Washable and Reusable Zr-Metal–Organic Framework Nanostructure/Polyacrylonitrile Fibrous Mats for Catalytic Degradation of Real Chemical Warfare Agents

Abstract

The use of metal–organic frameworks (MOFs) for an efficient degradation of chemical warfare agents (CWAs) has been an active field of research over the last decade and has attracted an immense interest due to their unique properties. In particular, Zr-MOFs are known to be active for capturing CWAs and even catalyzing their hydrolysis. Here, we devised oleic acid (OA) surface-modified 140 nm sized UiO-66_NH2 nanoparticles (OA-UiO-66_NH2 NPs) with an improved dispersion in solution as compared to the conventional UiO-66_NH2 NPs. We further explored the catalytic degradation performances of OA-UiO-66_NH2 NPs for both real nerve (GD and VX) and blister (HD) agents. The hydrolysis rate was found to be more than three times faster for HD than without catalysts, and the hydrolysis conversion of GD and VX is possible up to 98 and 96.2% for 3 h, respectively. These experimental findings were completed by density functional theory calculations, which elucidated the degradation mechanism for the first time and evaluated their associated energy barriers. OA-UiO-66_NH2 NPs were demonstrated to exhibit a multi-degradation activity of both nerve agents and vesicants comparable to that of UiO-66_NH2 NPs despite the surface modification. Decisively, we successfully prepared fibrous mats by integrating a large amount of OA-UiO-66_NH2 NPs (71 wt %) into the polyacrylonitrile (PAN) polymer by electrospinning. The corresponding composite was shown to exhibit high dispersion of the MOF NPs into the polymer matrix, resulting in fine and uniform thickness of fibers. Remarkably, these fibrous mats revealed excellent reusability and stability for VX decomposition after washing five times with water. We further unraveled that OA-UiO-66_NH2/PAN fibrous mats can be processed on a large scale of utmost importance for future commercialization. These fibrous mats can be envisaged as detoxification membranes and protection clothes and incorporated into toxic gas filter masks for both military/civilian protective applications.