聚丙烯中空纤维膜亲水化改性及其在MBR中抗污染性的研究

发布时间：2018-04-29 13:47

本文选题：膜生物反应器 + 紫外辐照接枝　；参考：《天津工业大学》2017年硕士论文

【摘要】：膜生物反应器(MBR)在水污染治理中获得广泛的关注。膜污染、使用寿命低问题仍是制约MBR大规模推广的重要因素。这主要问题归因于膜材料强度低以及混合料液成分复杂。因此本文从膜材料出发,选择具有使用寿命长又抗污染的膜材料。本文以聚丙烯中空纤维膜为研究对象,以丙烯酸(AA)为亲水化改性主要原材料,采用连续化紫外辐照的方法接枝改性。通过控制不同的接枝反应条件,如光敏剂作用、单体浓度、卷绕速度、循环次数等因素来考察表面接枝改性的效果。通过实验发现:(1)光敏剂对接枝反应起到决定性作用,在没有添加光敏剂是接枝反应不能进行,因此没有接枝效果。(2)接枝率受单体浓度的影响显著,接枝单体浓度的升高,接枝率上升后趋于平缓,30wt.%的单体浓度作为本次接枝实验条件。(3)卷绕速度对接枝率有直接的影响,随之卷绕速度增大,接枝率先增大到减小,在3m/min时有较好的效果。(4)循环次数也对接枝率有影响,受接枝位点影响呈现先增加后趋缓的趋势。在MBR试验中对比原膜与亲水改性后膜表面及膜孔的污染行为。在恒流量11.5 L/m2h的条件下跨膜压在38-53Kpa的范围内的变化。亲水化改性后PP膜的跨膜压比原PP膜低3-5Kpa,通量恢复率高出30%。膜表观性能以及形貌变化可以由万能拉伸测试仪、场发射扫描电镜(FESEM)和原子力测试仪(AFM)来进行测试表征。膜表面和膜孔的污染物由红外光谱分析、能谱分析和激光粒径分析来完成。整个运行周期表现了亲水改性的PP膜良好的抗污染能力。设定运行条件:水力停留时间12h、污泥浓度2-6g/L、曝气量70L/min。COD和氨氮的去除率在93%和90%以上,整个污染物降解过程没有受到改性技术的影响,运行稳定。
[Abstract]:MBR (membrane Bioreactor) has been paid more and more attention in water pollution control. The problem of membrane fouling and low service life is still an important factor restricting the large-scale popularization of MBR. This problem is mainly attributed to the low strength of the membrane material and the complex composition of the mixture. In this paper, membrane materials with long service life and anti-pollution are selected. In this paper, polypropylene hollow fiber membrane was studied, and acrylic acid (AA) was used as the main material for hydrophilic modification. The graft modification was carried out by continuous ultraviolet irradiation. The effect of surface grafting modification was investigated by controlling different grafting reaction conditions such as Guang Min, monomer concentration, winding speed, cycle times and so on. It was found that the grafting reaction of Guang Min agent played a decisive role, and the grafting rate was significantly affected by the monomer concentration and the concentration of the graft monomer was increased because the grafting reaction could not be carried out without the addition of Guang Min agent. When the grafting rate increased, the monomer concentration of 30 wt.%, which was used as the condition of grafting experiment, had a direct effect on the grafting rate. With the increase of the winding speed, the grafting speed increased and the graft increased first to decrease. The number of cycles was also affected by grafting sites, and the grafting sites showed a tendency of increasing at first and then slowing down. The surface and pore fouling behaviors of the original membrane and hydrophilic modified membrane were compared in MBR test. The change of transmembrane pressure in the range of 38-53Kpa at constant flow rate of 11.5 L/m2h. The transmembrane pressure of the hydrophilic modified PP membrane was 3-5 KPA lower than that of the original PP membrane, and the flux recovery rate was 30% higher than that of the original PP membrane. The apparent properties and morphologies of the films can be characterized by universal tensile tester, field emission scanning electron microscope (FESEM) and atomic force tester (AFM). The contaminants on the membrane surface and pore were analyzed by infrared spectroscopy, energy spectrum and laser particle size analysis. The whole operation cycle showed good anti-pollution ability of hydrophilic modified PP membrane. The operating conditions were as follows: hydraulic retention time 12 h, sludge concentration 2-6 g / L, removal rate of 70L/min.COD and ammonia nitrogen above 93% and 90%, the degradation process of pollutants was not affected by modification technology, and the operation was stable.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893;X703

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