Highly catalytic and durable nanocellulose fibers-based nanoporous membrane film for efficient organic pollutant degradation

Sulfate radical-based advanced oxidation processes (SR-AOPs) have received significant attention because of the efficient and non-selective degradation of organic pollutants during water purification. Metal-organic frameworks (MOFs) are considered a promising catalyst for efficiently activating the oxidant in SR-AOPs to generate radicals such as SO4·− and ·OH due to the large specific surface area and highly exposed active metal ions of MOFs. However, the natural characteristics, such as small-sized particles (micro or nano), brittleness, low density, and easy aggregation, limit using powdery MOFs in practical applications requiring recyclability. This study proposes a facile method to fabricate ZIF-67@cellulose nanofibril (CNF)-based catalytic hybrid membranes and their water purification by the peroxymonosulfate (PMS) activation. The chemical structure and surface morphology of membranes were investigated, indicating that CNFs immobilize the MOF nanoparticles to form a stable and porous two-dimensional membrane. Additionally, the catalytic membrane embedding ZIF-67 nanoparticles was reusable after wastewater treatments. The ZIF-67@CNFs hybrid membrane activated PMS to produce SO4·− and ·OH radicals. Thereafter, highly active radicals efficiently degraded approximately 98.7 % of the organic dye Rhodamine B within 10 min. These findings imply that MOFs can be hybridized with nanocellulose fibers for high-performance catalytic membranes for water remediation.