二氧化钛动态膜在油水乳化液分离中的应用研究

Application of TiO_2 Dynamic Membrane in Separation of Oil-in-water Emulsions

以多孔管式炭膜为载体制备二氧化钛动态膜并开展动态膜分离油水乳化液的研究,考察了载体孔径对动态膜的截留率和稳定渗透通量的影响。实验结果表明,动态膜处理油水乳化液的截留率在98%以上,渗透液浓度低于8.3mg·L-1,达到国家环保排放要求;稳定渗透通量随载体孔径的增大先减小后增大。在实验基础上,提出了动态膜稳定渗透通量衰减率(FDR)的概念,并将FDR的变化趋势与动态膜类型进行关联研究。分析发现,FDR随载体孔径的增大先增大后减小,动态膜由完全堵塞过滤型过渡为中间堵塞过滤型;用中间堵塞过滤型动态膜过滤油水乳化液时,随着载体孔径的增大,渗透通量衰减变缓。

Titanium dioxide dynamic membranes （DM） were formed on carbon tube support via crossflow microfiltration, and their performances in separation of oil-in-water emulsions were experimentally studied. The effects of pore size of the support on oil rejection efficiency and steady permeate flux were examined. Results show that oil rejection efficiency of the prepared DM is higher than 98% and oil concentration of permeate solution is less than 8.3 mg.L-1, which meets the requirement of national drainage control regulations. The steady permeate flux increases at first then decreases with the increase of the support pore size. A novel concept, ＂steady flux decay ratio＂ （FDR） of DM was proposed, and types of DM were identified based on the concept. Analysis displays that the FDR increases at first then decreases with the increase of the support pore size, and microfiltration type of DM transits from full blocking filtration to intermediate blocking filtration during which the decline of permeate flux becomes slower as the support pore size is increased.