Dibrov George, Kagramanov George, Sudin Vladislav, Grushevenko Evgenia, Yushkin Alexey, Volkov Alexey
D.Mendeleev University of Chemical Technology of Russia, 125047 Moscow, Russia.
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, 119334 Moscow, Russia.
Membranes (Basel). 2020 Nov 19;10(11):356. doi: 10.3390/membranes10110356.
This work was focused on the study of hypochlorite treatment on the pore size distribution of membranes. To this end, ultrafiltration membranes from a polysulfone/polyvinylpyrrolidone blend with a sponge-like structure were fabricated and exposed to hypochlorite solutions with different active chlorine concentrations for 4 h at ambient temperature. Liquid-liquid displacement and scanning electron microscopy were employed to study the limiting and surface pores, respectively. After treatment with 50 ppm hypochlorite solution at pH = 7.2, a five-fold increase in water permeance up to 1400 L/(m·h·bar) was observed, accompanied by a 40% increase in the limiting pore sizes and almost a three-fold increase in the porosity. After 5000 ppm treatment at pH = 11.5, a 40% rise in the maximum limiting pore size and almost a two-fold increase in the porosity and permeance was observed, whereas the mean pore size was constant. Apparently, changes in the membrane structure at pH = 11.5 were connected with polyvinylpyrrolidone (PVP) degradation and wash-out, whereas at lower pH and despite lower active chlorine concentration, this process was coupled with polysulfone (PSf) destruction and removal.
这项工作聚焦于次氯酸盐处理对膜孔径分布的研究。为此，制备了具有海绵状结构的聚砜/聚乙烯吡咯烷酮共混超滤膜，并在环境温度下将其暴露于不同活性氯浓度的次氯酸盐溶液中4小时。分别采用液-液置换法和扫描电子显微镜来研究极限孔径和表面孔径。在pH = 7.2的50 ppm次氯酸盐溶液处理后，观察到水通量增加了五倍，达到1400 L/(m·h·bar)，同时极限孔径增加了40%，孔隙率几乎增加了两倍。在pH = 11.5的5000 ppm处理后，观察到最大极限孔径增加了40%，孔隙率和通量几乎增加了两倍，而平均孔径保持不变。显然，在pH = 11.5时膜结构的变化与聚乙烯吡咯烷酮（PVP）的降解和洗脱有关，而在较低pH值下，尽管活性氯浓度较低，这个过程与聚砜（PSf）的破坏和去除有关。
