Chemical cleaning is an effective way to remove the irreversible fouling of ultrafiltration (UF) membranes. However, chemicals can also damage membranes. In order to investigate the effects of chemical cleaning on various properties of the membrane, three chemical agents, sodium hydroxide (NaOH, alkali), sodium hypochlorite (NaClO, disinfector), and citric acid (CA, acid), were used to clean polyvinylidene fluoride (PVDF) UF membranes. After two, six, and ten days of chemical cleaning, a series of changes in the physical and chemical properties proved that the structures of aged membranes were destroyed by the three agents. The aging of the membrane led to a decline in the retention performance, and the effluents were found to contain large amounts of PVDF microplastics (MPs). The concentration of PVDF MPs and the MP release rate increased rapidly with aging time. The proportion of each MP shape was fragment ˃ fiber ˃ sphere, and the proportion decreased with the increase of each MP size. The longer the aging time, the larger the proportion of small-sized MPs. Among the three agents, NaOH may be the most beneficial to the stability of ultrafiltration membrane effluent safety.

化学清洗是去除超滤 (UF) 膜不可逆污垢的有效方法。然而，化学品也会损坏膜。为了研究化学清洗对膜的各种性能的影响，使用氢氧化钠（NaOH，碱）、次氯酸钠（NaClO，消毒剂）和柠檬酸（CA，酸）三种化学试剂清洗聚偏乙烯氟化物 (PVDF) UF 膜。经过2天、6天、10天的化学清洗，物理和化学性质的一系列变化证明老化膜的结构被这三种药剂破坏了。膜的老化导致保留性能下降，并且发现流出物中含有大量PVDF微塑料（MPs）。PVDF MPs 的浓度和 MP 释放率随着老化时间迅速增加。各MP形状的比例为碎片˃纤维˃球体，随着各MP尺寸的增大，该比例逐渐减小。老化时间越长，小尺寸MP的比例越大。在三种药剂中，NaOH可能对超滤膜出水安全的稳定性最为有利。