聚偏氟乙烯/聚乙烯醇膜的制备及去除毛纺印染废水中的氨氮

Preparation of PVDF/PVA blend membrane and removal of ammonia nitrogen in wool textile printing and dyeing wastewater

以聚偏氟乙烯(PVDF)、聚乙烯醇(PVA)为原料,聚乙烯吡咯烷酮(PVP)为添加剂,采用热致相分离法制备了聚偏氟乙烯共混平板膜。研究了聚乙烯醇质量分数及牵伸比对膜结构和性能的影响,并从中选取合适的膜应用于膜生物反应器(MBR)中处理毛纺印染废水。采用纳氏试剂分光光度法测定了MBR出水的氨氮质量浓度。结果表明:对于PVDF共混平板膜,PVA质量分数增加,膜的纯水通量变大。随着牵伸比的增大,膜的纯水通量先增大后减小。选用PVDF质量分数为21%、PVA质量分数为1%、添加剂PVP质量分数为3%、牵伸比为1.7和PVDF质量分数为21%、PVA质量分数为2%、添加剂PVP质量分数为3%、牵伸比为1.9的两种PVDF平板膜应用于MBR中处理毛纺印染废水,前者氨氮去除率为86.37%,后者氨氮去除率为83.65%。

Polyvinylidene fluoride(PVDF) and polyvinyl alcohol(PVA) were used as raw materials and polyvinylpyrrolidone(PVP) as additives to prepare polyvinylidene fluoride(PVDF) blend flat membrane by thermotropic phase separation. The effects of polyvinyl alcohol(PVA) mass fraction and drafting ratio on the structure and properties of the membranes were studied, and suitable membranes were selected for the treatment of wool textile printing and dyeing wastewater in membrane bioreactor(MBR). The concentration of ammonia nitrogen in MBR effluent was determined by Nessler reagent spectrophotometry. The experimental results showed that for PVDF blend flat membrane, the pure water flux increased with the increase of PVA mass fraction. With the increase of the draft ratio, the pure water flux of the membrane first increased and then decreased. Two draft PVDF membranes with PVDF mass fraction of 21%, PVA mass fraction of 1%, additive PVP mass fraction of 3%, draft ratio of1.7 and PVDF mass fraction of 21%, PVA mass fraction of 2%, additive PVP mass fraction of 3% and draft ratio of1.9 were used to treat wool textile printing and dyeing wastewater in MBR. The ammonia nitrogen removal rate of the former was 86.37%, and the ammonia nitrogen removal rate of the latter was 83.65%.