超滤膜材料对SiO_2-有机物膜污染行为的影响

The effect of ultrafiltration membrane materials on the combined fouling behavior of SiO_2-organic coexist foulants

选用聚偏氟乙烯(PVDF)及乙烯乙烯醇共聚物(EVOH)2种超滤膜,针对SiO_2–牛血清蛋白(BSA)及SiO_2–腐殖酸(HA)2种无机–有机混合污染物,通过单种及混合污染物过滤实验,结合各污染物与膜之间作用力的测定,考察膜材料对SiO_2–有机混合污染物膜污染行为的影响机制.结果表明:与单种有机污染物HA或BSA相比,SiO_2–HA/BSA混合污染物对PVDF及EVOH超滤膜的污染会出现加剧和减缓2种相反的现象.结合作用力结果发现:当膜–SiO_2之间的作用力大于膜–有机污染物之间作用力时,与单种有机污染物相比,SiO_2的存在会加剧膜污染;相反,当膜–SiO_2之间作用力小于膜–有机污染物之间作用力时,SiO_2的存在会有效减缓膜污染.上述结果说明膜材料是控制无机–有机混合污染物膜污染行为的关键因素.

In this study, for better understanding the effect mechanism of ultrafiltration (UF) membrane materials on the combined fouling behavior of SiO 2-organic coexist foulants, two typical UF membranes-poly (vinylidene fluoride)(PVDF) and poly (ethylene-co-vinyl alcohol)(EVOH) were used. For the SiO 2-humic acid (HA) and SiO 2-bovine serum albumin (BSA) combined systems, the fouling experiments with single and combined foulants were carried out with PVDF and EVOH membranes, and the interaction forces between each foulant and membrane were investigated. The results indicated that, compared with HA or BSA, the SiO 2-HA/BSA combined foulants led to two opposite fouling phenomena for PVDF and EVOH membranes, i.e. combined fouling was enhanced or mitigated. Combined with the results of interaction forces, it was easy to find that, for the SiO 2-organic combined system, when the SiO 2-membrane interaction force was stronger than the organic-membrane interaction force, the membrane fouling would be enhanced with the addition of inorganic SiO 2 particles. In contrast, when the interaction force between SiO 2 and membrane was weaker than that between organic and membrane, the membrane fouling would be mitigated with the addition of inorganic SiO 2 particles. All these suggested that membrane material was close related to the combined fouling behavior of inorganic-organic foulants.