聚偏氟乙烯疏水膜的制备及其膜蒸馏脱氨性能研究

Preparation of hydrophobic PVDF membrane and itsammoniaremoval performance by membrane distillation

传统膜法脱氨技术多采用相转化法制备的多孔疏水膜,由于膜孔道均匀性欠佳,导致渗透通量低、氨回收困难。采用静电纺丝技术制备具有均匀贯通孔道结构的高孔隙率聚偏氟乙烯(PVDF)纳米纤维膜,用于电厂含氨废水的膜蒸馏脱氨。分析了模拟含氨废水的pH值、温度、浓度,以及渗透测真空度对膜蒸馏脱氨性能的影响。研究发现,增大膜的厚度可延长膜的稳定运行时间,但会极大降低膜的渗透通量;提高溶液的pH值、浓度、温度及真空度均能不同程度地提高膜的脱氨性能。

Porous hydrophobic membranes used in traditional membrane distillation for deamination are usually prepared by phase conversion method.Due to the poor uniformity of pore,these membranes exhibited low permeability and nitro⁃gen recovery.Therefore,high porosity PVDF nanofiber membrane with through⁃hole structure was prepared by electro⁃spinning technology.The prepared membrane was used for the deamination of nitrogen⁃containing wastewater from power plants through membrane distillation.The effects of pH,temperature,concentration of simulated nitrogen⁃containing wastewater and osmotic vacuum on the ammonia removal performance of membrane distillation were analyzed.It was found that increasing the thickness of the membrane the stable operation time of the membrane could be prolonged,but the permeability of the membrane would be greatly reduced.Increasing the pH,concentration,temperature and vacuum degree of the solution can improve the ammonia removal capacity of the membrane in varying degrees.