Preparation of highly efficient nanofiltration membranes resistant to organic solvents by adjusting zinc oxide nanoparticle-loaded attapulgite

Abstract

Zinc oxide nanoparticle-loaded attapulgite was successfully added to the polyamide layer for the preparation of high-efficiency organic solvent nanofiltration membranes. The addition of zinc oxide nanoparticle-loaded attapulgite to the aqueous monomer regulates the diffusion rate of interfacial polymerization, generating a thin and loosely packed polyamide layer. In addition, the abundant hydrophilicity of the nanoparticles lays the foundation for increased polar solvent permeation. The organic solvent nanofiltration membrane with the best performance exhibited an optimum methanol permeability of 13.19 L m−2h−1 bar−1, which was 1.54 times higher than that of the unadded membrane. Meanwhile, the optimum membrane consistently rejected more than 99.40 % of Evans blue dye, and the rejection rates of different dyes were consistent with the size-sieving effect. Furthermore, the permeation capacities of the membranes were evaluated using organic solvents with different polarities, viscosities, and molecular diameters, and the permeability of acetonitrile reached 16.98 L m−2h−1 bar−1. In addition, the optimum membranes retained excellent rejection capacity after soaking in the strongly polar solvent N, N-dimethylformamide (DMF) for 10 days at room temperature.