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.

Early prediction and prevention of infected pancreatic necrosis

Approximately 20%-30%of patients with acute necrotizing pancreatitis develop infected pancreatic necrosis(IPN),a highly morbid and potentially lethal complication.Early identification of patients at high risk of IPN may facilitate appropriate preventive measures to improve clinical outcomes.In the past two decades,several markers and predictive tools have been proposed and evaluated for this purpose.Conventional biomarkers like C-reactive protein,procalcitonin,lymphocyte count,interleukin-6,and interleukin-8,and newly developed biomarkers like angiopoietin-2 all showed significant association with IPN.On the other hand,scoring systems like the Acute Physiology and Chronic Health Evaluation II and Pancreatitis Activity Scoring System have also been tested,and the results showed that they may provide better accuracy.For early prevention of IPN,several new therapies were tested,including early enteral nutrition,anti-biotics,probiotics,immune enhancement,etc.,but the results varied.Taken together,several evidence-supported predictive markers and scoring systems are readily available for predicting IPN.However,effective treatments to reduce the incidence of IPN are still lacking apart from early enteral nutrition.In this editorial,we summarize evidence concerning early prediction and prevention of IPN,providing insights into future practice and study design.A more homo-geneous patient population with reliable risk-stratification tools may help find effective treatments to reduce the risk of IPN,thereby achieving individualized treatment.

Theoretical simulation study of laser-induced plasma bombardment on bacteria

With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards,it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-induced plasma.This study employs a two-dimensional axisymmetric fluid dynamics model to simulate the power density of plasma bombardment on bacteria and access its decontamination effects.The model considers the transport processes of vapor plasma and background gas molecules.Based on the destructive impact of high-speed moving particles in the plasma on bacteria,we investigate the bombardment power density under various conditions,including different laser spot sizes,wavelengths,plate's tilt angles,and plate-target spacing.The results reveal that the bombardment power density increases with a decrease in laser spot size and wavelength.For instance,when the plate is parallel to the target surface with a 1 mm spacing,the bombardment power density triples as the laser spot size decreases from 0.8 mm to 0.5 mm and quadruples as the wavelength decreases from 1064 nm to 266 nm.Notably,when the plate is parallel to the target with a relatively close spacing of 0.5 mm,the bombardment power density at 0°inclination increases sevenfold compared to 45°.This simulation study is essential for optimizing optical parameters and designing component layouts in decontamination devices using laser-induced plasma.The reduction of laser spot size,wavelength,plate-target spacing and aligning the plate parallel to the target,collectively contribute to achieving precise and effective decontamination.

Hybrid electric discharge plasma technologies for water decontamination:a short review

Electric discharge plasma(EDP)can efficiently degrade aqueous pollutants by its in situ gen erated strong oxidative species(OH,0,H2O2.O.etc)“nd other physiochemical effects(UV irradiation,shockwaves,local high temperature,etc),but a high energy consumptions limit the application of EDP in water treatment.Some adsorbents,catalysts,and oxida nts have been employed for en hanci ng the degradation of pollutants by discharge plasma.These hybrid plasma technologies offer improved water treatment performance compared to dischai'ge plasma alone.This paper reviews the water decontamination performance and mechanisms of these hybrid plasma technologies,and some suggestions on future water treatment technologies based on discharge plasma are also proposed.

Selective intestinal decontamination for the prevention of early bacterial infections after liver transplantation

Bacterial infection in the first month after liver transplantation is a frequent complication that poses a serious risk for liver transplant recipients as contributes substantially to increased length of hospitalization and hospital costs being a leading cause of death in this period. Most of these infections are caused by gramnegative bacilli, although gram-positive infections, especially Enterococcus sp. constitute an emerging infectious problem. This high rate of early postoperative infections after liver transplant has generated interest in exploring various prophylactic approaches to surmount this problem. One of these approaches is selective intestinal decontamination(SID). SID is a prophylactic strategy that consists of the administration of antimicrobials with limited anaerobicidal activity in order to reduce the burden of aerobic gram-negative bacteria and/or yeast in the intestinal tract and so prevent infections caused by these organisms. The majority of studies carried out to date have found SID to be effective in the reduction of gram-negative infection, but the effect on overall infection is limited due to a higher number of infection episodes by pathogenic enterococci and coagulase-negative staphylococci. However, difficulties in general extrapolation of the favorable results obtained in specific studies together with the potential risk of selection of multirresistant microorganisms has conditioned controversy about the routinely application of these strategies in liver transplant recipients.

Surface Decontamination of Chemical Agent Surrogates Using an Atmospheric Pressure Air Flow Plasma Jet

An atmospheric pressure dielectric barrier discharge （DBD） plasma jet generator using air flow as the feedstock gas was applied to decontaminate the chemical agent surrogates on the surface of aluminum, stainless steel or iron plate painted with alkyd or PVC. The experi- mental results of material decontamination show that the residual chemical agent on the material is lower than the permissible value of the National Military Standard of China. In order to test the corrosion effect of the plasma jet on different material surfaces in the decontamination pro-cess, corrosion tests for the materials of polymethyl methacrylate, neoprene, polyvinyl chloride （PVC）, polyethylene （PE）, phenolic resin, iron plate painted with alkyd, stainless steel, aluminum, etc. were carried out, and relevant parameters were examined, including etiolation index, chroma- tism, loss of gloss, corrosion form, etc. The results show that the plasma jet is slightly corrosive for part of the materials, but their performances are not affected. A portable calculator, computer display, mainboard, circuit board of radiogram, and a hygrometer could work normally after being treated by the plasma jet.

Results of gastroscope bacterial decontamination by enzymatic detergent compared to chlorhexidine

AIM： To compare the efficacy of enzymatic detergent with chlorhexidine for gastroscope bacterial decontamination. METHODS： A prospective randomized controlled study was undertaken to evaluate the ability of these 2 agents to achieve high level disinfection in a gastroscope. A total of 260 samples were collected from 5 different gastroscopes. Manual cleaning was done for 10 min with these 2 agents separately （n = 130 each）. Then all specimens underwent 2% glutaraldehyde soaking for 20 min. After 70% alcohol was rinsed, sterile normal saline was flushed into each gastroscope channel and 40 mL of sample was collected. The sample was sent for aerobic bacterial culture after membrane was filtered. A colony count greater than 200 cfu/mL was considered significant. RESULTS： The positive culture rate was 4.6% in the enzymatic detergent arm and 3.1% in the chlorhexidine arm. Pseudomonas species were the main organism detected from both groups （60%）. Multiple organisms were found from 4 specimens （enzymatic detergent arm = 1, chlorhexidine arm = 3）. CONCLUSION： The contamination rate of both types of cleaning solution is equivalent.

Decontamination of 2-Chloroethyl Ethyl Sulfide by Pulsed Corona Plasma

Decontamination of 2-chloroethyl ethyl sulfide （2-CEES, CH_3CH_2SCH_2CH_2C1） by pulsed corona plasma was investigated. The results show that 212.6 mg/m^3 of 2-CEES, with the gas flow rate of 2 m^3/h, can be decontaminated to 0.09 mg/m^3. According to the variation of the inlet and outlet concentration of 2-CEES vapor with retention time, it is found that the reaction of 2-CEES in a pulsed corona plasma system follows the first order reaction, with the reaction rate constant of 0.463 s^-1. The decontamination mechanism is discussed based on an analysis of the dissociation energy of chemical bonds and decontamination products. The C-S bond adjacent to the C1 atom will be destroyed firstly to form CH3CH2S. and .CH2CH2C1 radicals. CH3CH2S. can be decomposed to .C_2H_5 and .S..S can be oxidized to SO_2, while .C_2H_5 can be finally oxidized to CO_2 and H_2O. The C-Cl bond in the .CH_2CH_2C1 radical can be destroyed to form .CH_2CH_2. and .C1, which can be mineralized to CO_2, H_2O and HCl. The H atom in the .CH_2CH_2C1 radical can also be substituted by -C1 to form CHCl_2-CHCl_2.

Utilization of Various Analogy of Synthetic Nanoporous Zeolites and Composite of Zeolites for Decontamination/Detoxification of CWA Simulants—An Updated Review

In this review, we summaries the past few year work on the chemistry of CWA’s and their simulants on various heterogeneous surfaces of zeolites, composites of zeolites and doped zeolite with transition metal oxides. This review elaborates an updated literature overview on the degradation of CWA’s and its simulants. The data written in this review were collected from the peer-reviewed national and international literature.

Modified wool-iron biopolymer-based complex as an active heterogeneous decontamination photocatalyst

A series of biopolymer based complex were manufactured by coordinating iron ions to the abundant amino-and sulfur-containing groups in the modified wool and used as heterogeneous Fenton-like photocatalyst for 4-chlorophenol (4-CP) degradation in the presence of H2O2. Hydroxylamine hydrochloride (NH2OH center dot HCl) or acrylic acid was employed to modify the natural wool to strengthen the interaction with iron and to reinforce the structural stability. The NH2OH center dot HCl modified wool based complex showed the best catalytic performance for 4-CP degradation. The strong coordination between iron and great number of hydroxamic acid in this modified complex leads to the least iron leaching during the tests. HO center dot species was confirmed to be the dominant reactive oxidant in the decontamination process. The approach presented in this study can provide a new approach for developing novel bioployermer-based photocatalysts for efficient degradation of toxic organic pollutants such as 4-CP. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Plasma activated water prepared by different plasma sources:physicochemical properties and decontamination effect on lentils sprouts

The pulsed corona discharge(CD)generated in contact with water and directly in water,and high-power air plasma jet(APJ)were studied for production of plasma activated water(PAW).The changes of physical(pH,redox potential,conductivity,temperature)and chemical(peroxides,nitrites,nitrates concentrations)properties of treated water were investigated.The comparison of CD generated in gas/water interface and underwater configuration in the same system showed that the interaction of reactive oxygen and nitrogen species formed in ambient air in gas/water system induces different chemical processes,leading to lower pH,higher oxidation-reduction potential(ORP)and higher conductivity of PAW than in underwater discharge.High yield of peroxide was observed in both configurations.The PAW prepared by APJ exhibits high concentration of nitrites and nitrates according to supplied energy,and related significant decrease of pH and increase of ORP and conductivity after treatment.The antimicrobial effect of PAW prepared by CD and plasma jet on lentils sprouts was studied in different treatment and washing times.The APJ appears to have great efficacy on water activation resulted in strong decontamination effect.The PAW treated by APJ for 10 min led to bacterial reduction from initial 8.3 to 5.9 and 4.0 log10 CFU g^(-1)after 10 and 30 min of washing,respectively.

A Novel Visible-light-responsive Photocatalyst Bi1.5Cr0.5WO6 with Suitable Bandgap Structure and Its Application in Water Decontamination

Integrating the advantages of Bi and Cr elements in the bandgap engineering of metal oxides, a visible-light-responsive photocatalyst Bi1.5Cr0.5WO6 is successfully constructed and initially applied in water decontamination. The combination of UV-vis diffuses reflectance and the Mott-Schottky curve from electrochemical testing can be used to determine the conduction band and valence band of Bi1.5Cr0.5WO6 to be about –1.26 and 1.42 V, respectively. The location of energy band structure indicates that the superoxide free radical can be produced in Bi1.5Cr0.5WO6 photocatalytic system without hydroxyl group. This speculation is also confirmed by ESR experiment and active radical species scavenging experiments. In addition, the best photocatalytic performance of Bi1.5Cr0.5WO6 obtained under 180 ℃ is attributed to the smallest impedance and the strongest electronic migration capability.

Estimation of exposure dose for decontamination workers from contaminated soil at a nuclear decommissioning site in Korea

Assessment of the exposure dose for workers is crucial to protecting workers from the radiological risk.This preliminary study estimates the potential radiological exposure for a soil remediation worker at a nuclear decommissioning site contaminated with Cs-137 in Korea,and then calculates the maximum workable soil concentration to comply with the occupational dose constraint of 20 mSv per year.The Korean characteristic data,detailed exposure scenarios for workers by the type of work,and relevant exposure pathways were used in the dose estimation.As a result,the most severe exposure-induced work type was identified as the excavator operation with an annual individual dose of 5.92×10^-5 mSv for a unit concentration of soil,from which the derived maximum workable soil concentration was 3.38×105 Bq/kg.Furthermore,dose contribution by each exposure pathway was found to be decreased in the following order:external radiation exposure,soil ingestion,dust inhalation,and skin contamination.The results of this study are expected to be used effectively to optimize radiation protection for workers and establish appropriate work procedures for future site remediation.

Decommissioning of Uranium Pilot Plants at IPEN-CNEN/SP： Facilities Dismantling, Decontamination and Reuse as New Laboratories for Strategic Programs

From beginning of 90＇s, the Brazilian nuclear policy has been changed radically. This determined the interruption of most R＆D fuel cycle activities and the facilities shutdown at Nuclear and Energetic Research Institute （IPEN）. The existence of those facilities also implicated in the need of constant surveillance, representing additional obligations, costs and problems. The reasons to promote the dismantling of the IPEN＇s Nuclear Fuel Cycle Pilot Plants elapsed mainly from the need of physical space for new activities, since the R＆D in the nuclear fuel cycle area were interrupted. In the last decade, IPEN has changed its ＂nuclear profile＂ to a ＂comprehensive and multidisciplinary profile＂. With the end of most nuclear fuel cycle activities, the former facilities were distributed in four different centers. Each center has adopted a different strategy and priority to face the D＆D problem. The available resources depend on the specific program in each area＇s development （resources available from other sources, not only from Brazilian National Nuclear Energy Commission （CNEN）. One of those new activities is the IPEN＇s Environmental Program. This paper describes the procedures, problems faced and results related to the reintegration of the former pilot plant areas as new laboratories of the Chemical and Environmental Technology Center-CQMA of the IPEN.

Smart decontamination device for small-size radioactive scrap metal:using abrasion pin in rotating magnetic field and ultrasonic wave cleaner

A smart decontamination device is developed for small-size radioactive scrap metal(SSRSM)arisen from nuclear facilities.The abrasion pin in rotating magnetic field and ultrasonic wave cleaner are used for solving the problems of the second decontamination and high treatment cost.At first,the decontamination efficiency of each device is improved by upgrading the design.Optimal operating conditions are determined for each device.Next,both techniques are applied sequentially.Experimental results show that the efficiency of combined decontamination device is higher than that of each device.With the use of the developed device,the various SSRSMs are decontaminated for 15 min treatment in magnetic abrasion device and15 min treatment in ultrasonic cleaning device.Decontamination index ranges from18 to 56.Absolute values of all decontaminated samples are below the background value.

Wastewater Decontamination from Microorganisms by Electrospraying Corona Discharge

A novel water treatment technique, based on a combination of electrospraying and pulsed corona discharge, has been used for bio-decontamination of wastewater. The electrospraying process has been found to increase the surface area of the treated wastewater, and hence increases the efficiency of the corona treatment process. The phase diagram of the discharge, which characterizes the discharge regimes, has been identified experimentally. The survival ratio of the microorganisms has been investigated experimentally as a function of the applied voltage and the numbers of treatment runs using air and oxygen as working gases. Microorganism surface has been examined using scanning electron microscope (SEM), which enabled in understanding the decontamination mechanisms of the treated microorganism. A complete decontamination has been achieved after only one run for an applied voltage higher than 16 kV when the discharge system was operated in oxygen gas. Optical emission spectrum of the electrosprayed water confirmed the existence of OH-radicals responsible for decontamination process.

Optical Decontamination of Large Areas Containing Airborne Microorganisms at Different Phases of Growth

Background:Microorganisms transferred by water,air,and human such as bacteria and viruses can reach inanimate surfaces with high rates of contamination.In general,the objectives of the research were to evaluate the decontamination of large areas such as floors,using a mobile device with ultraviolet C light at different delivery times and also to evaluate these microbial loads in stationary or latent phases.Material and methods:The microbial inactivation effects of this device were measured through the recovery of viable bacteria in different points of the applied area.Results:A significant microbial reduction(p≤0.05)of 60-87%was obtained in general for all groups and for groups with stationary phase reductions of 100%.Conclusions:microbial inactivation with UV-C ultraviolet light administration rates presents the possibility of potential use on surfaces of large areas for the decontamination of microorganisms in latent and stationary phases.

Molten Salts as Stripping Media for Radioactive Superficial Decontamination

The main practical difficulty associated to the task of the dismantling and decommissioning of the IPEN＇s old nuclear fuel cycle facilities has been the big amount of radioactive waste generated in the dismantling operations. The waste is mainly in the form of contaminated carbon steel structures. In the IPEN, the presence of contamination in the equipments, structures and buildings, although restricted to low and medium activity levels, constituted an important concern due, on one hand, to the great volume of radioactive wastes generated during the operations. On the other hand, it should be outstanding that the capacity of radioactive wastes stockpiling in IPEN found been exhausted. In function of the large waste volume generated in the dismantling operations, the main concems and focuses of research and technological development in the IPEN＇s Chemical and Environmental Center--CQMA have been the effluent and waste treatment subjects, besides the development of some special decontamination techniques, since most old nuclear fuel cycle facilities are installed in the CQMA＇s area. The reduction of the radioactive waste volume has a significant impact in the decommissioning costs and in the amount of material to be stored. The mentioned steel structures, during the operations and after ten or twelve years after the facilities shut down, have presented severe corrosion. In the past, to protect them, several layers of paint were applied. Traditional decontamination methods were tried, such as acid pickling, alkaline washing and ultrasonic baths. Nevertheless, these methods have failed to reach effective decontamination. In this paper, we described some aspects and problems in decommissioning of IPEN＇s nuclear fuel cycle facilities and it is presented an innovative method for radioactive superficial decontamination of steel structures using different molten salt compositions and temperatures as stripping media.

The Optimization of Decontamination Methods Selected for Contaminated Areas Used in Decommissioning of CANDU-6 NPP

The objective of this paper is to provide information for nuclear field specialists and decision makers on opportunities for minimizing radioactive wastes arising from the decontamination ＆ decommissioning of a CANDU-6 NPP. The paper proposes a method for selection of appropriate decontamination techniques which may be used at Cernavoda NPP decommissioning, equipped with CANDU heavy water reactors, based on the simulation with ProVision software. The paper has a singular focus on physical decontamination techniques and does not address other aspects of decommissioning. The physical decontamination techniques which are the best for certain areas of the CANDU-6 NPP from point of view of effectiveness and cost were determined. A unit cost for each decontamination technique was determined by relating the total cost to the average surface to be decontaminated. In conclusion, physical techniques will apply more efficiently to concrete surfaces. The chemical decontamination methods, in comparison with physical decontamination methods are. more suitable for non-porous surfaces respectively metal and are less recommended for concrete surfaces.

Review of advanced oxidation processes for treating hospital sewage to achieve decontamination and disinfection

Hospital sewage contains various harmful pharmaceutical contaminants(e.g.,antibiotics,anti-inflammatory agents,and painkillers)and pathogens(e.g.,bacteria,viruses,and parasites),whose direct discharge into the environment will induce diseases and pose a powerful threat to human health and safety,and environmental ecology.In recent years,advanced oxidation processes(AOPs),particularly photocatalysis,electrocatalysis,and ozone catalysis have been developed as widespread and effective techniques for hospital sewage treatments.However,there is a lack of systematic comparison and review of the prior studies on hospital sewage treatment using AOPs systems.This review elaborates on the mechanisms,removal efficiencies,and advantages/disadvantages of these AOPs systems for hospital wastewater decontamination and disinfection.Meanwhile,some novel and potential technologies such as photo-electrocatalysis,electro-peroxone,Fenton/Fenton-like,and piezoelectric catalysis are also included and summarized.Moreover,we further summarize and compare the capacity of these AOPs to treat the actual hospital wastewater under the impact of the water matrix and pH,and estimate the economic cost of these technologies for practical application.Finally,the future development directions of AOPs for hospital wastewater decontamination and disinfection have been prospected.Overall,this study provides a comparison and overview of these AOP systems in an attempt to raise extensive concerns about hospital wastewater decontamination and disinfection technologies and guide researchers to discover the future directions of technologies optimization,which would be a crucial step forward in the field of hospital sewage treatment.