静电纺丝纳米纤维膜固定化酶及去除水体污染的性能研究

发布时间：2018-12-13 11:46

【摘要】：水维持着地球上一切生物的生存,水也是人类发展的必要条件。伴随当今迅猛发展的经济,不断增长的人口,水资源遭受的污染越来越严重,使得水资源的供需更为紧迫。污染中尤以含酚废水最为常见,它危害大且污染范围广,酚类是公认的可致癌物,残留在水体中的高浓度的酚类物质对人类、动物和植物有着直接的危害。因此,绿色、高效处理含酚废水技术已成为各国政府和科学家亟需解决的难题。相比于其他处理技术,生物酶作为一种高效催化剂,可以直接作用于污染物质的化学链,将其降解,具有条件温和、高效、成本低和无毒副产物等优点,逐渐成为水体污染处理应用与研究的热点。本文采用静电纺丝技术制备多孔聚苯乙烯纳米纤维膜,并作为载体固定辣根过氧化物酶(HRP),用于处理酚类废水。重点研究了静电纺丝参数对纤维形貌的影响;固定化HRP酶条件对酶活性的影响;以及固定化HRP处理含酚废水的性能。本项目的研究对研制新型酶固定化载体材料和创新污水处理技术具有重要的意义。本论文主要做了以下几个方面的研究工作:(1)研究了静电纺丝技术制备聚苯乙烯纳米纤维膜及其最佳纺丝工艺。为了获得出丝效果最好,纤维形貌最佳的电纺聚苯乙烯纳米纤维膜,本论文对静电纺丝的制备条件进行研究。通过对电纺条件、溶质浓度和溶剂种类及配比等影响纤维形貌的参数进行优化,获得了最佳纤维膜的电纺条件:聚苯乙烯浓度为15%(wt),溶剂(N,N-二甲基甲酰胺(DMF):四氢呋喃(THF))配比为50:50(体积比),电压16 k V,接收距离为15 cm。(2)研究了电纺聚苯乙烯纳米纤维固定化HRP酶及其最佳固定化参数。采用表面偶联吸附方法在改性后的聚苯乙烯纳米纤维表面固定辣根过氧化物酶(HRP)。研究了固定化时间、酶溶液浓度和PH参数对固定化HRP酶活的影响,结果表明最佳固定化HRP酶的条件为:固定时间为240 min、PH 7.0、酶浓度为200 U/L。更进一步的研究表明,经过固定化的HRP酶相比于自由酶,放置稳定性和PH稳定性均得到显著提高。(3)研究了固定化HRP酶处理苯酚的性能及条件优化。论文对比研究了聚苯乙烯纳米纤维膜的纯物理吸附、自由酶以及聚苯乙烯纳米纤维膜固定化酶对苯酚的处理效果。结果表明固定化酶对苯酚的处理效果显著高于膜的物理吸附和自由酶的催化,更进一步的对固定化酶处理苯酚的最适条件进行了考察,在固定化酶用量为0.25 mg/g,苯酚浓度为75mg/L,过氧化氢和苯酚摩尔比为1:1时的苯酚去除率最高。
[Abstract]:Water sustains the existence of all living things on the earth, and it is also a necessary condition for human development. With the rapid development of economy and increasing population, the pollution of water resources is becoming more and more serious, which makes the supply and demand of water resources more urgent. Phenolic wastewater is the most common pollution, which is harmful and has a wide range of pollution. Phenols are recognized as carcinogens, and high concentrations of phenols residues in water have direct harm to human beings, animals and plants. Therefore, green and efficient treatment of phenolic wastewater has become a difficult problem for governments and scientists. Compared with other treatment techniques, biological enzymes, as an efficient catalyst, can directly act on the chemical chain of pollutants and degrade them, which have the advantages of mild conditions, high efficiency, low cost and non-toxic by-products. It has gradually become a hot spot in the application and research of water pollution treatment. In this paper, porous polystyrene nanofiber membrane was prepared by electrospinning technique and used as carrier to immobilize horseradish peroxidase (HRP),) to treat phenolic wastewater. The effects of electrospinning parameters on fiber morphology, the effect of immobilized HRP enzyme conditions on the enzyme activity, and the performance of immobilized HRP in the treatment of phenolic wastewater were studied. The research of this project is of great significance to the development of new enzyme immobilized carrier materials and the innovation of wastewater treatment technology. The main work of this thesis is as follows: (1) the preparation of polystyrene nanofiber membrane by electrostatic spinning and its optimum spinning process are studied. The preparation conditions of electrospun polystyrene nanofibers were studied in this paper in order to obtain the best spinning effect and the best fiber morphology. By optimizing the parameters affecting fiber morphology, such as electrospinning condition, solute concentration, solvent type and ratio, the optimum electrospinning conditions of fiber membrane were obtained as follows: the concentration of polystyrene was 15% (wt), solvent (N. The immobilization of HRP enzyme by electrospun polystyrene nanofibers and its optimum immobilization parameters were studied by using N-dimethylformamide (DMF): tetrahydrofuran (THF) at 50:50 (volume ratio), voltage of 16 kV and receiving distance of 15 cm. (2). Immobilization of horseradish peroxidase (HRP). On the surface of modified polystyrene nanofibers by surface coupling adsorption The effects of immobilization time, concentration of enzyme solution and PH parameters on the activity of immobilized HRP were studied. The results showed that the optimal conditions for immobilization of HRP were as follows: immobilization time was 240 min,PH 7.0, enzyme concentration was 200 UL. Further studies showed that the stability of the immobilized HRP enzyme was significantly higher than that of the free enzyme. (3) the properties and conditions of the immobilized HRP enzyme for phenol treatment were studied. In this paper, the effects of pure physical adsorption, free enzyme and immobilized enzyme on phenol of polystyrene nanofiber membrane were studied. The results showed that the effect of immobilized enzyme on phenol treatment was significantly higher than that on membrane physical adsorption and free enzyme catalysis. The optimum conditions of immobilized enzyme for phenol treatment were further investigated. The amount of immobilized enzyme was 0.25 mg/g,. When phenol concentration is 75 mg / L, the removal rate of phenol is the highest when the molar ratio of hydrogen peroxide to phenol is 1:1.
【学位授予单位】：大连海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O629.8;X52

【参考文献】