The separation behaviour and mass transfer mechanism of salicylic acid (SA) and two phenols by a polymer inclusion membrane (PN-PIM) based on polyvinyl chloride (PVC) as a base polymer and N,N-bis (1-methylheptanyl) acetamide (N503) as a carrier were studied. The correlation between the effects of carrier content and membrane thickness on the morphology, structure and mass transfer stability of PN-PIM was discussed. PN-PIM presented a good mass transfer capability for SA and p-nitrophenol (PNP) through a hydrogen transfer mechanism in weakly acidic environments and with low-concentration NaOH as a stripping phase. The mass transfer rate was in accordance with the first-order kinetic equation. At pH 6, the phenol and PNP coexisting with SA can be selectively removed. The mass transfer of PNP in PN-PIM was consistent with the diffusion mechanism, whereas that of SA exhibited the characteristics of a fixed-site hopping mechanism. When the carrier content was 68.8 %, the permeability coefficient (P) of PNP and SA reached at 9.02 and 8.74 μm/s, respectively. The mass transfer activation energies of PNP and SA totalled 13.23 and 19.08 kJ/mol, respectively. Moreover, intramembrane diffusion was the main controlling step of the mass transfer of PNP and SA in PN-PIM. Given the dual effects of PN-PIM membrane thickness on mass transfer stability and mass transfer rate, the suitable thickness range of PN-PIM was 160–180 μm.

水杨酸（SA）和两种酚通过基于聚氯乙烯（PVC）和N，N的聚合物包合膜（PN-PIM）的分离行为和传质机理研究了以双（1-甲基庚基）乙酰胺（N503）为载体。讨论了载流子含量和膜厚度对PN-PIM的形貌，结构和传质稳定性的影响。PN-PIM通过弱酸性环境中的氢转移机理以及低浓度的NaOH汽提相，对SA和对硝基苯酚（PNP）表现出良好的传质能力。传质速率符合一阶动力学方程。在pH值为6时，可以选择性地除去与SA共存的苯酚和PNP。PN-PIM中PNP的传质与扩散机制一致，而SA的PNP则表现出固定位跳跃机制的特征。当载体含量为68.8％时，PNP和SA的渗透系数（P）达到9.02和8。分别为74μm/ s。PNP和SA的传质活化能分别为13.23和19.08 kJ / mol。此外，膜内扩散是PN-PIM中PNP和SA传质的主要控制步骤。考虑到PN-PIM膜厚度对传质稳定性和传质速率的双重影响，PN-PIM的合适厚度范围为160-180μm。