Metalized hierarchical porous poly-melamine-formaldehyde membrane for continuous-flow reduction of 4-nitrophenol

Background Porous organic polymers (POPs) are excellent candidates for supporting and stabilizing metal nanocatalysts. The preparation of POPs monolithic membranes as carrier materials for continuous flow catalytic reactors is of significant industrial value. Methods In this work, monolithic poly-melamine-formaldehyde (ah-PMF) gel-filled membranes were prepared by filling high internal phase emulsions containing melamine and paraformaldehyde into nickel membranes with specific shapes. After in situ loading of palladium nanoparticles (Pd NPs) in ah-PMF, the composite membranes were used for the catalytic reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) under both static and continuous flow conditions. Significant findings The ah-PMF with high specific surface area and advanced hierarchical porous structure can be obtained by regulating the F127 feed, which is beneficial to improving the catalytic efficiency. The results showed that the Pd@ah-PMF composite membrane had better catalytic activity when the F127 content was 35%, especially in the continuous flow catalytic process, with 99% conversion of 10 mg/L 4-NP in 21 min. In addition, the Pd@ah-PMF showed good recyclability. This work provides a strategy for the design of carrier materials for continuous flow reactors.