Construction of Lewis acid-base via the formation of defective UiO-66 for regulation of the surface nanostructure on nanofiltration membrane

One of the main approaches to improve the permeability of membranes is the preparation of PA layers with nanostructures based on metal organic framework (MOF) materials. However, the interaction between MOF additives and PIP/TMC monomers and the mechanisms affecting the interfacial polymerization process have not been elucidated. In this study, the adsorption conformation between the two-phase monomers and UiO-66 (UiO-66-TFA) was established by density functional theory (DFT) calculations based on Lewis acid-base theory. The results showed that the hydrogen bonding force between UiO-66 (UiO-66-TFA) with defect structures and PIP (−199.62 kcal/mol) was significantly stronger than that between UiO-66-TFA and TMC (−26.39 kcal/mol). Moreover, two PA layers with ridged and granular morphologies were prepared by dispersing UiO-66/UiO-66-TFA in the water/organic phase to influence interfacial polymerization, using UiO-66-TFA nanoparticles as additives. Among them, the PA layers showed more pronounced morphological transformation and excellent separation properties when UiO-66-TFA was used as an additive in the aqueous phase. The representative ridge-like nanostructured nanofiltration membrane showed a pure water flux of 27.51 L·m−2·h−1 and 98.8 % retention of Na2SO4. This study provides a new idea for the preparation of PA layers with different surface nanostructures based on the IP reaction of nano-additives.