Continuous Flow Composite Membrane Catalysts for Efficient Decomposition of Chemical Warfare Agent Simulants.

Continuous and safe decomposition of chemical warfare agents (CWAs) is the critical issue to protect both soldier and citizen, and to eliminate its stockpiles after cold war. The Zr-based metal-organic framework (Zr-MOF) has been known the most effective catalyst to decompose CWAs, especially the most fatal nerve agents, however its low processability due to powder form and insufficient stability limits to expand to actual military applications. To this end, the composite membrane catalysts (CMCs) comprising of Zr-MOF (UiO-66 catalyst) and nylon 6 nanofiber (porous supporter) are developed by the simple integration of electrospray and electrospinning, resulting in selective immobilization of UiO-66 on the surface of the nylon 6 nanofibers. These strategical benefits of CMCs gave super catalytic durability including recyclability over 5 times without decreasing the catalytic activity for the decomposition of methyl paraoxon (MPO), a simulant of nerve agent, in the presence of N-ethyl morpholine (N-EM), which was not achieved in the original particulate UiO-66. Due to the excellent physical and chemical stabilities of CMCs, CMC with 56 wt% of UiO-66 (CMC56) decomposed 198 g of MPO within an hour in the continuous flow system with 21.6 mL h-1 of the flow rate. This study highlights the important strategies in designing the feasible membrane-type catalysts with superior catalytic activity and robust durability to decompose chemical warfare agents in the continuous flow system.