硫酸对壳聚糖膜分离性能影响的本质

研究了Ｈ２ＳＯ４对壳聚糖（ＣＳ）膜醇水分离性能的影响．结果表明，Ｈ２ＳＯ４使ＣＳ上的—ＮＨ２质子化为—ＮＨ＋３，降低了极性较差的乙醇分子进入膜内的能力，提高了膜对水分子的吸附选择性．又因为ＳＯ２－４可以与２个—ＮＨ＋３作用，使部分ＣＳ链产生交联，缩小了分子透过的通道．由于乙醇分子比水分子大，故大大提高了膜对水的渗透选择性．所以，Ｈ２ＳＯ４能提高ＣＳ膜的醇水分离性能是以上两种因素综合作用的结果．     

球形Ni2+模板交联壳聚糖吸附剂的多胺化及其对Ni2+的吸附性能

多胺化合成球形Ni2 模板交联壳聚糖吸附剂,该吸附剂对重金属镍离子具有更好的吸附能力.试验结果表明,通过模板化、胺化使吸附容量由1.072mmol/g提高到2.746mmol/g.通过不同吸附剂的红外光谱分析、含水率和Ni2 吸附容量的比较,验证了技术路线的正确性.研究了吸附剂对Ni2 的吸附性能,其对Ni2 的吸附具有较好的动力学性能.     

汞离子天然吸附剂

汞离子是现代工业中剧毒的污染物之一,研究者致力于汞离子高效吸附剂的研制已有多年.本文基于国内外最新研究文献,系统论述了汞离子天然吸附剂如壳聚糖、矿物、微生物及其改性材料等的吸附性能,并详细比较了各种吸附剂的优缺点,指出天然吸附剂来源广泛、价格便宜,尤其是修饰后的壳聚糖吸附性能甚至可以和一些合成吸附剂相媲美.在所报道的天然吸附剂中,引入巯基后的戊二醛交联壳聚糖,对初始浓度为500 mg/L的汞离子的吸附容量可达1 604.7mg/g,属已知的汞离子天然吸附剂中之最.天然汞离子吸附剂在工业废水处理中显示出了广阔的应用前景.     

交联壳聚糖对氨基酸的吸附性能

本文研究了交联壳聚糖对甘氨酸、谷氨酸和赖氨酸的吸附性能，吸附率依次为甘氨酸＞赖氨酸＞谷氨酸，并决定于上柱液的ＰＨ值及其浓度。用０．０５和０．１ｍｏｌ／ｌＮＨ４ＯＨ可以解吸。     

金属－助剂相互作用对SiO_2载铑催化剂化学吸附的影响──Ⅱ．Rh－V／SiO_2催化剂

由ＲｈＣｌ_３·ｘＨ_２Ｏ制备了不同Ｒｈ含量的Ｒｈ／ＳｉＯ_２和Ｒｈ－Ｖ／ＳｉＯ_２催化剂，采用化学吸附和原位ＴＰＤ－ＩＲ方法考察钒助剂对Ｒｈ／ＳｉＯ_２催化剂在常温和高温的Ｈ_２和ＣＯ化学吸附的影响。结果再次表明：１）不同Ｒｈ中心对Ｈ_２和ＣＯ的化学吸附性能不同，钒助剂对不同Ｒｈ中心的Ｈ_２和ＣＯ吸附的影响也不同。Ｈ_２主要吸附在Ｒｈ~Ⅱ和Ｒｈ~Ⅲ中心上，而在Ｒｈ~Ⅰ中心上的吸附弱。２）Ｒｈ－钒助剂的强相互作用主要是Ｒｈ~Ⅱ和Ｒｈ~Ⅲ与钒助剂之间的相互作用，Ｈ_２吸附受到比ＣＯ吸附更强烈的抑制。钒助剂对Ｒｈ／ＳｉＯ_２的Ｈ_２和ＣＯ吸附性能的影响可用覆盖模型解释。     

壳聚糖对Cu^2＋吸附行为及机理研究

用间歇吸附法研究了壳聚糖对Ｃｕ＾２＋的吸附性能,考察了壳聚糖脱乙酰化度、分子量对吸附性能的影响及等温吸附情况,并利用ＸＰＳ技术研究了吸附前后壳聚糖中Ｎ、Ｏ、Ｃ元素及Ｃｕ＾２＋的结合能变化,结合物质结构性能,探讨了壳聚糖吸附Ｃｕ＾２＋的吸附机理。     

交联壳聚糖对重金属离子吸附性能的研究进展

壳聚糖分子中含有大量的氨基和羟基,可以进行多种化学改性.本文综述了四类交联剂(醛类、环氧氯丙烷、聚乙二醇类以及冠醚)交联壳聚糖对重金属离子的吸附研究进展.从吸附剂在酸性条件下的稳定性、对某种或者某些离子的选择吸附性能、吸附容量以及可再生能力等方面讨论了各种吸附剂的性能.此外,加强吸附机理研究是今后研究的方向之一.     

交联聚乙烯醇水凝胶对胆红素的吸附性能研究

本文采用反相聚合的方法以戊二醛为交联剂合成了珠状交联聚乙烯醇凝胶，并研究了它对胆红素的吸附性能。结果表明交联聚乙烯醇对胆红素的体外吸附率受到吸附剂的交联度、颗粒直径、溶液中白蛋白的浓度、吸附温度及离子强度的影响。该类吸附剂对胆红素具有良好的吸附动力学性能。     

壳聚糖吸附剂的制备及其性能

本文以壳聚糖为主要原料，分别经过悬浮交联和复合制备得到壳聚糖（Ｃｈｉｔｏｓａｎ）树脂吸附剂（简称ＣＳ吸附剂）和壳聚糖—活性炭（Ｃｈｉｔｏｓａｎ－Ａｃｔｉｖｅｃａｒｂｏｎ）复合吸附剂（简称ＣＳ—ＡＣ吸附剂）。研究影响制备吸附剂的诸因素；测定两种吸附剂的性能；探讨两种吸附剂对印染废水的脱色和对有毒金属离子的去除。研究结果表明：本研究条件下制得的ＣＳ和ＣＳ—ＡＣ吸附剂比表面积分别为８２．９Ｍ２／ｇ和９３７．３Ｍ２／ｇ；对亚甲基蓝溶液（５００ｍｇ／Ｌ）的静态吸附量为１４１．２ｍｇ／ｇ吸附剂和８３５．１ｍｇ／ｇ吸附剂；ＣＳ吸附剂对印染废水的动态脱色量为１２６．９ｍｇ／ｇ吸附剂；两种吸附剂对有毒重金属Ｐｂ（２＋）的去除率均达９０％以上，而且耐酸、碱性能较好，均为优良的颗粒状吸附剂。     

含牛磺酸交联聚乙烯醇的合成及其对甘油三脂吸附性能*

以牛磺酸修饰交联聚乙烯醇凝胶合成了吸附剂。吸附实验结果表明：该类吸附剂对血清中甘油三脂具有良好的吸附效果,而对血清中总蛋白的吸附性能相对较弱。它们对甘油三脂的吸附性能着吸附剂上功能基含量的增加而加强,但随着载体的交联度的提高而降低。血清中致病因子的浓度影响吸附性能。     

A Modified Chitosan Adsorbent for Selective Removal of Low Density Lipoprotein

A modified chitosan adsorbent was synthesized through a simple preparation procedure,and it demonstrated good adsorption performance for selective removal of low density lipoprotein in human plasma. Phase inversion technique was employed to form chitosan beads, to which epoxy groups were then introduced by reacting with ethyleneglycol diglycidylether, and tryptophan was subsequently coupled to the epoxy-activated beads.     

Adsorption of tannic acid, humic acid, and dyes from water using the composite of chitosan and activated clay

Chitosan is a well-known excellent adsorbent for a number of organics and metal ions, but its mechanical properties and specific gravity should be enhanced for practical operation. In this study, activated clay was added in chitosan slurry to prepare composite beads. The adsorption isotherms and kinetics of two organic acids (tannic acid, humic acid) and two dyes (methylene blue, reactive dye RR222) using composite beads, activated clay, and chitosan beads were compared. With composite beads as an adsorbent, all the isotherms were better fitted by the Freundlich equation. The adsorption capacities with composite beads were generally comparable to those with chitosan beads but much larger than those with activated clay. The pseudo-first-order and pseudo-second-order equations were then screened to describe the adsorption processes. It was shown that the adsorption of larger molecules such as tannic acid (MW, 1700 g mol(-1)), humic acid, and RR222 from water onto composite beads was better described by the pseudo-first-order kinetic model. The rate parameters of the intraparticle diffusion model for adsorption onto such adsorbents were also evaluated and compared to identify the adsorption mechanisms.     

A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin.Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization.Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads.The effects of reaction conditions,such as crosslinking time,the amount of crosslinking agent and the NaOH concentration,on the physical properties of the chitosan beads were investigated.The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde.The capacity for copper ions in as high as 40mg/g,The beads have good mechanical strength and can be reused.     

A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

1. INTRODUCTION Chitosan is the deacetylated chitin which is one of the most abundant natural polymers produced from crab, lobster and shrimp shells or fungal fermentation processes [1]. It is a family of deacetylated β1→4 D-glucosamine polymers. Chitosan has properties including bioactivity, biocompatibility and biodegradability, so it is potentially more useful than cellulose for developing advanced of attention not only as an unutilized biomass resource but also as a novel type of sp…     

尿毒症中分子毒物吸附剂的研究(Ⅰ)——戊二醛交联壳聚糖吸附剂

长期以来 ,血液净化疗法一直是临床上处理各种血液中毒的基本手段[1～ 3] .对尿毒症患者 ,目前普遍采用的治疗措施是对其进行定期的血液或腹膜透析 [1] 缓解病情 ;然而单纯血液透析疗法难以清除患者体内的中分子毒物 ,以致血液透析的患者体内 ,中分子毒物的积累会达到很高的程度 .因此 ,通过研制高效的中分子吸附剂 ,以血液灌流的方式清除中分子毒物 ,对于控制和治疗尿毒症具有重要意义 .据文献报道 ,体内蓄积的中分子毒物中肽类物质占了一定的比例[4～ 9] ,患者的许多顽固临床症状与这些毒物的体内蓄积密切相关 [1,10 ] .本课题组的研究结…     

Adsorption of anionic dye by anionic surfactant modified chitosan beads: Influence of hydrophobic tail and ionic head-group

In this paper, how chitosan hydrogel beads were modified by anionic surfactants (SDS, SDOS, SDBS, AOT, and DTM-12) and then used for the adsorption and removal of an anionic dye (congo red) from aqueous solutions were described. The effect of surfactant concentration, surfactant ionic head-group, and surfactant hydrophobic tail were investigated in detail. The result revealed the modified CS beads all had the obviously higher adsorption capacity than CS beads. Compared to the ionic head-group, the hydrophobic tail of the surfactant plays more important role in the adsorption, and a high adsorption capacity was observed for CS/AOT beads and CS/DTM-12 beads (both with two hydrophobic tails). The Sips isotherm model showed a good fit with the equilibrium experimental data, and the values of the heterogeneity factor (n) indicated heterogeneous adsorption. The adsorption kinetics analysis indicated that the pseudo-second-order rate model could better describe the adsorption process than the pseudo-first-order rate model.     

Preparation of ion-exchange beads based on poly(methacrylic acid) brush grafted chitosan beads: Isolation of lysozyme from egg white in batch system

Poly(methacrylic acid) brush grafted crosslinked-chitosan (chitosan-g-poly(MAA)) beads were prepared in two sequential steps: in the first step, chitosan beads were prepared by phase-inversion technique and then were crosslinked with epichlorohydrin under alkaline condition; in the second step, the graft copolymerization of methacrylic acid onto the chitosan beads was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan-g-poly(MAA) beads were first used as an ion exchange support for adsorption of lysozyme (LYZ) from aqueous solution. The influence of pH, equilibrium time, ionic strength and initial LYZ concentration on the adsorption capacity of the chitosan-g-poly(MAA) ion-exchange beads has been investigated in a batch system. Maximum LYZ adsorption onto chitosan-g-poly(MAA) beads was found to be 65.7 mg/g at pH 6.0. The experimental equilibrium data obtained LYZ adsorption onto chitosan-g-poly(MAA) ion-exchange beads fitted well to the Langmuir isotherm model. Kinetics parameters of this adsorption system were also analyzed by using the equilibrium experimental data. The result of kinetic analyzed for LYZ adsorption onto ion-exchange beads showed that the second order rate equation was favourable. Finally, the chitosan-g-poly(MAA) ion-exchange beads were used for the purification of LYZ from egg white in batch system and the purity of the eluted LYZ from ion-exchange chitosan-g-poly(MAA) beads was determined as 94% by HPLC from single step purification.     

改性壳聚糖树脂对利尿剂的吸附性能

用琥珀酸酐、苯甲酸酐、聚乙烯亚胺和 3 氯 2 羟丙基三甲基氯化铵对壳聚糖进行改性 ,分别在其氨基上引入羧基、苯环、多氨基和季胺基 ,并利用红外谱图对于改性后的壳聚糖的结构进行了分析 .应用相转移法制备了 4种改性壳聚糖的微球 ,实验研究了这 4种微球对 9种不同利尿剂的吸附性能 .结果表明 ,由于Lewis酸碱相互作用 ,引入羧基后的壳聚糖树脂对 3种碱性利尿剂的吸附量有了 15 %～ 36 %的提高 ,而引入多氨基的壳聚糖树脂对四种酸性利尿剂的吸附量分别提高了 4 8 5 %～ 2 0 9% ;由于苯环和利尿剂的憎水性基团的相互作用 ,引入苯环后的壳聚糖树脂对所有的利尿剂的吸附量都有所提高 ,其幅度为 15 %～ 6 1% ;因为季胺基团和羧基之间发生的离子交换作用 ,引入季胺基后的树脂对具有羧基的利尿剂吸附量有显著的提高 ,尤其对布美它尼的吸附量提高了 2倍以上 .     

Macroporous copolymer matrix. IV. Expanded bed adsorption application

Macroporous crosslinked hydroxyethyl methacrylate-ethylene dimethacrylate copolymeric beads (HEG beads) were synthesized by suspension polymerization in the presence of a pore generating agent. These beads were coupled to alpha-cyclodextrin through a urethane spacer. These modified copolymer beads (affinity-HEG beads) so prepared were evaluated for their suitability in expanded bed chromatography. The optimum thickness of the distributor plate for stable expanded bed for use in expanded bed adsorption (EBA) was established. The affinity-HEG beads are comparable in density to Streamline diethyl amino ethane (DEAE) and exhibit better mechanical stability at higher superficial velocity under fluidization. The affinity-BEG beads were used as affinity chromatography matrices for the purification of cyclodextrin glycosyltransferase. Feeding of 5-fold diluted fermented broth to the column containing affinity-HEG beads of settled bed height 7.5 cm (I.D. 26 mm and length 42 cm) at double bed expansion resulted in a sharp breakthrough curve of alpha-cyclodextrin glycosyltransferase (CGTase). The adsorbed enzyme was eluted from the bed in 50 mM Tris-HCl buffer containing 10 mM CaCl2 at 25 degrees C in packed bed configuration.     

The separation of GMP from milk whey using the modified chitosan beads

The cationic property of chitosan was used to adsorb glycomacropeptide (GMP) molecules from milk whey proteins. β-cyclodextrin was immobilized to native chitosan beads by cross-linking with 1,6-hexamethylene diisocyanate (HMDI). The resultant modified beads (CS-HMDI-BCD) presented superior adsorption affinity and capacity towards GMP. At pH 3.0, 90.23% of GMP was adsorbed with a maximum adsorption capacity corresponding to 12.87 mg of sialic acid/g-adsorbent. Desorption experiments showed that the modified beads could be regenerated and used in many cycles without significant decreases in the capacity and selectivity.