Advances in Metal–Organic Frameworks for the Removal of Chemical Warfare Agents: Insights into Hydrolysis and Oxidation Reaction Mechanisms

Abstract

The destruction of chemical warfare agents (CWAs) is a crucial area of research due to the ongoing evolution of toxic chemicals. Metal–organic frameworks (MOFs), a class of porous crystalline solids, have emerged as promising materials for this purpose. Their remarkable porosity and large surface areas enable superior adsorption, reactivity, and catalytic abilities, making them ideal for capturing and decomposing target species. Moreover, the tunable networks of MOFs allow customization of their chemical functionalities, making them practicable in personal protective equipment and adjustable to dynamic environments. This review paper focuses on experimental and computational studies investigating the removal of CWAs by MOFs, specifically emphasizing the removal of nerve agents (GB, GD, and VX) via hydrolysis and sulfur mustard (HD) via selective photooxidation. Among the different MOFs, zirconium-based MOFs exhibit extraordinary structural stability and reusability, rendering them the most promising materials for the hydrolytic and photooxidative degradation of CWAs. Accordingly, this work primarily concentrates on exploring the intrinsic catalytic reaction mechanisms in Zr-MOFs through first-principles approximations, as well as the design of efficient degradation strategies in the aqueous and solid phases through the establishment of Zr-MOF structure–property relationships. Recent progress in the tuning and functionalization of MOFs is also examined, aiming to enhance practical CWA removal under realistic battlefield conditions. By providing a comprehensive overview of experimental findings and computational insights, this review paper contributes to the advancement of MOF-based strategies for the destruction of CWAs and highlights the potential of these materials to address the challenges associated with chemical warfare.

A Miniaturized Method for Evaluating the Dynamic Gas-Phase Adsorption and Degradation of Sarin on Porous Adsorbents at Different Humidity Levels

“…This is consistent with a type V isotherm under the IUPAC classification. It was further argued that this type V behavior would be more advantageous than strongly hydrophilic (Type I) or hydrophobic (type III) behavior . In light of our results, the indications that uptake increased with RH is very interesting.…”

“…Accordingly, an earlier study showed that solid-phase hydrolysis rates are much lower than those in buffer solutions and that raising the water content of NU-1000 from 0 to 400% only slightly increased the hydrolysis rate of the simulant dimethyl 4-nitrophenyl phosphate . Several recent reviews have highlighted the importance of both water and a suitable base in solid-state hydrolysis; ,, even if an OP-agent effectively binds to a hydrated Zr-node and HF is eliminated after nucleophilic attack, a base may still be important for removal of the hydrolysis product. Further, if the hydrolysis product has a high binding energy, the hydrolytic reaction may become stoichiometric rather than catalytic .…”