改性PES膜在MBR中膜阻力分析及膜污染机理研究

以聚醚砜(PES)、醋酸纤维素(CA)和纳米二氧化钛(TiO2)为膜材料,采用L-S相转化法制备共混改性PES膜。在24℃、0.2 MPa的操作条件下,制得的PES膜纯水通量为300 L/(m2.h)左右,CA改性PES膜为660 L/(m2.h)左右,TiO2改性PES膜为840 L/(m2.h)左右。通过膜生物反应器中膜阻力的测定,表明膜污染主要由浓差极化层及凝胶层引起的;通过活性污泥对膜污染机理的研究,判断出污泥的过滤过程基本符合沉积过滤定律。在MBR中运行时,改性PES膜稳定通量高于未改性膜,总阻力低于未改性膜;TiO2改性膜稳定通量高于CA改性膜,总阻力低于CA改性膜;通过扫描电镜分析,改性PES膜沉积层的厚度均比未改性膜薄,TiO2改性膜沉积层厚度小于CA改性膜,表明改性膜的抗污染性能提高了,TiO改性膜抗污染性能更优。

Membrane resistance analysis and research on membrane fouling mechanism of modified PES membrane in membrane bioreactor

The modified polyethersulfone(PES) membrane was prepared by L-S phase inversion method with cellulose acetate(CA) and TiO_2 as membrane materials.The water flux of PES membrane was nearly 300 L/membrane modified by TiO_2,under the operational conditions of 24 ℃=and 0.2 MPa.The membrane resistance determination in a membrane bioreactor was found that membrane fouling was mainly due to concentration polarization layer and gel layer.The membrane fouling mechanism studied by activated sludge was judged that sludge filtration process basically accorded with the deposition filtration law.When membranes were used in the MBR,the stable flux of modified PES membrane was higher than that of the unmodified and the total resistance was lower;the stable flux of membrane modified by TiO_2 was higher than that of membrane modified by CA and the total resistance was lower.Scanning electron microscopy analysis indicated that the deposition layer thickness of modifled membrane was thinner than that of the unmodified.the deposition layer thickness of membrane modified by TiO_2,was thinner than that of membrane modified by CA,which showed the anti-pollution performance of modified membrane was improved,and the anti-pollution performance of membrane modified by TiO_2 was even more excellent.