three-phase bubble column with non-foaming and foaming gas–liquid systems,determined by using experiments of radioactive particle tracking(RPT),have been compared.The tracer used is a gel particle which resembles typical immobilized biocatalyst.The tracer trajectory is analyzed to extract relevant information for design purposes.The solid velocity field,turbulence parameters,dispersion coefficients,mixing times and flow transitions are determined and compared.The presence of foam significantly affects many quantified parameters,especially within the heterogeneous flow regime.The hydrodynamic stresses are reduced in the presence of foam,especially close to the disengagement.The dispersion coefficients also decrease,and the solid mixing time is only slightly affected by the presence of foam.Gas holdup,inferred both from RPT experiments and from gamma ray scanning,is higher for foaming systems and leads to a shift in the transition gas velocity towards higher values.

Effects of Shear Fracture on In-depth Profile Modification of Weak Gels

Two sand packs were filled with fine glass beads and quartz sand respectively. The characteristics of crosslinked polymer flowing through the sand packs as well as the influence of shear fracture of porous media on the indepth profile modification of the weak gel generated from the crosslinked polymer were investigated. The results indicated that under the dynamic condition crosslinking reaction happened in both sand packs, and the weak gels in these two cases became small gel particles after water flooding. The differences were： the dynamic gelation time in the quartz sand pack was longer than that in the glass bead pack. Residual resistance factor （FRR） caused by the weak gel in the quartz sand pack was smaller than that in the glass bead pack. The weak gel became gel particles after being scoured by subsequent flood water. A weak gel with uniform apparent viscosity and sealing characteristics was generated in every part of the glass bead pack, which could not only move deeply into the sand pack but also seal the high capacity channels again when it reached the deep part. The weak gel performed in-depth profile modification in the glass bead pack, while in the quartz sand pack, the weak gel was concentrated with 100 cm from the entrance of the sand pack. When propelled by the subsequent flood water, the weak gel could move towards the deep part of the sand pack but then became tiny gel particles and could not effectively seal the high capacity channels there. The in-depth profile modification of the weak gel was very weak in the quartz sand pack. It was the shear fracture of porous media that mainly affected the properties and weakened the in-depth profile modification of the weak gel.

壳聚糖-果胶凝胶珠吸附剂的改性及其去除藻蓝蛋白中Pb(Ⅱ)的应用

壳聚糖-果胶凝胶珠(Chitosan-pectin gel beads,CPB)吸附去除食品中重金属具有较高的潜力,为提高其稳定性、再生利用性及吸附能力,本文采用明胶(Gel)和羧甲基纤维素钠(CMC)对CPB进行改性,利用扫描电镜(SEM)、比表面积与孔隙度分析(BET)、傅里叶变换红外光谱(FTIR)、热重分析(TG)、Zeta电位仪、X射线光电子能谱(XPS)及等技术表征其结构特性,优化吸附解析条件,并评估其对藻蓝蛋白中Pb(Ⅱ)的实际去除效果。结果显示,与CPB和Gel-CPB相比,CMC改性的CPB(CMC-CPB)热稳定性高、表面粗糙多孔、比表面积大(20.28±1.35 m^(2)/g)及Zeta电位低,对金属离子吸附能力强,且解析再生利用率高。FTIR图谱分析显示改性前后CPB官能团结构未发生明显变化,其主要结构官能团为羧基、羟基和氨基。TG分析表明改性前后的CMC-CPB的热稳定性显著高于CPB和Gel-CPB(P<0.05)。XPS光谱分析表明三种吸附剂成功吸附了Pb(Ⅱ),其中CMC-CPB对Pb(Ⅱ)的吸收峰最强。三种吸附剂(CPB、Gel-CPB和CMC-CPB)去除Pb(Ⅱ)的最佳pH和温度分别为6.0和60℃,对Pb(Ⅱ)的吸附过程均符合Langmuir吸附等温模型(R^(2)=0.9543~0.9811)和准二级动力学模型(R^(2)=0.9963~0.9991),该吸附属于单分子层化学吸附,即-COO、-OH、-CO-NH与Pb(Ⅱ)之间的络合作用。根据Langmuir模型曲线评估,CMC-CPB对Pb(Ⅱ)的最大吸附容量q_(max)为69.37 mg/g,显著高于Gel-CPB和CPB(P<0.05)。综合在藻蓝蛋白中的应用效果,CMC-CPB低成本高效安全地去除藻类和藻蓝蛋白食品中Pb(Ⅱ)具有更广阔的前景。

改性海藻酸钠凝胶球去除稀土废水中的U(Ⅵ)

通过一步滴定凝胶法制备了三聚氰胺协同戊二醛改性海藻酸钠复合生物材料(Me@SA/GA),用于稀土废水中U(Ⅵ)的去除。结果表明,Me@SA/GA制备时SA∶Me最优比例为3∶1,当U(Ⅵ)初始浓度为5 mg/L,pH值为5时,静态吸附试验中,Me@SA/GA投加量0.1 g/L,吸附15 h,对水中U(Ⅵ)的吸附量达到19.75 mg/g;动态吸附试验中,以1 mL/min的流速过柱,Thomas模型拟合其饱和吸附量为526.6 mg/g。傅里叶变换红外光谱(FTIR)、X射线光电子能谱仪(XPS)表征结果表明Me@SA/GA吸附U(Ⅵ)的相互作用包括静电吸引、颗粒内扩散以及水凝胶的官能团(羧基、氨基和羟基)与U(Ⅵ)的配位。当Me@SA/GA投加量为1 g/L,对某实际稀土废水进行试验,其出水U(Ⅵ)浓度为0.02 mg/L,可达到我国稀土工业污染物排放标准(GB 26451—2011)要求。

滤棒加香技术研究进展

滤棒加香在卷烟降焦减害工作中作用重要,加香方式也多样丰富。综述了加爆珠、凝胶、香线和颗粒材料四种滤棒加香技术,以期为加香滤棒研发提供参考。

海藻酸钠/碳纳米管复合凝胶球的制备及其吸附性能

提出一种安全简单污水处理的方法,以物理共混的方法利用海藻酸钠分散未经任何处理的原始多壁碳纳米管,得到均匀分散的海藻酸钠/碳纳米管(SA/MWNTs)水溶液,以CaCl2作为凝固浴,制备SA-Ca和SA/MWNTs-Ca复合凝胶球,利用凝胶球对甲基橙(MO)溶液进行吸附脱色研究。试验结果表明:海藻酸钠凝胶球对甲基橙去除率较低,随着碳纳米管含量的增加,当MWNTs增加到2.5g/L,SA/MWNTs-Ca凝胶球的吸附性能提高了3倍;并且随着凝胶球量的增加,去除率迅速增加,当凝胶球质量浓度从1～50g/L时,去除率有显著提高,增加近10倍;溶液pH值对吸附性能的研究还表明,溶液的pH值对SA/MWNTs-Ca凝胶球的吸附性能有较大的影响,pH值较低时有利于SA/MWNTs-Ca凝胶球对MO的吸附。

海藻酸钙凝胶微球的制备和pH依赖性溶胀

利用海藻酸钠溶液与氯化钙溶液发生胶凝反应,本文用滴制的方法制备了海藻酸钙凝胶微球,并对制备的处方和工艺进行了探讨,同时考察了海藻酸钙凝胶微球的特征和溶胀特性。干燥的凝胶微球在不同pH的水性介质中溶胀特性不同。海藻酸钙凝胶微球的这种溶胀的pH敏感性,使其能成为口服药物缓释制剂的载体。

海藻酸钙凝胶微丸作为口服缓释给药载体的研究

将海藻酸钠溶液滴入胶凝剂氯化钙溶液中制备了海藻酸钙凝胶微丸。以胶凝过程中凝胶微丸重量变化 (失水量 )研究了胶凝速率及不同浓度海藻酸钠溶液 ( 1 %～ 4 % )与氯化钙溶液 ( 0 0 5～0 2 0mol/L)对胶凝速率的影响 ,结果是 6h前胶凝速率快 ,随后减慢 ,约 70h胶凝完全 ,氯化钙溶液的浓度≥ 0 1mol/L对胶凝速率无明显影响。干燥的凝胶微丸在不同水性介质中溶胀试验结果表明 :在温度约 37℃时 ,微丸在蒸馏水和 0 1mol/L盐酸 ( pH1 0 )中几乎不溶胀 ,而在磷酸盐缓冲溶液( pH6 8)中1h溶胀 ,溶胀后的微丸直径是干燥前湿微丸直径的 1 80 %。海藻酸钙凝胶微丸这种溶胀的 pH敏感性 ,使它能成为口服药物缓释制剂的载体。以硝苯地平为模型药物制备的海藻酸钙凝胶微丸 ,其体外释放试验结果 ,2h累积释放量为 2 0 %～ 30 % ,6h为 6 0 %～ 80 % ,1 2h时大于85 %。药物从微丸中的释放是以扩散和骨架溶蚀相结合的方式。由此可见 。

阿西美辛海藻酸钙凝胶微丸释药影响因素考察

目的:考察阿西美辛海藻酸钙凝胶微丸的释药机制。方法:采用滴制法制备阿西美辛海藻酸钙微丸,考察海藻酸钠浓度,钙离子浓度,投药量,滴头直径大小对药物释放的影响。结果:海藻酸钠浓度增加,钙离子浓度增加,滴头直径增加,释药速率减慢。结论:在体外释放度实验中,阿西美辛海藻酸钙凝胶微丸具有良好的缓释作用,海藻酸钙凝胶微丸是一种非常有潜力的药物载体。

海藻酸钠凝胶球对水中无机磷的吸附性能

利用一定质量分数的海藻酸钠(SA)滴入Ca2+、Fe3+等溶液中会形成规则球形的特性制备凝胶球,用于处理含磷废水。研究了不同凝胶球的除磷特性及除磷效果,并对腐殖酸与无机磷混合溶液进行吸附研究。实验结果表明,凝胶球对无机磷具有很强的吸附性能,该技术具有工艺简单、处理效率高、速度快等优点。吸附时间16h,海藻酸钠—钙—铁(Ⅲ)凝胶球对200mL(TP=50mg/L)的模拟污水去除率接近50%,海藻酸钠—铁(Ⅲ)凝胶球对磷的去除率可接近97%。海藻酸钠—钙—铁(Ⅲ)凝胶球在酸性条件下比较稳定,在碱性条件下易被分解。Langmuir型方程式可以较好地描述海藻酸钠—钙—铁(Ⅲ)凝胶球对磷的吸附行为,最大吸附量为1428.6mg/g,海藻酸钠最佳制备质量分数为2%。研究结果还表明,海藻酸钠—钙—铁(Ⅲ)凝胶球可以选择性去除与腐殖物质共存水体中的磷。

黄连素海藻酸钙凝胶小球制备工艺及释药特性研究

目的:考察不同条件下制备的黄连素海藻酸钙凝胶小球的pH值依赖性释放。方法:用浸渍法制备黄连素的海藻酸钙凝胶小球。通过黄连素溶液的浓度,海藻酸钠溶液的浓度和交联时间这三个因素,来考察黄连素凝胶小球的制备工艺,并在模拟胃液和肠液pH环境下,测试其释放行为。结果:黄连素浓度的提高,有利于载药量的提高;而海藻酸钠浓度的提高,会使载药量降低;交联时间对载药量的影响很小。实验证明,载药量最高可以达到16%,与黄连素同类药物相比,显著提高了载药量。最佳工艺小球在pH 1.0的介质中几乎不溶胀,2个小时累积释放不到10%,而在模拟肠液的pH7.4环境中,6个小时的累积释放达到70.14%,24 h累积释放达到98.21%。结论:该黄连素凝胶小球具有较好的缓控释效果,可以降低黄连素对胃部的刺激并可应用于黄连素对溃疡性结肠炎的治疗。

离子交换层析分离纯化重组人血清白蛋白

通过层析实验 ,比较了几种阴离子交换剂在不同温度、p H值、离子强度、进样流速、进样浓度下对人血清白蛋白的吸附与脱附性能 ,研究了它们对人血清白蛋白和卵清蛋白的分离能力 ,并考察了柱层析过程中吸附载体对重组人血清白蛋白和杂蛋白的分离选择性。实验结果表明 :牌号为DEAE Sepharose FF的载体不仅对重组人血清白蛋白具有良好的分离度 。

不同离子交联剂对海藻酸凝胶微丸溶胀和释药性质的影响

目的考察不同离子交联剂对海藻酸凝胶微丸溶胀和释药性质的影响。方法以考马斯亮兰G-250为模型药物,分别以Ca2+,Fe3+,Zn2+,Ba2+为交联剂,采用滴制法制备海藻酸凝胶微丸,考察不同离子交联制备的海藻酸凝胶微丸吸水溶胀和释药行为的差异。结果不同离子交联制备的海藻酸凝胶微丸的溶胀行为和释药行为有明显差异。结论海藻酸凝胶微丸是一种非常有潜力的药物载体,可通过采用不同离子交联制备获得不同缓释效果。

PVA凝胶小球在废水生物处理工艺中的应用

PVA凝胶小球是一种亲水性好、具有良好细菌栖息性的新型微生物固定化载体。以PVA凝胶小球为载体,分析研究其在废水厌氧、好氧及脱氮生物处理工艺中的应用现状,指出PVA生物处理系统具有微生物富集量高、系统启动快、容积负荷高、CODCr及TN去除率高等明显的技术优势。针对不同类型废水开展PVA生物处理工艺基础试验研究以及工程化实践,是一个值得关注的发展趋势。