无机微滤膜分离草浆黑液中木素的机理

Mechanisms of Separating Lignin from Black Liquid by Inorganic Microfiltration

选用 5 0nm ,0 2 μm和 0 8μm的无机微滤膜 ,研究了它们对黑液中木素的截留效果 .结果表明 ,微滤膜能够有效地分离黑液中的木素 ,0 2 μmα Al2 O3 和ZrO2 膜的通量高于 5 0nm和 0 8μm膜的通量 ,当黑液SS较低时 ,随着SS浓度的增加各个微滤膜的通量急剧下降 ,当SS较高时 ,微滤膜的通量和SS浓度成线性关系 .2 g/L聚乙二醇 4 0 0 0 (PEG4 0 0 0 )溶液不会显著影响 0 2 μm和 5 0nm膜的通量 ,但却能使 0 8μm膜的通量下降 60 % 2 g/L聚乙二醇 2 0 0 0 0 (PEG2 0 0 0 0 )溶液能使各个微滤膜的通量急剧下降 .按照微滤膜污染模型的计算结果和实测被稀释黑液的粒径分布 。

The effects of rejection to lignin from black liquid were carried out by inorganic membranes which had pore size 50nm, 0.2μm and 0 8μm, respectively. The results show that MF membranes can effectively separate lignin from black liquid. The flux of 0 2μm α Al 2O 3 and ZrO 2 membranes were larger than the flux of 50nm and 0 8μm membranes. The flux of each membrane drops deeply as the SS concentration increased under the conditions of low SS in black liquid. However, the flux dropping had the linear relationship with SS concentration when it was high. 2g/L ployethylene glycol 4000 solution can not affect the fluxes of 0.2μm and 50nm membranes, effectively, instead of decreasing the flux of 0 8μm membrane about 60%. 2g/L ployethylene glycol 20000 solution can sharply decrease the flux of each membrane. Reason that provoke flux decreasing and change the rejective ability was the cake formation on the surface membrane and the lignin aggregation.