磺基甜菜碱型PVDF膜在分离洗毛废水中的应用

Separation of wool scouring wastewater with sulfobetaine PVDF membrane

以甲基丙烯酸二甲氨基乙酯(DMAEMA)和甲基丙烯酸羟乙酯(HEMA)作为共聚单体,采用自由基聚合反应,成功合成了亲水性的无规共聚物poly(DMAEMA-co-HEMA)。将该共聚物添加到聚偏氟乙烯(PVDF)铸膜液中,并通过液致相转化法制备成膜,之后对膜进行后磺化反应,制得磺基甜菜碱型PVDF亲水膜。以羊毛脂乳液作为模拟洗毛废水体系,研究了羊毛脂、表面活性剂SDS质量分数,体系pH值及温度对PVDF亲水膜分离洗毛废水的影响。结果表明,洗毛废水中羊毛脂和表面活性剂十二烷基硫酸钠(SDS)质量分数越高,膜过滤时通量越低,且分离效果也会变差。洗毛废水的pH值应小于7,酸性条件下的分离效果高于碱性条件。洗毛废水温度高于40℃时,分离通量和分离效果都较好。未处理前洗毛废水的COD值为18 120 mg/L,酸沉淀、膜分离后的滤液COD值为2 002 mg/L,COD去除率达89%,通量为917 L/(m^2·h)。

In this study, a new hydrophilic random copolymer is synthesized by radical polymerization with 2-（dimethylamino） ethyl methacrylate （DMAEMA） and 2-hydroxyethyl methacrylate （HEMA） as monomers. Next, the as-prepared copolymer poly（DMAEMA-co-HEMA） is blended with poly（vinylidene fluoride） （PVDF） to fabricate membrane by non-solvent induced phase separation process. Then a new hydrophilic sulfobetaine PVDF membrane is prepared by the post-sulfonation reaction for wool scouring wastewater separation. To evaluate the performance of as-prepared sulfobetaine PVDF membrane, the effects of the lanolin concentration, surfactant （sodium dodecyl sulfate） concentration, pH value and tem- perature on the separation process are investigated taking lanolin emulsion as simulated wool scouring wastewater. The results show that, the flux and efficiency of separating wool scouring wastewater decline with the increase in lanolin concentration and surfactant （sodium dodecyl sulfate） concentration, and increase when the temperature is higher than 40 ℃. As the separation effect is better in acidic con- dition than in alkaline condition, the pH value of the wool washing wastewater should be less than 7. The COD value of the untreated wool scouring wastewater is 18 120 mg/L, and declines to 2 002 mg/L after the acid precipitation and membrane filtration. The removal rate of CODcr is 89% and the flux is 917 L/（m^2. h）.