聚乙烯醇微球抗污染动态膜的制备及性能

Fabrication and performance of polyvinyl alcohol micro-sphere anti-fouling dynamic membrane

采用静电自组装和过滤预涂技术将表面富含羟基、具有强亲水性和电负性的聚乙烯醇微球(polyvinyl alcohol micro-sphere,PVA-MS)与工业滤布基膜相结合,分别制备无滤饼标准型和完全堵塞型PVA-MS动态膜。对膜的表征和性能的对比研究表明,PVA-MS组成的动态膜结构能明显改善基膜的亲水性、负电性。自组装PVA-MS动态膜的有效过滤孔径为2.1μm,清水阻力为1.02×1010m-1,对基膜的截留性能基本没有提高,预涂PVA-MS动态膜的有效过滤孔径为0.4μm,清水阻力为1.07×1011m-1,对浊度为21.34NTU和TOC为18.3mg·L-1的上清液过滤出水为0.23NTU和9.4mg·L-1,分别提高基膜截留效果20%和30%。动态膜不可逆污染的去除性能研究表明,自组装PVA-MS动态膜在化学清洗后能保持大部分PVA-MS的存在,预涂PVA-MS动态膜利用物理反冲洗可完全去除不可逆膜污染,再预涂后即再生。

Polyvinyl alcohol micro-sphere （PVA-MS） was prepared from PVA and glutaraldehyde after emulsification and cross linking with hemiacetal. FTIR analysis and zeta potential indicated presence of several hydroxy groups and electronegativity. Two PVA-MS dynamic membranes （DMs） of standard blockage filtration type without filter cake and full blockage filtration type were prepared from industrial filter cloth substrate membrane by using self-assembly coating （SA） and pre-coating （PC） methods, and the PVA-MS densities of the self-assembly coating dynamic membrane （SADM） and pre-coating dynamic membrane （PCDM） were determined to be 2.25 g ~ m^-2 and 62.0 g · m^-2, respectively, and their retention particle diameters were 2.1 μm and 0.4 μm respectively. PVA-MS DMs could improve hydrophilicity and negative charge of the filter cloth substrate membrane significantly. The PCDM rejection abilities for the sludge supernatant with turbidity 21.34 NTU and TOC 18.3 mg·L^-1 were improved by 20% and 30% respectively as compared with the substrate membrane. But, SADM had little impact on the rejection of turbidity and TOC. The efficiency of physical cleaning for the irreversible membrane fouling would increase with increasing coated MS on the filter cloth. SADM could be maintained on the filter cloth even after frequent chemical cleaning; however, regarding the PCDM, physical cleaning could eliminate the irreversible fouling completely, but a repeated precoating was needed to maintain the MS layer on the surface of the filter cloth.