Search Results (10)

Mustard gas (HD) is a well-known chemical warfare agent, recognized for its extreme toxicity and severe hazards. Metal–organic frameworks (MOFs), with their unique structural properties, show significant potential for HD adsorption applications. Due to the extreme hazards of HD, most experimental studies focus on its simulants, but molecular simulation research on these simulants remains limited. Simulation analyses of simulants can uncover structure–performance relationships and enable experimental validation, optimizing methods, and improving material design and performance predictions. This study integrates molecular simulations, machine learning (ML), and molecular fingerprinting (MFs) to identify MOFs with high adsorption performance for the HD simulant diethyl sulfide (DES), followed by in-depth structural analysis and comparison. First, MOFs are categorized into Top, Middle, and Bottom materials based on their adsorption efficiency. Univariate analysis, machine learning, and molecular fingerprinting are then used to identify and compare the distinguishing features and fingerprints of each category. Univariate analysis helps identify the optimal structural ranges of Top and Bottom materials, providing a reference for initial material screening. Machine learning feature importance analysis, combined with SHAP methods, identifies the key features that most significantly influence model predictions across categories, offering valuable insights for future material design. Molecular fingerprint analysis reveals critical fingerprint combinations, showing that adsorption performance is optimized when features such as metal oxides, nitrogen-containing heterocycles, six-membered rings, and C=C double bonds co-exist. The integrated analysis using HTCS, ML, and MFs provides new perspectives for designing high-performance MOFs and demonstrates significant potential for developing materials for the adsorption of CWAs and their simulants. Full article

We report the exfoliation of ultrathin gallium oxide (Ga₂O₃) films from liquid metal balloons, formed by injecting air into droplets of eutectic gallium–indium alloy (eGaIn). These Ga₂O₃ films enable the selective adsorption of carbon nanotubes (CNTs) dispersed in water, resulting in the formation of a dense, percolating CNT network on their surface. The self-assembled CNT network on Ga₂O₃ provides a versatile platform for device fabrication. As an example application, we fabricated a chemiresistive gas sensor for detecting simulants of chemical warfare agents (CWAs), including diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), and triethyl phosphate (TEP). The sensor exhibited reversible responses, high sensitivity, and low limits of detection (13 ppb for DIMP, 28 ppb for DMMP, and 53 ppb for TEP). These findings highlight the potential of Ga₂O₃ films derived from liquid metal balloons for integrating CNTs into functional electronic devices. Full article

Activated carbon fibers (ACFs) derived from various polymeric fibers with the characteristics of a high specific surface area, developed pore structure, and good flexibility are promising for the new generation of chemical protection clothing. In this paper, a polyacrylonitrile-based ACF felt was prepared via the process of liquid phase pre-oxidation, along with a one-step carbonization and chemical activation method. The obtained ACF felt exhibited a large specific surface area of 2219.48 m²/g and pore volume of 1.168 cm³/g, as well as abundant polar groups on the surface. Owing to the developed pore structure and elaborated surface chemical property, the ACF felt possessed an intriguing adsorption performance for a chemical warfare agent simulant dipropyl sulfide (DPS), with the highest adsorption capacity being 202.38 mg/g. The effects of the initial concentration of DPS and temperature on the adsorption performance of ACF felt were investigated. Meanwhile, a plausible adsorption mechanism was proposed based on the kinetic analysis and fitting of different adsorption isotherm models. The results demonstrated that the adsorption process of DPS onto ACF felt could be well fitted with a pseudo-second-order equation, indicating a synergistic effect of chemical adsorption and physical adsorption. We anticipate that this work could be helpful to the design and development of advanced ACF felts for the application of breathable chemical protection clothing. Full article

Granular activated carbon (GAC) has proven to be an effective adsorbent for removing the chemical warfare agent sarin (GB) and simulants like Dimethyl methylphosphonate (DMMP). However, it comes with certain limitations, including inadequate contact efficiency, notable mass transfer resistance, and lower bed utilization efficiency. This study synthesized steel fiber-entrapped activated carbon composites (SFEACs), which exhibited a maximum adsorption capacity of 285.3 mg/g at 303 K. Compared with the packed bed (PB) filled with GAC, while the adsorption capacity of SFEACS decreased, there was a substantial increase in the adsorption mass transfer rate. These SFEACs were combined with GAC to create a structural fixed bed (SFB), which demonstrated excellent performance in DMMP removal. Under identical experimental conditions, the DMMP breakthrough curve of SFB exhibited a steeper profile compared to the packed bed (PB) filled with GAC at the same bed height, and the breakthrough time against DMMP vapor could be extended by 13.8%. Furthermore, the adsorption rate constant of the Yoon-Nelson model increased by more than 17.6%, and the unused bed length, according to the Wheeler–Jonas model, decreased by more than 14%. Full article

It is both important and required to quickly and accurately detect chemical warfare agents, such as the highly toxic nerve agent sarin. Surface-enhanced Raman scattering (SERS) has received considerable attention due to its rapid results, high sensitivity, non-destructive data acquisition, and unique spectroscopic fingerprint. In this work, we successfully prepared SERS cotton swabs (CSs) for the detection of the sarin simulant agent dimethyl methyl phosphonate (DMMP) by anchoring N1-(3-trimethoxysilylpropyl) diethylenetriamine (ATS)/silver nanoparticle (AgNP) nanocomposites on CSs using ATS as the stabilizer and coupling agent. Simultaneously, the binding mode and reaction mechanics between the AgNP, ATS, and CS were confirmed by XPS. The modified CSs exhibited good uniformity, stability, and adsorption capability for SERS measurements, enabling the adsorption and detection of DMMP residue from an irregular surface via a simple swabbing process, with a detection limit of 1 g/L. The relative standard deviations (RSDs) of RSD₇₁₀ = 5.6% had high reproducibility. In this research, the fabrication method could easily be extended to other cellulose compounds, such as natural fibers and paper. Furthermore, the versatile SERS CSs can be used for the on-site detection of DMMP, particularly in civil and defense applications, to guarantee food security and the health of the population. Full article

Chemical warfare agents (CWAs) have been threatening human civilization and its existence because of their rapid response, toxic, and irreversible nature. The hybrid nanostructured composites were synthesized by the hydrothermal process to detect the dimethyl methyl phosphonate (DMMP), a simulant of G-series nerve agents, especially sarin. Cellulose (CE), manganese oxide cellulose (MnO₂@CE), and MnO₂@CE/polypyrrole (PPy) exhibited a frequency shift of 0.4, 4.8, and 8.9 Hz, respectively, for a DMMP concentration of 25 ppm in the quartz crystal microbalance (QCM). In surface acoustic wave (SAW) sensor, they exhibited 187 Hz, 276 Hz, and 78 Hz, respectively. A comparison between CE, MnO₂@CE, and MnO₂@CE/PPy demonstrated that MnO₂@CE/PPy possesses excellent linearity with a coefficient of determination (COD or R²) of 0.992 and 0.9547 in the QCM and SAW sensor. The hybrid composite materials showed a reversible adsorption and desorption phenomenon in the reproducibility test. The response and recovery times indicated that MnO₂@CE/PPy showed the shortest response (~23 s) and recovery times (~42 s) in the case of the QCM sensor. Hence, the pristine CE and its nanostructured composites were compared to analyze the sensing performance based on sensitivity, selectivity, linearity, reproducibility, and response and recovery times to detect the simulant of nerve agents. Full article

Chemical warfare agents (CWAs) are highly toxic and fast-acting and are easy to cause large-scale poisoning to humans and livestock after being released. The activated carbon used for CWAs adsorption has disadvantages of limited adsorption capacity, easy aging and deactivation. Metal oxides have environmental stability, and they are characterized by long lasting and broad spectrum when used for thermal catalytic decomposition. Therefore, in this study, the supported copper–cerium catalyst CuO-CeO₂/γ-Al₂O₃ was prepared using an equal volume impregnation method. The thermal catalytic decomposition performance was studied using sarin CWAs simulant dimethyl methyl phosphonate (DMMP) as the target compound. The results show that the CuO-CeO₂/γ-Al₂O₃ catalyst with a CeO₂ loading of 5% exhibited better thermal catalytic decomposition performance of DMMP. The catalyst provided protection against DMMP for 237 min at 350 °C; CuO was highly dispersed on CuO-5% CeO₂/γ-Al₂O₃, and there was a strong interaction between Cu and Ce on CuO-5% CeO₂/γ-Al₂O₃, which promoted the generation of surface-adsorbed oxygen, leading to a better thermal catalytic decomposition performance of DMMP. This study is expected to provide a reference for the study of catalysts for the thermal catalytic decomposition of CWAs. Full article

Humidity in the air can significantly limit the adsorption capacity of porous materials used for the removal of chemical warfare agents (CWAs). Therefore, in this work, we prepared a porous organic material (C-1) and its fluoride derivative (C-1-F) via a Schiff base reaction and determined their structure and morphological properties, hydrophobicity, and adsorption capacity. Compared to the parent C-1 material, both the channel and particle surface of C-1-F were highly hydrophobic, thus stabilizing the fluorinated porous material under various humidity conditions. Dimethyl methyl phosphonate was used as a nerve agent simulant to examine the efficiency of the synthesized porous materials, indicating that C-1-F had a higher adsorption capacity than C-1 under dry conditions. Moreover, unlike C-1, the adsorption capacity of hydrophobic C-1-F was not affected even under a relative humidity of 20%, and it is still able to maintain high adsorption capacity at a relative humidity of 60%, suggesting its high application potential in the removal of CWAs. Full article

Dimethyl methylphosphonate (DMMP) is an important simulant of organophosphates pesticides and chemical warfare nerve agents. Here, we investigated the catalytic decontamination of DMMP on Fe-oxide impregnated mesoporous Al₂O₃. Fe-oxide/Al₂O₃ sample was prepared via the temperature regulated chemical vapor deposition of Fe-oxide on mesoporous Al₂O₃ and post-annealing at 750 °C. The Fe-oxide/Al₂O₃ and bare Al₂O₃ samples were exposed to DMMP-containing dry air at room temperature to study the effects of Fe-oxide impregnation on the reactive adsorption of DMMP. The facilitation of DMMP degradation into CO₂ and methanol at room temperature in the presence of nano-dispersed Fe-oxide was evidenced by gas-chromatograph and Fourier transform-infrared (FT-IR) absorption spectroscopy. In addition, temperature programmed oxidation (TPO) experiments and gas chromatography (Agilent, 6890) equipped with mass spectrometer (Agilent, 5973N) (GC/MS) analyses revealed that the minimum temperature that was required for total oxidation of DMMP into CO₂ can also be lowered by Fe-oxide impregnation in mesoporous Al₂O₃. Full article

Sensitive, selective and fast detection of chemical warfare agents is necessary for anti-terrorism purposes. In our search for functional materials sensitive to dimethyl methylphosphonate (DMMP), a simulant of sarin and other toxic organophosphorus compounds, we found that zinc oxide (ZnO) modification potentially enhances the absorption of DMMP on a manganese dioxide (MnO₂) surface. The adsorption behavior of DMMP was evaluated through the detection of tiny organophosphonate compounds with quartz crystal microbalance (QCM) sensors coated with ZnO-modified MnO₂ nanofibers and pure MnO₂ nanofibers. Experimental results indicated that the QCM sensor coated with ZnO-modified nanostructured MnO₂ film exhibited much higher sensitivity and better selectivity in comparison with the one coated with pure MnO₂ nanofiber film. Therefore, the DMMP sensor developed with this composite nanostructured material should possess excellent selectivity and reasonable sensitivity towards the tiny gaseous DMMP species. Full article