改性聚丙烯腈超滤膜性能研究

发布时间：2018-01-16 13:11

  本文关键词：改性聚丙烯腈超滤膜性能研究　出处：《华东理工大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 聚丙烯腈超滤膜 反应改性 共混改性 表面接枝

【摘要】：超滤膜分离技术作为温和、节能、高效率的分离技术,被广泛的应用于污水处理、家庭应用水等领域。聚丙烯腈(PAN)作为易得的化工原料,有着耐候性、耐化学试剂等优良特性,但较差的机械性能和抗污染性能限制了其在水处理技术中的应用。本文主要采用PAN原料,利用非溶剂致相分离的方法制备平板超滤膜,通过反应、共混以及表面改性等方法,调控PAN膜的结构以及表面特性。通过SEM、AFM以及FTIR等方法进行微观分析,同时利用纯水通量、截留率以及接触角等对平板膜进行性能表征。采用乙醇胺(ETA)与PAN反应,制备PAN-ETA平板膜。研究反应温度和PAN浓度对平板膜结构以及性能的影响。结果表明,随着反应温度的提高以及PAN浓度的提高,铸膜液黏度逐渐增加,在凝胶浴中从瞬时分相变为延时分相,平板膜断面结构相应的从不规整的指状孔变为海绵状孔结构。通过与ETA的反应反应,PAN的平板膜的亲水性能、机械性能以及抗污染性能得到提高。当反应温度为80℃,PAN的浓度为18%时,模拟计算得到平板膜的平均孔径为4.44 nm;平板膜的纯水通量为52.72 L·m~(-2)·h~(-1),对PEG2w的截留率达到96.04%;静态接触角为49°,在0.3 g/L的BSA溶液中运行衰减率为15%,通量恢复达到90%以上;抗拉强度达到5.40 MPa,断裂伸长率为87.65%,而在PAN18T25对PEG2w的截留几乎为0;静态接触角为60°,在0.3g/L的BSA溶液中运行衰减率为37%,通量恢复仅为66%;膜抗拉强度为4.56 MPa,断裂伸长率仅为26.53%,其次通过纳米二氧化钛(Tio_2)和制备的氧化石墨烯(GO)共混改性PAN平板膜。无机粒子的共混改性能够有效的提高膜的表面孔隙率和粗糙度,提高膜的亲水性能抗污染性能。GO和纳米Tio_2都具有较强的亲水性能,能够在分相时逃逸富集在膜的分离层,使得膜形成含有不规则指状的断面和亲水性良好的表面。当GO的添加量达到0.06 g,共混温度为80℃时,断面出现指状孔,通量为63.69L·m~(-2)·h~(-1),对PEG2w的截留保持90%以上。在0.3g/L的BSA溶液中运行衰减率为11%。当Tio_2添加量为0.30g时,断面出现倒三角型的指状孔,通量提高到94.48 L.m·2·h~(-1),但是截留能力大幅下降;在BSA水溶液中运行通量衰减率为13%。最后通过聚酰胺胺(PAMAM)对PAN平板膜表面接枝,在表面形成亲水性良好的致密符合层,得到小孔径超滤膜,极大的提高膜的亲水性能和截留能力。实验结果显示在60℃环境下接枝反应4h,此时纯水通量为14.86L·m·2·h~(-1),瞬间接触角为70.5°,比M-pure降低了 10°;对PEG2k的截留率达到91.37%。
[Abstract]:As a mild, energy saving and high efficiency separation technology, ultrafiltration membrane separation technology has been widely used in sewage treatment, domestic application of water and other fields. Polyacrylonitrile (PAN) as a readily available chemical raw materials, has weathering resistance. Chemical reagents and other excellent properties, but poor mechanical properties and anti-pollution performance limits its application in water treatment technology. This paper mainly uses PAN raw materials. The flat plate ultrafiltration membrane was prepared by non-solvent phase separation method. The structure and surface properties of PAN membrane were regulated by reaction, blending and surface modification. SEM was used to prepare the membrane. The AFM and FTIR methods were used to analyze the properties of the membrane, and the pure water flux, retention rate and contact angle were used to characterize the properties of the membrane. The ethanolamine ETA-ETA was used to react with PAN. The effects of reaction temperature and PAN concentration on the structure and properties of PAN-ETA flat membrane were studied. The results showed that with the increase of reaction temperature and PAN concentration. The viscosity of casting liquid increased gradually, from instantaneous phase separation to delayed phase separation in gel bath, and the irregular finger pore into sponge pore structure corresponding to the cross-section structure of flat membrane. The reaction with ETA was carried out. The hydrophilicity, mechanical properties and antifouling properties of PAN flat membrane were improved when the reaction temperature was 80 鈩，

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