水中Fe^(3+)与蛋白质共存时膜污染机理

Effect of metal ions on the protein fouling of PVDF ultrafiltration membranes

利用牛血清蛋白(BSA)与FeCl_3等配制的混合溶液模拟污水进行膜过滤实验,研究超滤膜中金属离子铁(Fe^(3+))与蛋白质(BSA)共存时对膜污染的影响。研究发现,在pH为3时,向BSA混合溶液中添加Fe^(3+)会在一定程度上影响其对膜的污染程度.BSA与Fe^(3+)之间存在静电相互作用从而形成胶体态物质是其产生影响的原因之一,在相同BSA浓度下,随着FeCl_3浓度的增加,当FeCl_3质量浓度达到20mg/L时,膜污染最为严重.而在相同BSA与FeCl_3浓度条件下,随着pH的增加,当pH为7时,膜污染最严重,这是由于此时BSA带负电,被带正电的铁离子沉淀层所吸附,在膜表面形成BSA/铁的聚合物.

The effects of the Fe（ Ⅲ ） ions coexisting with protein on the fouling of ultrafiltration membranes were studied wtih the mixed solusion of BSA（bovine serum albumin） of FeCl3 as simalated wastewater. The results show that the addition of Fe3＋ into the BSA solution would cause more severe fouling at pH 3. And, at the same BSA concentration, the membrane flux declined sharply with 20 mg/L FeC13. However, membrane fouling became more severely with pH increasing, the flux decline of the membrane was highest at pH 7. Because the BSA was adsorbed by the positively charged iron precipitate layer, which can easily interacted with Fe3＋ and ferric compounds. Therefore, BSA/iron can more easily deposited onto the surface of the membrane.