Feasible Detoxification Coating Material for Chemical Warfare Agents Using Poly(methyl methacrylate)-Branched Poly(ethyleneimine) Copolymer and Metal-Organic Framework Composites

Advancing Metal-Organic Framework-Based Composites for Effective Chemical Warfare Agent Detoxification under Real-World Conditions

Threats from toxic chemical warfare agents (CWAs) persist due to war and terrorist attacks, endangering both human beings and the environment. Metal-organic frameworks (MOFs), which feature ordered pore structures and excellent tunability at both metal/metal cluster nodes and organic linkers, are regarded as the best candidates to directly remove CWAs and their simulants via both physical adsorption and chemically catalyzed hydrolysis or oxidization. MOFs have attracted significant attention in the last two decades that has resulted from the rapid development of MOF-based materials in both fundamental research and real-world applications. In this review, the authors focus on the recent advancements in designing and constructing functional MOF-based materials toward CWAs detoxification and discuss how to bridge the gap between fundamental science and real-world applications. With detailed summaries from different points of view, this review provides insights into design rules for developing next-generation MOF-based materials for protection from both organophosphorus and organosulfur CWAs to mitigate potential threats from CWAs used in wars and terrorism attacks.

Printability and Performance Metrics of New-Generation Multifunctional PMMA/Antibacterial Blend Nanocomposites in MEX Additive Manufacturing

Poly(methyl methacrylate) (PMMA) is a thermoplastic widely utilized in civilian-, defense-, and medicine-related applications. Therefore, inducing antibacterial properties is an additional asset when infection control is prioritized. To counter this, PMMA was mixed, for the first time, with antibacterial agents (antibacterial blend nanopowder, AP) to curb bacterial proliferation and therefore reduce the chances of infection. The reinforcing efficacy of the blend in PMMA was also assessed. Nanocomposites were developed with various nanopowder concentrations for 3D printing material extrusion (MEX). PMMA/AP nanocomposites were evaluated for their mechanical and rheological properties, thermal stability, morphological, structural, and chemical characteristics, and bacterial resistance (against Staphylococcus aureus and Escherichia coli (E. Coli) using the well diffusion method). The effect on quality metrics, such as the geometrical accuracy and pores of the 3D-printed structure was examined with micro-computed tomography. The modified PMMA had improved properties, such as increased tensile (~20% increase at 2 wt.%) and flexural strength (~10.8% at 4 wt.%), while also having strong antibacterial properties against Staphylococcus aureus and mild antibacterial properties against E. Coli. Such improvements add to the expanding portfolio of biomaterials, such as their use in the demanding defense sector and the medical field.

A MOFs/MIPs@GAs Ternary Composite Catalytic System with Graphene Oxide Aerogels as the Multifunctional Skeleton for High-Efficiency Detoxification of Organophosphate Nerve Agents in Pure Water

Organophosphate nerve agents (OPs) are widely used as pesticides and chemical agents and pose a threat to human health and life. At present, most personal protective equipment usually only serves as physical protection and does not have an effect of chemical detoxification. In this work, ultra lightweight graphene oxide aerogels (GAs) have been used as a multifunctional skeleton to integrate the metal-organic frameworks (MOFs) and molecularly imprinted polymers (MIPs) together for obtaining a high-performance hybrid material (MOFs/MIPs@GAs) on hydrolysis detoxification of OPs. As a porous three-dimensional material full of carboxyl groups, GAs can not only support excellent mass transfer performance but also provide a proper pH self-buffering catalytic reaction external environment for hydrolyzing OPs. The obtained MOFs/MIPs@GAs can catalyze dimethyl-4-nitrophenyl phosphate (DMNP) hydrolysis detoxification rapidly in pure water (kobs = 0.2227 min-1, t1/2 = 3.11 min). This ternary hybrid material with exceptional performance and practical applicability has vast application prospects for the development of protective equipment.

Robust and highly reactive membranes for continuous disposal of chemical warfare agents: Effects of nanostructure and functionality in MOF and nanochitin aerogel composites

Developing appropriate disposal of stockpiles of chemical warfare agents (CWAs) has gained significant attention as their lethal toxicity seriously harms humanity. In this study, a novel green-fabrication method with UiO-66 catalysts and amine-functionalized chitin nanofibers (ChNFs) was suggested to prepare durable and highly reactive membranes for decomposing chemical warfare agents (CWAs) in the continuous flow system. The strong interaction between ChNFs and the UiO-66 led to stable loading of the UiO-66 on the continuous nano-porous channel of the ChNF reactive membrane even with high loading of UiO-66 (70 wt% of UiO-66 in the ChNF substrate). In addition, the Brønsted base functionalities (-NH2 and -NHCOCH3) of the ChNF enhanced the catalytic activity and recyclability of the UiO-66. The resulting 70-ChNF composites can effectively decompose a nerve agent simulant (methyl paraoxon) even after 7 repeatable cycles, which has been not obtained in the previous UiO-66 catalyst. The ChNF/UiO-66 reactive membranes with 1 m2 of the area decomposed 130 g of CWAs within an hour in a continuous flow system. We believe these robust and highly reactive membranes can provide a sustainable and efficient solution for the massive CWA disposal and also contribute to the advancement of functional membrane material science.

MIL-101-NH2(Fe)-Coated Nylon Microfibers for Immobilized Photocatalysts in RhB and Cr(VI) Removal

MIL-101-NH₂(Fe) is one of the effective photocatalytic metal-organic frameworks (MOFs) working under visible light. However, its powder-type form inhibits reusability in practical applications. In this study, we immobilized MIL-101-NH₂(Fe) on a polymeric microfiber mesh to improve reusability while minimizing the loss of catalytic performance. To overcome the lack of surface functionality of the nylon fibers, an atomic layer deposition Al₂O₃ layer and NH₂-BDC linker were introduced to facilitate uniform coating of the MOF on the fiber surface. The reactions of the metal precursor to the nylon substrate and NH₂-BDC ligand of the MOF allow chemical bonding from the core to the shell of the entire hybrid catalytic materials. The resulting fiber-immobilized MOFs (Nylon@Al₂O₃@MOF) demonstrated high photocatalytic performance in the removal of RhB and Cr(VI) as representatives of organic dyes and heavy metals, respectively, while retaining over 85% of its efficiency after five cycles.