纤维素亲和膜对木瓜蛋白酶的吸附特性

以纤维素滤纸膜为载体,染料汽巴蓝F3GA为配基,制备出一种新型亲和膜色谱介质。分别在277,298,310K的均衡实验条件下,批量法对木瓜蛋白酶进行等温吸附测定。所得的数据用准一级动力学模型和准二级动力学模型进行分析。结果表明:准二级动力学模型具有更好的相关性,纤维素染料亲和膜对木瓜蛋白酶的吸附符合Lang-muir吸附模型,在298K条件下吸附现象的热力学参数:ΔGΘ,ΔHΘ,ΔSΘ分别为-7.71kJ/mol,34.91kJ/mol和0.143kJ/(mol.K),染料纤维素亲和膜对木瓜蛋白酶的吸附是自发的,并且是吸热过程。     

腐植酸及其树脂对水中三价铬吸附性能的研究

以腐植酸为原料,酚醛树脂为交联固化剂,合成颗粒状腐植酸树脂。研究了该树脂及腐植酸在不同pH、初始质量浓度、振荡时间条件下对Cr3+的吸附性能。结果表明,腐植酸对Cr3+的吸附量及吸附率随浓度、时间和pH的变化而变化,其最佳条件为pH=5,t吸附为150min,ρ(Cr3+)为100mg/L。腐植酸树脂对Cr3+的吸附性能受时间影响较小,最佳质量浓度及pH与腐植酸吸附基本相同。腐植酸及其树脂的Γ饱和分别为15.50 mg/g和19.66 mg/g。     

交联羧甲基纤维素的制备及对染料吸附性能的研究

酸催化下,取代度0.82的羧甲基纤维素钠(CMC)经固相加热反应,制备吸附材料交联羧甲基纤维素(CCMC)。研究反应条件对CCMC交联度、交联度对CCMC吸附碱性品红(BF)和亚甲基蓝(MB)性能的影响。结果表明,酸浓度对CCMC交联度影响最大,交联度0.39的CCMC的吸附性能最佳。以交联度0.39的CCMC为吸附剂,研究吸附条件包括固液比、染料初始浓度、pH、吸附时间对CCMC吸附性能的影响。20℃,固液比0.25 g/L条件下,CCMC对BF和MB的饱和吸附量分别为570 mg/g和540 mg/g。     

交联羧甲基纤维素的制备及对染料吸附性能的研究

酸催化下,取代度0.82的羧甲基纤维素钠(CMC)经固相加热反应,制备吸附材料交联羧甲基纤维素(CCMC)。研究反应条件对CCMC交联度、交联度对CCMC吸附碱性品红(BF)和亚甲基蓝(MB)性能的影响。结果表明,酸浓度对CCMC交联度影响最大,交联度0.39的CCMC的吸附性能最佳。以交联度0.39的CCMC为吸附剂,研究吸附条件包括固液比、染料初始浓度、pH、吸附时间对CCMC吸附性能的影响。20℃,固液比0.25 g/L条件下,CCMC对BF和MB的饱和吸附量分别为570 mg/g和540 mg/g。     

壳聚糖对活性翠蓝模拟印染废水的吸附性能研究

以壳聚糖为吸附剂,研究了其对活性翠蓝模拟印染废水的吸附性能。探讨了壳聚糖用量、介质的pH值、温度、时间、染料浓度对吸附性能的影响。结果表明:壳聚糖用量增加,脱色率和吸附量逐渐减小;介质的pH在3～7范围内,吸附性能较好;温度对吸附性能影响不大;一定范围内,脱色率和吸附量随活性翠蓝浓度的增大逐渐增大。经单因素试验得出了最优工艺条件为:壳聚糖加入量为0.05g、温度为45℃、反应时间为120min、活性翠蓝溶液浓度为60mg/L、体积为50mL、介质的pH为6.9的条件下,脱色率可达到93.43%,吸附量可达到58.56mg/g。且其吸附行为符合Langmuir吸附模型。IR和SEM检测证实了壳聚糖与活性翠蓝之间的交互作用。     

采用硫因改性pHEMA膜从人体血浆中去除镉离子

我们制备了载有汽巴蓝F3GA的聚2－羟乙基异丁烯酸（pHEMA)膜并使用它从人体血浆中去除镉离子。在偶氮二异丁腈存在的情况下，通过HEMA的光聚合反应制备了pHEMA膜。然后将活性染料配位体汽巴蓝F3GA共价地附着在膜中。染料的最大负载为1.07μmol/cm^2。然后将硫因吸附在载有汽巴蓝F3GA的膜中。被吸附硫因的最大量为0.9μmol/cm^2。在汽巴蓝F3GA发生衍生作用后没有观察到pHEMA膜的水膨胀特性和接触角（水中的空气）发生变化。我们使用了这些膨胀率为58％（质量分数），载有汽巴蓝F3GA和／或硫因亲水性的膜进行了去除镉离子的研究。附着有汽巴蓝F3GA和附着有汽巴蓝F3GA／吸附有硫因的pHEMA膜从人体血浆中去除镉离子的最大量为1.7μmol。这些新型的亲和金属－缩氨酸pHEMA膜可反复用于吸附和解吸镉离子，而其吸附量没有明显的减少。     

连续进水模式下电容去离子技术除氟研究

采用连续进水模式电容去离子技术(CDI)进行除氟研究,探讨了原水质量浓度、电压、流速、pH、共存离子、离子交换膜对除氟的影响,通过动力学分析探讨了其去除机理,并考察了电极的再生性能。结果表明,在原水质量浓度为50 mg/L、电压为1.5 V、流速为7 mL/min的条件下,电极吸附量可以达到3.17 mg/g。原水质量浓度越高、电压越大,电极的吸附量就越高。撤去电压电极即可高效再生,5次循环后,电极吸附能力可保持86%。离子交换膜可有效减弱pH波动,提高电极再生性能,但吸附量降低。连续进水模式下CDI除氟过程遵循准一级动力学模型,吸附速率与剩余电容成正比。     

再生纤维素基复合纳米纤维膜的制备及其应用

采用静电纺丝技术和化学改性制备聚氨酯(PU)-偕胺肟聚丙烯腈(AOPAN)-再生纤维素(RC)复合纳米纤维膜,将其作为分离膜构建动态分离系统,并测定其对Fe~(3+)的动态吸附性能。结果表明,在液柱高度8 cm、膜层数5、Fe~(3+)的质量浓度5 mg/L的条件下,动态吸附率最高可达100%,溶液体积流量为4.60 m L/min;当Fe~(3+)的质量浓度为300 mg/L时,动态吸附数据符合Thomas和Yoon-Nelson动态吸附模型,平衡吸附量分别为117.0 mg/g和113.3mg/g。通过对复合纳米纤维膜的扫描电镜、红外光谱及拉伸力学测试表征发现,加入PU后,其断裂强力和断裂伸长率均有所提升,同时具有良好的力学性能和稳定的微观形态。     

纤维素纳米纤维膜的改性及其染料吸附性能

采用静电纺丝技术制备醋酸纤维素纳米纤维膜，用氢氧化锂水解后得到纤维素纳米纤维膜。通过3-氯-2-羟丙基三甲基氯化铵（CHPTAC）和一氯乙酸共同改性，制备了双性纤维素纳米纤维膜。利用紫外分光光度计测试双性纤维素纳米纤维膜对茜素绿（AG25）和亚甲基蓝（MB）的吸附性能，并考察了pH、温度、染料初始浓度对吸附量的影响。结果表明，双性纤维素纳米纤维膜对AG25和MB染料的最大吸附量分别达到 240 mg/g和 128 mg/g，并且对两种染料在第4个循环时仍保持84%的吸附效率。同时，发现pH是影响双性纤维素纳米纤维膜的染料吸附性能的关键因素，在吸附没有饱和之前，染料吸附量随着染料浓度的增加而增加，而吸附效果对温度没有依赖性。     

阳离子木屑纤维素的制备及其对水中2,4-二氯苯酚的吸附性能

以3-氯-2-羟丙基三甲基氯化铵(CTA)为醚化剂,对木屑纤维素(MC)进行了改性,并对产物进行了表征. 探讨了阳离子木屑纤维素用量、pH值、吸附温度、吸附时间等因素对水溶液中2,4-二氯苯酚(2,4-DCP)静态吸附效果的影响. 结果表明,阳离子木屑纤维素的制备条件为：CTA/MC质量比2.0,反应时间2.0 h,反应温度30℃,NaOH溶液浓度30%(w). 阳离子木屑纤维素对水溶液中2,4-DCP的最佳吸附条件为：pH 8.0,吸附时间90 min,吸附温度25℃. 此条件下,处理100 mL 2,4-DCP溶液(50 mg/L)的吸附率可达88.92%,吸附容量为1.482 mg/g. 木屑纤维素经改性后,对水中2,4-二氯苯酚存在化学吸附.     

Papain Adsorption on Chitosan-Coated Nylon-Based Immobilized Metal Ion (Cu2+, Ni2+, Zn2+, Co2+) Affinity Membranes

A novel immobilized metal affinity membrane was prepared for papain adsorption in this article. Higher papain adsorption capacity between 43-67 mg/g was observed and the adsorption isotherm fitted the Freundlich equation. Experimental data were analyzed using two adsorption kinetic models. The pseudo-second-order kinetic model provided better correlation to the experimental results. A significant amount of the adsorbed papain was eluted by 1.0 M NaSCN at pH 5.0 for all affinity membranes. It was concluded that the novel chitosan-coated nylon-based immobilized metal ion affinity membrane could be applied for the large-scale isolation of papain without resulting in enzyme denaturation.     

In vitro cadmium removal from human serum by Cibacron Blue F3GA–thionein‐complex conjugated affinity membranes

A new membrane affinity biosorbent carrying thionein has been developed for selective removal of cadmium ions from human serum. Microporous poly(2‐hydroxyethyl methacrylate) (pHEMA) membranes were prepared by photopolymerization of HEMA. The pseudo dye ligand Cibacron Blue F3GA (CB) was covalently immobilized on the pHEMA membranes. Then, the cysteine‐rich metallopeptide thionein was conjugated onto the CB‐immobilized membrane. The maximum amounts of CB immobilized and thionein conjugated on the membranes were 1.07 µmol cm⁻² and 0.92 µmol cm⁻², respectively. The hydrophilic pHEMA membrane had a swelling ratio of 58% (w/w) with a contact angle of 45.8 °. CB‐immobilized and CB‐immobilized–thionein‐conjugated membranes were used in the Cd(II) removal studies. Cd(II) ion adsorption appeared to reach equilibrium within 30 min and to follow a typical Langmuir adsorption isotherm. The maximum capacity (q _m) of the CB‐immobilized membranes was 0.203 (µmol Cd(II)) cm⁻² membrane and increased to 1.48 (µmol Cd(II)) cm⁻² upon CB–thionein‐complex conjugation. The pHEMA membranes retained their cadmium adsorption capacity even after 10 cycles of repeated use. © 2000 Society of Chemical Industry     

金属亲和膜色谱法纯化木瓜蛋白酶条件优化

建立了一种快速、简便的分离木瓜蛋白酶的方法。尼龙膜经壳聚糖改性后,以金属镍离子N i2+为配基制备了一种新型的蛋白质分离材料,并将该亲和膜应用于木瓜蛋白酶的分离纯化,在对洗脱液、上样速度、洗脱速度、洗脱液的pH值和洗脱液的离子强度进行优化的基础上,成功地分离纯化出木瓜蛋白酶,纯化倍数为20.59倍。     

Dye derived and metal incorporated affinity poly(2-hydroxyethyl methacrylate) membranes for use in enzyme immobilization

Microporous poly(2-hydroxyethyl methacrylate) (PHEMA) membranes were prepared by UV-initiated photopolymerization of HEMA in the presence of an initiator (α,α′-azobisisobutyronitrile, AIBN). An affinity dye Cibacron Blue F3GA (CB) was attached covalently and then Fe³⁺ ions incorporated. The PHEMA-CB and PHEMA-CB-Fe³⁺ membranes derived were used for adsorption of glucose oxidase (GOD). The adsorption capacities of these membranes were determined under conditions of different pH and with different concentrations of the adsorbate in the medium. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The glucose oxidase adsorption capacity of the Fe³⁺ incorporated membrane (87μgcm^-2) was greater than that of the dye-derived membrane (66μgcm^-2). Non-specific adsorption of the glucose oxidase on the PHEMA membranes was negligible. The K_m values for both immobilized glucose oxidase PHEMA-CB-GOD (8·3) and PHEMA-CB-Fe³⁺-GOD (7·6) were higher than that of the free enzyme (6·2mM). Optimum reaction pH was 5·5 for the free and 6·0 for both immobilized preparations. The optimum reaction temperature of the adsorbed enzymes was 5°C higher than that of the free enzyme and was significantly broader. After 15 successive uses the retained activity of the adsorbed enzyme was 87%. It was observed that enzymes could be repeatedly adsorbed and desorbed on the derived PHEMA membranes without significant loss in adsorption capacity or enzymic activity. © 1998 SCI.     

New metal chelate sorbent for albumin adsorption: Cibacron Blue F3GA-Zn(II) attached microporous poly(HEMA) membranes

Poly(2-hydroxyethyl methacrylate) [poly(HEMA)] membranes were prepared by UV-initiated photopolymerization of HEMA in the presence of an initiator (α-α′-azobis-isobutyronitrile, AIBN). The triazine dye Cibacron Blue F3GA was attached as an affinity ligand to poly(HEMA) membranes, covalently. These affinity membranes with a swelling ratio of 58% and containing 10.7 mmol Cibacron Blue F3GA/m² were used in the albumin adsorption studies. After dye-attachment, Zn(II) ions were chelated within the membranes via attached-dye molecules. Different amounts of Zn(II) ions [650–1440 mg Zn(II)/m²] were loaded on the membranes by changing the initial concentration of Zn(II) ions and pH. Bovine serum albumin (BSA) adsorption on these membranes from aqueous solutions containing different amounts of BSA at different pH was investigated in batch reactors. The nonspecific adsorption of BSA on the poly(HEMA) membranes was negligible. Cibacron Blue F3GA attachment significantly increased the BSA adsorption up to 92.1 mg BSA/m². Adsorption capacity was further increased when Zn(II) ions were attached (up to 144.8 mg BSA m²). More than 90% of the adsorbed BSA was desorbed in 1 h in the desorption medium containing 0.5M NaSCN at pH 8.0 and 0.025M EDTA at pH 4.9. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 657–664, 1998     

Fabrication of polyetherimide microporous membrane using supercritical CO2 technology and its application for affinity membrane matrix

Polyetherimide (PEI) microporous membranes with uniform cellular structure, high porosity, and narrow pore size distribution were formed by supercritical CO₂ (ScCO₂) phase inversion method, and the membrane was modified to be a matrix for the preparation of affinity membrane due to its low solvent residue and appropriate porous structure. The effects of ScCO₂ temperature and pressure on the morphology and pure water flux of the membrane were investigated. The membrane prepared at 24 MPa and 45 °C with a large mean cell diameter of 6.0 μm, high porosity of 73%, narrow pore size distribution and a pure water flux of 56 L/(m² h bar) was coated with chitosan to improve its hydrophilicity and coupled with Cibacron Blue F3GA (CB) as a special ligand to form an affinity membrane (PEI-coated chitosan-CB membrane). The PEI-coated chitosan-CB membrane showed a high adsorption capacity of 33.9 mg/g membrane to bovine serum albumin and was higher than most of affinity membranes. Moreover, the tensile strength of PEI-coated chitosan-CB membrane was 11.58 MPa and was much higher than those of affinity membranes. This work demonstrates that ScCO₂ phase inversion method is a potential method to prepare an affinity matrix.     

Nonporous monosize polymeric sorbents: Dye and metal chelate affinity separation of lysozyme

Lysozyme adsorption onto dye‐attached nonporous monosize poly(2‐hydroxyethyl‐methacrylate‐methylmethacrylate) [poly(HEMA‐MMA)] microspheres was investigated. Poly(HEMA‐MMA) microspheres were prepared by dispersion polymerization. The monochloro‐triazine dye, Cibacron Blue F3GA, was immobilized covalently as dye–ligand. These dye‐affinity microspheres were used in the lysozyme adsorption–desorption studies. The effect of initial concentration of lysozyme and medium pH on the adsorption efficiency of dye‐attached and metal‐chelated microspheres were studied in a batch reactor. Effect of Cu(II) chelation on lysozyme adsorption was also studied. The nonspecific adsorption of lysozyme on the poly(HEMA‐MMA) microspheres was 3.6 mg/g. Cibacron Blue F3GA attachment significantly increased the lysozyme adsorption up to 247.8 mg/g. Lysozyme adsorption capacity of the Cu(II) incorporated microspheres (318.9 mg/g) was greater than that of the Cibacron Blue F3GA‐attached microspheres. Significant amount of the adsorbed lysozyme (up to 97%) was desorbed in 1 h in the desorption medium containing 1.0M NaSCN at pH 8.0 and 25 mM EDTA at pH 4.9. In order to examine the effects of separation conditions on possible conformational changes of lysozyme structure, fluorescence spectrophotometry was employed. We conclude that dye‐ and metal‐chelate affinity chromatography with poly(HEMA‐MMA) microspheres can be applied for lysozyme separation without causing any significant changes and denaturation. Repeated adsorption/desorption processes showed that these novel dye‐attached monosize microspheres are suitable for lysozyme adsorption. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 115–124, 2000     

Albumin adsorption from aqueous solutions and human plasma in a packed-bed column with Cibacron Blue F3GA-Zn(II) attached poly(EGDMA-HEMA) microbeads

Affinity dye-ligand Cibacron Blue F3GA, was covalently coupled with poly(EGDMA-HEMA) microbeads via nucleophilic reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA under alkaline conditions. The microbeads carrying 16.5 μmol Cibacron Blue F3GA per gram polymer was incorporated with Zn(II) ions. Zn(II) loading was 189.6 μmol/g. Cibacron Blue F3GA-Zn(II) attached affinity sorbent was used for albumin adsorption from aqueous solutions and human plasma in a packed-bed column. BSA adsorption capacity of the microbeads decreased with an increase in the recirculation rate. High adsorption rates were observed at the beginning, then equilibrium was gradually achieved in about 60 min. The BSA concentration in the mobile phase also effected adsorption. BSA adsorption was first increased with BSA concentration, then reached a plateau which was about 128 mg BSA/g. The maximum adsorption was observed at pH 5.0 which is the isoelectric pH of BSA. Higher human serum albumin adsorption was observed from human plasma (215 mg HSA/g). High desorption ratios (over 90% of the adsorbed albumin) were achieved by using 1.0 M NaSCN (pH 8.0) in 30 min.     

Adsorption of bilirubin on poly‐L‐lysine‐containing nylon membranes: applications in affinity chromatography

Microporous polyamide membranes were activated by 1,1′‐carbonyldiimidazole (CDI) and subsequently bound with hydroxyethyl cellulose (HEC) to amplify reactive groups. Then poly‐L ‐lysine (PLL) as ligand was immobilized onto the HEC‐nylon membranes. The contents in HEC and PLL of PLL‐attached membranes were 153.2 and 63.8 mg (g nylon membrane)^?1, respectively. Such PLL‐HEC affinity membranes were used to adsorb bilirubin from bilirubin‐phosphate and bilirubin‐albumin solutions. The adsorption mechanism of bilirubin and the effects of temperature and ionic strength on adsorption were investigated by batch experiments. The results showed that the adsorption capacity increased with increasing temperature but decreased with increasing NaCl concentration, and the adsorption isotherm fitted the Freundlich model well. Dynamic experiments showed that PLL‐attached membranes can readily remove the bilirubin from bilirubin‐albumin solutions. Copyright © 2005 Society of Chemical Industry