Multiple chemical warfare agent simulant decontamination by self-driven microplasma

Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future.

A prototype portable instrument employing micro-preconcentrator and FBAR sensor for the detection of chemical warfare agents

The presence of chemical warfare agents(CWAs)in the environment is a serious threat to human safety,but there are many problems with the currently available detection methods for CWAs.For example,gas chromatography–mass spectrometry cannot be used for in-field detection owing to the rather large size of the equipment required,while commercial sensors have the disadvantages of low sensitivity and poor selectivity.Here,we develop a portable gas sensing instrument for CWA detection that consists of a MEMSfabricated micro-preconcentrator(μPC)and a film bulk acoustic resonator(FBAR)gas sensor.The μPC is coated with a nanoporous metal–organic framework material to enrich the target,while the FBAR provides rapid detection without the need for extra carrier gas.Dimethyl methylphosphonate(DMMP),a simulant of the chemical warfare agent sarin,is used to test the performance of the instrument.Experimental results show that the μPC provides effective sample pretreatment,while the FBAR gas sensor has good sensitivity to DMMP vapor.The combination of μPC and FBAR in one instrument gives full play to their respective advantages,reducing the limit of detection of the analyte.Moreover,both the μPC and the FBAR are fabricated using a CMOS-compatible approach,and the prototype instrument is compact in size with high portability and thus has potential for application to in-field detection of CWAs.

Wearable membranes from zirconium-oxo clusters cross-linked polymer networks for ultrafast chemical warfare agents decontamination

The urgent need for immediate personal protection against chemical warfare agents(CWAs)spurs the requirement on robust and highly efficient catalytic systems that can be conveniently integrated to wearable devices.Herein,as a new concept for CWA decontamination catalyst design,sub-nanoscale,catalytically active zirconium-oxo molecular clusters are covalently integrated in flexible polymer network as crosslinkers for the full exposure of catalytic sites as well as robust framework structures.The obtained membrane catalysts exhibit high swelling ratio with aqueous content as 84 wt%and therefore,demonstrate quasi-homogeneous catalytic activity toward the rapid hydrolysis of both CWA,soman(GD)(t_(1/2)=5.0 min)and CWA simulant,methyl paraoxon(DMNP)(t_(1/2)=8.9 min).Meanwhile,due to the covalent nature of cross-linkages and the high flexibility of polymer strands,the membranes possess promising mechanical strength and toughness that can stand the impact of high gas pressures and show high permeation for both CO_(2)and O_(2),enabling their extended applications in the field of collective/personal protective materials with body comfort.

Protection of armoured vehicles against chemical, biological and radiological contamination

The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical,biological and radiological contamination.This applies to vehicles with additional passive,reactive and hybrid protection in the form of cassettes against piercing with anti-tank projectiles,piercing with their kinetic energy of impact,and as a result of chemical energy of shaped charges as well as explosively formed projectiles.It has been shown how increased ballistic protection of these vehicles at the same time reduces their decontaminability in various places of the vehicle due to the increased additional surface of the vehicle with cassettes.Prevention of contamination of these cassettes has been presented as a way of reducing hard to reach surface for decontamination and a method of insulating construction elements(stands),fixing these cassettes to the vehicle,from the environment to prevent contact with contaminated liquids and dusts.The selection of appropriate materials is shown,which may affect the improvement of the decontamination efficiency of the vehicle with such cassettes.This applies to the use of materials with low absorption of chemical warfare agents,which prevent the accumulation of large amounts of these agents on contaminated surfaces and improve the effectiveness of decontamination.It also shows how to ensure better access of the disinfectant to as much of the vehicle surface as possible,covered with cassettes that have been contaminated.It shows how a vehicle,in particular with such cassettes,can provide protection against radar detection when Radar Absorbent Material is used on vehicle cassettes.

Portable System for CWA Detection Using Micro Array Gas Sensor

Biochemistry weapon is raising new tools of war and terror.This research is an experiment about portable system for CWAs (chemical warfare agents) detection using micro array gas system.CWAs were divided into four types such as blood, nerve,vesicant,and choking agent.To detect various CWAs,semiconductor thick film sensor array based on tin oxide was fabricated and their gas responses were examined.Operating temperature was range of 250℃to 350℃and gas concentration was range of 0.1μg/g to 10μg/g.Sensor array was measured as operating temperatures,concentrations for four simulant agents of CWAs.Extracted parameters from results were carried out classification among CWAs through the principal component analysis (PCA).Also,classification of gases is studied using adaptive resonance theory (ART) that is one of neural network algorithm.Results displayed using PDA system.

Synthesis and Gas Sensing of TiO_2 Ultrafine Powders by Precipitating

We investigated the gas sensing characteristics of rutile and anatase TiO_2 nano-particle sensors for chemical warfare agents.TiO_2 nano-powders with rutile and anatase structure were fabricated by controlling pH value without heat treatment respectively.The mean particle size of TiO_2 powders were below 10 nm.As-prepared TiO_2 powders have several advantages of nano particle size and high surface area and could be a prominent candidate for nano-sensors.TiO_2 sensors were examined with DMMP for chemical warfare agents detection.

Cerium dioxide as a new reactive sorbent for fast degradation of parathion methyl and some other organophosphates

Cerium dioxide was used for the first time as reactive sorbent for the degradation of the organophosphate pesticides para-thion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-（diisopropylamino） ethyl] methylphosphonothioate （VX）. CeO2 specimens were prepared by calcination of basic cerous carbonate obtained by precipitation from an aqueous solution. The CeO2 samples containing certain amounts （1 wt.%-5 wt.%） of the neighboring lanthanides （La, Pr, Nd） were prepared in a similar way from pure lanthanide salts. It was shown that ceria accelerated markedly the decomposition of parathion methyl causing the cleavage of the P-O-aryl bond in the pesticide molecule. A similar reaction mechanism was proposed for the degradation of other organophosphate pesticides and nerve agents. The degradation times （reaction half-times） were in an order of minutes in the presence of CeO2, compared to hours or days under common environ-mental conditions. The reaction in suitable organic solvents allowed conversions of about 90%for parathion methyl loading of 20 mg pesticide/g CeO2 within 2 h with a reactant half-life in the order of 0.1 min. The key parameter governing the degradation efficiency of CeO2 was the temperature during calcination. At optimum calcination temperature （about 773.15 K）, the produced ceria retained a sufficiently high surface area, and attained an optimum degree of crystallinity （related to a number of crystal defects, and thus poten-tial reactive sites）. The presence of other lanthanides somewhat decreased the reaction rate, but this effect was not detrimental and permitted the possible use of chemically impure ceria as a reactive sorbent. A fast organophosphate degradation was demonstrated not only in non-polar solvents （such as heptane）, but also in polar aprotic solvents （acetonitrile, acetone） that are miscible with water. This opens new possibilities for designing more versatile decontamination strategies. The cleavage of phosphate ester bonds is of a great importance not only for the degradation of dangerous chemicals （chemical weapons, pesticides）, but also for interactions of ceria （es-pecially the nano-sized one） in biologically relevant systems.

Recent advances in polyoxoniobate-catalyzed reactions

The search for polyoxometalate-based catalysts has long attracted interest.Being designable in structure,stable and effective,polyoxoniobate-based catalysts have an exciting prospect for industrial applications.This paper not only summarizes recent advances in classic polyoxoniobate-catalyzed reactions,including chemical warfare agents and organic dyes degradation,epoxidation reactions,photocatalytic hydrogen evolution and base-catalyzed reactions but also discusses some representative cases and the speculative mechanism related to structures.In addition,the current challenges and perspectives in the fabrication of more efficient and promising polyoxoniobate-based catalysts are also presented.

Influence of morphology on basicity of CeO2 and its use in 2-chloroethyl ethyl sulfide degradation

Three CeO_2 samples with different morphologies, i.e., cubes, rods, and spindles, were synthesized and investigated for 2-chloroethyl ethyl sulfide（2-CEES） degradation. The samples were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, the Brunauer-Emmett-Teller method, and temperature-programmed CO_2 desorption. It was found that morphologies of CeO_2 could strongly affect the surface properties and the 2-CEES degradation activities. The surface basicity and the continuous 2-CEES degradation activity of spindle-like CeO_2 were much better than those of the other CeO_2 samples, although all the samples had identical chemical compositions. That was benefited by the largest surface area, abundant microcracks, and surface oxygen vacancies of the spindle-like CeO_2.

Preparation of a porphyrin-polyoxometalate hybrid and its photocatalytic degradation performance for mustard gas simulant 2-chloroethyl ethyl sulfide

By combining 5,10,15,20-tetra(4-chlorine)phenylporphyrin(TClPP)andα-Keggin polyoxometalate H_(5)PV_(2)Mo_(10)O_(40)(H 5 PVMo)via a simple ion-exchange method,an organic-inorganic hybrid material[C_(44)H_(28)N_(4)Cl_(4)]_(1.5)[H_(2)PMo_(10)V_(2)O_(40)]·2C_(2)H_(6)O(H_(2 )TClPP-H_(2) PVMo)was prepared and thoroughly characterized by a variety of techniques.The homogeneous photocatalytic degradation of 2-chloroethyl ethyl sulfide(CEES)(5μL)by H_(2) TClPP-H_(2) PVMo(1×10^(−6)mol/L)was studied in methanol and methanol-water mixed solvent(v/v=1:1),in which the degradation rate of CEES reached 99.52%and 99.14%,respectively.The reaction followed first-order reaction kinetics,and the half-life and kinetic constant in methanol and the mixed solvent were respectively 33.0min,−0.021 min−1 and 15.7min,−0.043 min−1.Mechanism analysis indicated that under visible light irradiation in the air,CEES was degraded via oxidation and alcoholysis/hydrolysis in methanol and the mixed solvent.O_(2)·−and ^(1)O_(2) generated by H_(2) TClPP-H_(2) PVMo selectively oxidized CEES into a nontoxic sulfoxide.Singlet oxygen capture experiments showed that H_(2) TClPP-H_(2) PVMo(φ=0.73)had a higher quantum yield of singlet oxygen than TClPP(φ=0.35)under an air atmosphere and visible light irradiation.

Hyphenated Techniques in Liquid Chromatography and their Applications in Forensic Toxicology:A Review

Conventional analytical methods,such as gas chromatography,high performance liquid chromatography(LC),ultra-violet,and others,are ineffective in addressing the increasing number of problems in forensic toxicology.Hyphenated analytical methods,wherein the separation method are coupled or combined with spectral methods,with the help of a proper interface,are the available alternative options.The key benefits of these methods are the requisites of low limits for detection,shorter analytical time,the possibility of automation,better reproducibility,and high precision and repeatability.This review discusses on some of the hyphenated analytical methods that involve LC as the separation tool,for their most recent applications in the area of forensic toxicology focusing on the screening of drugs of abuse,the usage of alternative matrices for monitoring drug abuse,analysis of chemical warfare agents,determination of doping agents and related substances,natural toxins,environmental poisons,and examination of food produce adulteration.The incorporation of the more user-friendly LC-interfaces,such as atmospheric pressure chemical ionization,and electrospray ionization in the LC-mass spectrometry has increased the popularity of this technique tremendously among scientists of different disciplines.Hyphenated approaches have extremely low constraints regarding the identification and quantification,and offer high reproducibility,with unparalleled potential.