胺化羧甲基改性磁性壳聚糖的制备及吸附性能研究

采用交联法制备了磁性壳聚糖,并在此基础上使用柠檬酸及二乙烯三胺对其进行化学改性,得到了磁性能良好、颗粒分布均匀、平均孔径为4.37 nm的胺化羧甲基改性磁性壳聚糖。将其用于模拟废水中进行静态吸附实验。结果表明,改性后的磁性壳聚糖在保证机械强度与回收率的基础上,提高了磁性壳聚糖的吸附性能,在最适pH=6的条件下,对Cu~(2+)、Cd~(2+)、Ni~(2+)的吸附容量分别达到76.82、54.15、62.64 mg/g。     

Studies of adsorption of alkaline trypsin by poly(methacrylic acid) brushes on chitosan membranes

Poly(methacrylic acid)‐grafted chitosan membranes (chitosan‐g‐poly(MAA)) were prepared in two sequential steps: in the first step, chitosan membranes were prepared by phase‐inversion technique and then epichlorohydrin was used as crosslinking agent to increase its chemical stability in acidic media; in the second step, the graftcopolymerization of methacrylic acid onto the chitosan membranes was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan‐g‐poly(MAA) membranes were first used as an ion‐exchange support for adsorption of trypsin from aqueous solution. The influence of pH, equilibrium time, ionic strength, and initial trypsin concentration on the adsorption capacity of the chitosan‐g‐poly(MAA) membranes have been investigated in a batch system. Maximum trypsin adsorption onto chitosan‐g‐poly(MAA) membrane was found to be 92.86 mg mL^?1 at pH 7.0. The experimental equilibrium data obtained for trypsin adsorption onto chitosan‐g‐poly(MAA) membranes fitted well to the Langmuir isotherm model. The adsorption data was analyzed using the first‐ and second‐order kinetic models, and the experimental data was well described by the second‐order equation. More than 97% of the adsorbed trypsin was desorbed using glutamic acid solution (0.5M, pH 4.0). In addition, the chitosan‐g‐ poly(MAA) membrane prepared in this work showed promising potential for various biotechnological applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

丙酮酸改性壳聚糖对金属离子的吸附性能研究

丙酮酸经Schiff碱反应对壳聚糖进行修饰 ,合成了高取代的水溶性丙酮酸缩壳聚糖 (PCTS) ,研究了PCTS、SCTS(水杨醛改性壳聚糖 )、CTS(壳聚糖 )对Cu(Ⅱ )、Zn(Ⅱ )、Co(Ⅱ )的静态吸附性能 ,并采用正交实验法考察了金属离子浓度、介质酸度、吸附量和吸附时间对吸附剂去除金属离子能力的影响。结果表明 ,PCTS的吸附性能优于SCTS与CTS ,对Cu(Ⅱ )、Zn(Ⅱ )、Co(Ⅱ )的吸附容量 (pH =7 0 )分别为 2 79 56、1 96 63、70 2 1mg/g ,金属离子浓度、介质酸度对吸附性能影响大 ,而吸附剂用量、吸附时间对吸附性能影响较小。     

壳聚糖表面活性剂的制备及其表面性能

以壳聚糖为原料制备系列O-羟丙基-N-烷基化壳聚糖表面活性剂Cn-HPCS。通过IR和1HNMR对Cn-HPCS的结构进行表征;通过测定其表面张力(γ),临界胶束浓度(cmc),HLB值和泡沫性能等对其表面性能进行评价。结果表明,Cn-HPCS的cmc为0.016～0.05 mmol/L,HLB值为5.33～13.89,并具有良好的泡沫性能且乳化性能优于Tween 60。     

树脂吸附法固定Candida rugosa脂肪酶

Candida rugosa脂肪酶具有优良的催化性能,对其进行固定化可以很方便地实现酶的回收和再利用。采用南开大学化工厂生产的4种阴离子交换树脂和4种大孔吸附树脂为载体,对来源于Candida rugosa的脂肪酶进行了吸附固定化,结果表明,以大孔吸附树脂AB-8为载体的固定酶比活性最高。固定化酶制备过程中缓冲液的最适宜pH值为7.2,最佳固定化时间为1 h,载体和酶的最佳质量配比为10∶1。与游离酶相比,固定化后酶活损失大约30%,但稳定性平均约提高60%。     

Improved antimicrobial activity of polypropylene and cotton nonwoven fabrics by surface treatment and modification with chitosan

Nonwoven polypropylene and cotton fabrics were subjected to plasma pretreatment followed by flash evaporation and radiation crosslinking acrylate polymer coating, which is based on a vacuum deposition, solvent free, process that produces high quality, uniform fabrics with various thicknesses (0.05–5.0 μm). These treated fabrics were then dipped into chitosan, carboxymethyl chitosan, and carboxymethyl chitin solution. These polysaccharides form strong complexes with the modified surface. The antimicrobial activity of these treated samples was then evaluated for their antifungal and antibacterial properties. The antifungal activity for Fusarium oxysporum f. sp. lycopersici, Verticillium albo‐atrum, and Alternaria solani (A. alternata) were examined by the disc plate method. The antibacterial activities of the modified fabrics against Clavibacter michiganensis and Pseudomonas solanacearum were also examined by the viable cell counting method. The inhibition zone of the chitosan covered samples has increased by a factor of 2–3.1 over the original pretreated samples. The chitosan‐modified fabrics showed a good antibacterial activity in killing almost 10⁵ cells/mL within 18–23 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Cr (VI) adsorption from aqueous solutions on grafted chitosan

Chitosan was grafted on the surface of a cotton gauze (20, 50, and 100 mg chitosan g⁻¹ cotton) to improve its stability in aqueous solutions. The adsorption of hexavalent chromium ions from water on the grafted chitosan was evaluated to determine, by means of linear and nonlinear models, the kinetic and isotherm adsorption of the process. The kinetics of pseudo second-order, pseudo first-order, and adsorption isotherms type II were obtained, that is, a monolayer adsorption on nonporous adsorbents with physical adsorption was present. The most probable energy of adsorption corresponded to a physisorption with hydrogen bond interactions between chromium ions and ammonium groups. Moreover, three different cross-sectional areas of hexavalent chromium ions were calculated and used to estimate the specific surface area employed by active sites to adsorb metal ions in terms of chitosan or cotton mass. Finally, the percentage of the area occupied by chromium ions on the surface was estimated by dividing the resulting specific surface area in terms of cotton mass by the specific surface area of cotton reported in literature. As a result, it was determined that the occupied area is between 6% (for 20 mg chitosan g⁻¹ cotton)-24% (for 100 mg chitosan g⁻¹ cotton) from the total area of cotton.     

壳聚糖/活性炭纤维复合膜的制备及对甲基橙的吸附研究

通过化学交联法制备了纯壳聚糖膜和壳聚糖/活性炭纤维复合膜(质量比为1∶1.1);探讨时间、pH值、温度、甲基橙溶液初始浓度以及吸附剂用量对吸附甲基橙的影响。研究结果表明,最佳吸附时间为120 min,在pH为6.0,甲基橙初始浓度10 mg/L,温度为10℃时,膜对甲基橙的吸附效果最好,去除率达99.54%。     

Microwave preparation and adsorption properties of EDTA‐modified cross‐linked chitosan

A novel chitosan‐based adsorbent (CCTE) was synthesized by the reaction between epichlorohydrin O‐cross‐linked chitosan and EDTA dianhydride under microwave irradiation (MW). The chemical structure of this new polymer was characterized by infrared spectra analysis, thermogravimetric analysis, and X‐ray diffraction analysis. The results were in agreement with the expectations. The static adsorption properties of the polymer for Pb²⁺, Cu²⁺, Cd²⁺, Ni²⁺, and Co²⁺ were investigated. Experimental results demonstrated that the CCTE had higher adsorption capacity for the same metal ion than the parent chitosan and cross‐linked chitosan. In particular, the adsorption capacities for Pb²⁺ and Cd²⁺ were 1.28 mmol/g and 1.29 mmol/g, respectively, in contrast to only 0.372 mmol/g for Pb²⁺ and 0.503 mmol/g for Cd²⁺ on chitosan. Kinetic experiments indicated that the adsorption of CCTE for the above metal ions achieved the equilibrium within 4 h. The desorption efficiencies of the metal ions on CCTE were over 93%. Therefore, CCTE is an effective adsorbent for the removal and recovery of heavy metal ions from industrial waste solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

壳聚糖/聚乳酸复合膜的制备及其吸附性能

为了减小水处理废弃膜对环境的危害,以静电纺聚乳酸(PLA)纤维膜为基底层,采用浸涂的方式将壳聚糖(CS)涂覆层与PLA基底层复合形成了CS/PLA复合膜。采用SEM、XRD对其进行了表征。考察了CS与PLA体积比对膜性能的影响。结果发现,当CS和PLA体积比为7∶5时,CS涂覆层表面致密且平整,其厚度为7μm,CS/PLA复合膜的拉伸强度为2.55 MPa,断裂伸长率为24.96%,纯水通量为115.32 L/(m²·h),对酸性染料的渗透通量为99.43 L/(m²·h),吸附率达96%;对牛血清蛋白和卵清蛋白的吸附率分别为86%和84%;对Cu²⁺、Pb²⁺和Cd²⁺的平衡吸附量分别为165.00、248.54和307.83 mg/g。     

壳聚糖膜的制备及性能测定

以醋酸(HAc)为溶剂溶解原料壳聚糖(黏均分子量117万),流延烘干,经氢氧化钠溶液浸泡,洗涤干燥制得壳聚糖膜。详细考察了HAc浓度、原料浓度、NaOH浓度、碱液浸泡时间、增塑剂用量等因素对膜拉伸性能的影响。确定了最佳反应条件,即HAc浓度3%,原料浓度1.5%,NaOH浓度6%,碱液浸泡时间3 h,甘油加入量8%。在此条件下,壳聚糖膜的拉伸强度为88.74 MPa,断裂伸长率14.3%。     

Plasma‐induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling method

Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma‐graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55 W for 15 min, and the membrane treated at 55 W for 30 min for creatinine were 9.12 × 10^?7, 10.6 × 10^?7 and 8.57 × 10^?7 cm² s^?1, respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification. © 2003 Society of Chemical Industry     

壳聚糖的改性研究

本文简要介绍了壳聚糖的改性     

Study on the adsorption properties of novel crown ether crosslinked chitosan for metal ions

We first synthesized N‐benzylidene chitosan (CTB) by the reaction of benzaldehyde with chitosan (CTS). Chitosan‐dibenzo‐18‐crown‐6 crown ether bearing Schiff‐base group (CTBD) and chitosan‐dibenzo‐18‐crown‐6 crown ether (CTSD) were prepared by the reaction of 4,4′‐dibromodibenzo‐18‐crown‐6 crown ether with CTB and CTS, respectively. Their structures were confirmed by Fourier transform infrared spectral analysis and X‐ray powder diffraction analysis. These novel crown ether crosslinked CTSs have space net structures with embedded crown ethers and contain the double structures and properties of CTS and crown ethers. They have stronger complexation with and better selectivity for metal ions than corresponding crown ethers and CTS. Moreover, these novel CTS derivatives can be used to separate and preconcentrate heavy or precious metal ions in aqueous environments. From this practical viewpoint, we studied the adsorption and selectivity properties of CTB, CTBD, and CTSD for Ag⁺, Cu²⁺, Pb²⁺, and Ni²⁺. The experimental results showed that CTBD had better adsorption properties and higher selectivity for metal ions than CTSD. For aqueous systems containing Pb²⁺–Ni²⁺ and Pb²⁺–Cu²⁺, the selectivity coefficients of CTSD and CTBD were K/Ni²⁺ = 24.4 and K/Cu²⁺ = 41.4 and K/Ni²⁺ = 35.5 and K/Cu²⁺ = 55.3, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 29–34, 2002; DOI 10.1002/app.10180     

壳聚糖衍生物的表面活性及其药物增溶性研究进展

壳聚糖基表面活性剂具有安全无毒和可生物降解等特点,在生物医药和日用化工等行业的应用日益增多。通过双亲性改性获得具有表面活性的壳聚糖所形成的胶束,可以增加难溶药物的溶解度,延长释药时间,提高药物利用率,降低细胞毒性,在药物载体方面具有广阔的应用前景。本文综述了近年来偶联、烷基化、酰基化、羧甲化、季铵化等改性壳聚糖衍生物的表面活性研究以及对紫杉醇、喜树碱、阿霉素和甲氨基叶酸等药物的增溶应用进展。在壳聚糖的改性新方法中有两点值得注意：一是利用疏水相互作用构成自组装体;二是引入具有特殊功能的基团制备智能载药胶束。     

氯丙酸改性壳聚糖对Hg~(2+)的吸附性能研究

研究了改性壳聚糖对重金属Hg2+的吸附特性,包括吸附动力学和吸附等温式,且研究了pH、反应时间对其吸附性能的影响.结果表明:羧乙基壳聚糖对Hg2+的吸附在不同温度下符合Freundlich和Langmuir吸附等温式,吸附过程动力学适合二级反应.当pH为4～6,吸附时间为180 min时,羧乙基壳聚糖对Hg2+有较高吸附效果.     

Preparation and adsorption properties of metal ions of crosslinked chitosan azacrown ethers

The novel azacrown ether chitosan derivatives (CCAE‐I, CCAE‐II) were prepared by reaction between crosslinked chitosan with epoxy‐activated azacrown ethers. Their structures were confirmed by elemental FTIR spectra analysis and X‐ray diffraction analysis. The adsorption and selectivity properties of the crosslinked chitosan azacrown ethers for Pb²⁺, Cu²⁺, Cr³⁺, Cd²⁺, and Hg²⁺ were also investigated. The experimental results showed that they have high adsorption capacity for Cu²⁺, Cd²⁺, and Hg²⁺. The adsorption capacity of CCAE‐II is higher than CCAE‐I for Cd²⁺ and Hg²⁺. The selectivity properties of CCAE are better than chitosan and crosslinked chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3053–3058, 1999     

羧甲基壳聚糖对稀土离子吸附性能的研究

以壳聚糖为原料,在碱性条件下合成了标题化合物,考察了其对稀土离子La3+、Nd3+、Sm3+的吸附性能.讨论了时间、溶液的酸度、初始离子浓度、羧甲基取代度对吸附性能的影响.发现羧甲基壳聚糖对稀土离子有较强的吸附性,吸附性满足Langmuir等温式.     

Synthesis and adsorption properties of metal ions of novel azacrown ether crosslinked chitosan

Azacrown ether chitosan (CTSC) was synthesized by the reaction of chitosan with N‐allyl benzo 15‐crown‐5 crown ether. Azacrown ether crosslinked chitosan (CCTSC) was prepared by the crosslinked reaction of CTSC and epichlorodydrin. Their structures were confirmed by infrared spectral analysis and X‐ray diffraction analysis. The adsorption properties of CTSC and CCTSC for metal ions were also investigated. The experimental results showed that the two chitosan derivatives not only had a good capacity to adsorb Pd²⁺ and Ag⁺ but also was highly selective for Pd²⁺ and Ag⁺ in the coexistence system containing other metal ions. At 20°C ± 1°C and pH = 4, the adsorption capacity of CTSC and CCTSC for Pd²⁺ was 186.1 and 173.1 mg/g, respectively; and for Ag⁺ was 90.2 and 56.5 mg/g, respectively. The selectivity coefficients were K = 6.99, K = ∞, K = 35.38, K = ∞ for CTSC and K = 10.66, K = ∞, K = 85.45, K = ∞ for CCTSC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2705–2709, 2006