TiO_2动态改性膜应用于MBR的研究

采用二氧化钛(TiO_2)纳米粒子对聚偏氟乙烯中空纤维膜微滤膜(PVDF MF,0.1μm)和实验室自制聚砜中空纤维膜超滤膜(PSF UF,0.05μm)进行表面亲水改性,以期提高膜的抗污染能力.采用膜接触角、纯水通量、出水TOC、膜压差和扫描电子显微镜(SEM)进行表征了TiO_2动态膜的性能.将TiO_2纳米颗粒改性后的PVDF MF和PSF UF膜应用于膜生物反应器(MBR)处理模拟焦化废水(TOC=500 mg/L),考察了其对MBR过滤性能的影响.实验结果表明,改性后膜的水接触角明显减小,亲水性增强,TMP升高速率明显降低,模拟焦化废水,TOC的去除率平均可达95%,经返洗及次氯酸钠清洗后膜表面TiO_2层外观没有明显变化.改性后的膜组件较显著地增加了MBR的膜抗污染的优势,且具有一定的稳定性.因此,将TiO_2动态改性耐污染膜应用于MBR是可行的.

Study on TiO_2 dynamically modified membrane used in membrane bioreactor

In order to improve the ability of ami- pollution, the surface hydrophilic modification of polyvinylidene fluoride (PVDF) hollow fiber microfiltration (MF) membrane (PVDF MF, 0.1 μm) and laboratorymade polysulfone (PSF) hollow fiber ultrafiltration (UF) membrane (PSF UF, 0.05 μm) were investigated by the modification of TiO_2 nanoparticles. The performances of TiO_2 dynamic membranes were characterized by membrane contact angle, pure water flux, total organic carbon (TOC) in the permeate, transfer membrane pressure (TMP) and scanning electron microscope (SEM) morphology. The modified PVDF MF and PSF UF membranes were used for the membrane bioreactor (MBR) treatment of simulated coking wastewater (TOC =500 mg/L). Their filtration performances in MBR were discussed. The experimental results showed that mem brane contact angle decreased obviously, hydrophilic was enhanced and TMP increased rate was lower clearly while TOC removal ratio of simulated coking wastewater was about 95 %. After cleaning by backflushing and sodium hypochlorite, the TiO_2 dynamic membrane surface was not significantly changed. After the modification of TiO_2 nanoparticles, the membrane module increased remarkably its advantages in membrane anti - fouling and had a good stability. Therefore, TiO_2 dynamically modified anti - fouling membrane in MBR was feasible.