Aminosilane modification of MOF-74 improves the organic solvent nanofiltration performance of AS-MOF-74 (M)/P84 composite membrane

In the field of organic solvent nanofiltration (OSN), achieving high perm-selectivity and resistance to harsh solvents remains a critical challenge. This study investigates the eco-friendly synthesis of MOF-74(M) nanoparticles (M = Ni, Zn) embedded within a P84 matrix to examine how metal cluster variation influences the OSN performance of mixed-matrix composite membranes (MMCMs). To enhance compatibility, dispersion, stability, and overall membrane performance, the MOF-74(M) nanoparticles were functionalized with 3-aminopropyl triethoxysilane (APTES) and incorporated into P84 at various concentrations (1, 3, 5, and 7 wt%). Among the different loadings of aminosilane-functionalized MOF nanoparticles, MMCMs with 5 wt% filler loading achieved optimal performance. These MMCMs demonstrated exceptional Congo Red (CR) rejection (>96%) with ethanol permeance values of 65 and 58 L m⁻2 h⁻1 bar⁻1 for MNi-AS and MZn-AS, respectively. The impressive OSN performance is attributed to the improved interfacial contact and effective dispersion of the filler within the P84 matrix. Additionally, the MMCMs showed excellent chemical stability, retaining over 95% of their weight after exposure to harsh solvents such as DMSO and NMP through a simple and mild in-situ crosslinking process. Both MNi-AS and MZn-AS also exhibited stable performance in long-term CR/ethanol filtration, underscoring their potential in OSN applications and providing valuable insights for future membrane design. [Display omitted] •Eco-friendly synthesis of MOF-74(M) and aminosilane modified AS-MOF-74(M).•The effect of metal cluster and crosslinking on the OSN performance of MMCMs.•The MMCMs exhibited high solvent permeance and efficient dye rejection capabilities.•The MMCMs exhibited good antifouling, and long-term stability.