The cleaning efficiency of salt cleaning and osmotic backwash in a nanofiltration (NF) process is evaluated using model organic foulants in the presence of calcium ions (Ca²⁺). In particular, the organic fouling behavior—which depends on Ca²⁺ concentration—and cleaning mechanism in both salt cleaning and osmotic backwash are studied. The results show that Ca²⁺ aggravates organic fouling, and the fouling formation rate is affected by the Ca²⁺/foulant ratio. Salt cleaning and osmotic backwash effectively clean Ca²⁺-bridging fouling, and the important cleaning mechanism in both methods is ion-exchange between the monovalent and divalent cations, resulting in the breakup of Ca²⁺–foulant binding and Ca²⁺-induced intermolecular bridging. The cleaning efficiency of osmotic backwash is 26% higher than that of salt cleaning, primarily owing to that the backwash flux creates synergy effect with ion-exchange to removes the weakened fouling structure on the membrane surface. In addition, the cleaning efficiency for irreversible fouling is of the order of osmotic backwash > chemical cleaning > salt cleaning, and osmotic backwash exhibited a 7.3% and 20.8% higher cleaning efficiency than chemical cleaning and salt cleaning, respectively. Therefore, osmotic backwash can stably maintain NF membrane performance for organic fouling and potentially replace the traditional chemical cleaning.

在钙离子（Ca ²⁺）存在的情况下，使用模型有机污垢剂评估了纳滤（NF）过程中盐清洁和渗透反冲洗的清洁效率。特别是，研究了有机污垢行为（取决于Ca ²⁺浓度）以及盐净化和渗透反洗中的净化机理。结果表明，Ca ²⁺加剧了有机结垢，并且结垢形成速率受Ca ²⁺ /结垢率的影响。盐清洗和渗透反冲洗可有效清除Ca ²⁺桥接污垢，两种方法中的重要清洗机理是单价和二价阳离子之间的离子交换，从而导致Ca ²⁺分解。-污垢结合和Ca ²⁺诱导的分子间桥联。渗透反冲洗的清洗效率比盐清洗高26％，这主要是因为反冲洗助焊剂与离子交换产生协同作用，从而去除了膜表面上的结垢结构。此外，不可逆结垢的清洗效率约为渗透反冲洗>化学清洗>盐清洗，而渗透反冲洗的清洗效率分别比化学清洗和盐清洗高7.3％和20.8％。因此，渗透反冲洗可以稳定地保持NF膜对有机污垢的性能，并有可能替代传统的化学清洁方法。