Decontamination Agents Research Articles

Field and laboratory perspectives on fentanyl and carfentanil decontamination

Abuse of the highly toxic compound fentanyl and its analogues is increasing, raising serious public health concerns due to their potency and availability. Therefore, there is a need for decontamination methodologies to safely remove fentanyl to avoid harmful exposure. In this study, the efficacy of commercial and in-house synthesized decontamination agents (Dahlgren Decon, RSDL (Reactive Skin Decontamination Lotion), FAST-ACT (First applied sorbent treatment against chemical threats), GDS2000, alldecont MED, bleach, Domestos Spray Bleach, Effekt Klor, MgO, TiO2-nanodiamond, and CeO2) were evaluated for the degradation of fentanyl and carfentanil under controlled laboratory conditions and on wooden floor surfaces. Liquid chromatography/mass spectrometry analysis showed that oxidative decontamination agents were the most effective, with N-oxides identified as major degradation products. The physiological effects of these N-oxides were also investigated regarding their ability to activate the µ-opioid receptor and their metabolism in human liver microsomes. The results provide empirical evidence that complements prior research findings on the degradation of fentanyl and carfentanil using a variety of decontamination agents.

Catalytic Hydrolysis of Paraoxon by Immobilized Copper(II) Complexes of 1,4,7-Triazacyclononane Derivatives.

Organophosphate neuroactive agents represent severe security threats in various scenarios, including military conflicts, terrorist activities and industrial accidents. Addressing these threats necessitates effective protective measures, with a focus on decontamination strategies. Adsorbents such as bentonite have been explored as a preliminary method for chemical warfare agent immobilization, albeit lacking chemical destruction capabilities. Chemical decontamination, on the other hand, involves converting these agents into non-toxic or less toxic forms. In this study, we investigated the hydrolytic activity of a Cu(II) complex, previously studied for phosphate ester hydrolysis, as a potential agent for chemical warfare decontamination. Specifically, we focused on a ligand featuring a thiophene anchor bound through an aliphatic spacer, which exhibited high hydrolytic activity in its Cu(II) complex form in our previous studies. Paraoxon, an efficient insecticide, was selected as a model substrate for hydrolytic studies due to its structural resemblance to specific chemical warfare agents and due to the presence of a chromogenic 4-nitrophenolate moiety. Our findings clearly show the hydrolytic activity of the studied Cu(II) complexes. Additionally, we demonstrate the immobilization of the studied complex onto a solid substrate of Amberlite XAD4 via copolymerization of its thiophene side group with dithiophene. The hydrolytic activity of the resultant material towards paraoxon was studied, indicating its potential utilization in organophosphate neuroactive agent decontamination under mild conditions and the key importance of surface adsorption of paraoxon on the polymer surface.

Manganese metal ion removal from aqueous solution using industrial wastes derived geopolymer

Heavy metal pollutants, highly toxic and invisible, have garnered attention due to bioaccumulation. Increased manganese production from steel industries is expected to lead to harmful concentrations in water, adversely affecting the environment and public health. The sustainable approach of utilizing industrial by-products to synthesize geopolymers for the immobilization of heavy metal ions has gained research interest. The current study aims to verify the feasibility of Paper sludge ash (PSA) in conventional geopolymer (CGP) to immobilize manganese (Mn) heavy metal ions from aqueous solutions. CGP was prepared using Fly ash (FA) as resource material, which was replaced by PSA at a level of 30 %, by weight. The precursors were treated with alkali solutions, namely sodium hydroxide and sodium silicate, incorporating ambient curing. The characterization studies of precursors and CGP were investigated using XRD, XRF, SEM, EDS, FTIR, and Brunauer-Emmett-Teller surface area (BET) analysis techniques to outline the crystal structure, morphology, and pore parameters. Additionally, the experimental investigation comprehensively examined the impact of various pH levels, dosages, contact times, and initial concentrations on the removal efficiency of Mn heavy metal ions. The difference in concentration of Mn heavy metal ions quantified by atomic absorption spectrometry. The Langmuir models effectively explained the removal of Mn ions by CGP due to high fitting coefficients. The highest value of uptake capacity was found to be 28 mg/g at 30 °C with pH value of 4. Therefore, blending industrial wastes improves the potential of decontamination agents in removing heavy metals from wastewater, promoting environmental sustainability.

Cleaning the Electroerosive Machining Wastewater with some Polyacrylamide-Based Flocculants

The granulometric composition of the metal/scale suspensions formed at electroerosive machining (EEM) of metal items made of the ST-10 steel has been determined to evaluate the need for a flocculant for the suspension particles extraction and decontamination of the machining working fluid. Even though most suspension particles are large enough and quickly self-precipitate, some particles are too small (sized 6 µm or less) and form quite stable suspensions, requiring additional flocculants to be extracted. Pure polyacrylamide with a molecular weight of 4-5*106 atomic units and an anionic polymer flocculant BESFLOC-4041 were considered as decontamination agents for the metal/scale suspensions. It was found that the latter agent is more effective, and it ensures the effective decontamination of an EEM working fluid. An admixture of 0.05 g/L of BESFLOC-4041 ensures effective clarification (with the decontamination efficiency of 90-95 %) of the metal/scale suspension with a dispersed phase concentration of up to 1.0 g/L. The flocculation efficiency of polyacrylamimde is lower (67-85 %) and its best performance is achieved at the concentration of 0.08 g/L.

Evaluation of particle-capturing ability of a hydrogel-based surface decontamination agent using simulated nuclear fallout particles

Surface decontamination agents must effectively capture particle contaminants that have been deposited on surfaces. This ability is particularly important in scenarios involving nuclear fallout particles. In this technical note, the particle-capturing ability of a hydrogel, specifically, the polyvinyl alcohol-borax complex, was investigated as a potential decontamination agent for treating radioactively contaminated surface. For the assessment, simulated nuclear fallout particles, prepared by melting consolidation at 1200 °C followed by mechanical milling, were fixed on a stainless-steel substrate. The results demonstrated that the hydrogel effectively removed the simulated fallout particles from the surface. Even after only 1 min of contact time, the surface was left thoroughly clean, demonstrating the effectiveness of the polyvinyl alcohol-borax complex as a surface decontamination agent.

Model-based investigation of a novel decontamination technology: Ultrasound assisted aerosolized hydrogen peroxide

This work investigates the feasibility of a novel decontamination technology that employs ultrasonic acoustic streaming to improve aerosol distribution inside isolator chambers. For this purpose, a numerical model consisting of three simulations (i) acoustic pressure, (ii) fluid flow, and (iii) particle tracing, is developed. Acoustic air streaming is examined for ultrasound source pressure levels between 131 and 136 dB. Maximum streaming velocity reached values of the order 10−3 and 10−2m/s which agrees with previous experimental and numerical investigations. The effect of air velocity field on the deposition of the decontamination agent on the isolator floor was assessed for aerosol with droplet diameter between 10 and 20μm. The results show that a more homogeneous distribution of deposited droplets is obtained with configurations that have sound sources placed at a distance from each other. Designs with a homogeneous aerosol deposition are expected to have a better decontamination outcome.

Encapsulating carboxymethyl cellulose stabilized nanoscale ferrous sulfide with layered magnesium hydroxide shell for controlled reactivity release and long-term sequestration of Cr(Ⅵ)

Nanoparticulate iron sulfide (nano-FeS) is a highly effective and environmentally-friendly reducing agent for decontamination. However, challenges such as aggregation, poor mobility, and oxidative aging limit its application of in situ groundwater and soil remediation. Herein, we present a novel approach to enhance the feasibility and effectiveness of nano-FeS for in situ remediation by encapsulating carboxymethyl cellulose stabilized FeS nanoparticles with a layered magnesium hydroxide shell (referred to as CMC-FeS@Mg(OH)2). The novel CMC-FeS@Mg(OH)2 nanoparticles, with a suitable coating ratio (10 %–50 %), demonstrate considerably increased colloidal stability and enhanced mobility in porous media. This is mainly due to steric hindrance, and decreased attachment, blocking, and straining effects. The Mg(OH)2 shell obviously protects the reactivity of FeS nanoparticles and enhances their resistance to oxidation, ensuring their longevity and long-term decontamination effectiveness during practical field applications. The preserved reactivity of FeS core can be progressively released and fully recovered by modulating the Mg(OH)2 coating ration and the extent of dissolution. After the complete dissolution of the Mg(OH)2 shell, CMC-FeS@50 % Mg(OH)2 exhibits enhanced efficiency in Cr(VI) sequestration, increasing from 58 % to 92 % compared to bare FeS. The removal of Cr(VI) by CMC-FeS@Mg(OH)2 is a synergistic process, and the main mechanisms includes adsorption, reduction, ion exchange, and subsequent precipitation. These results demonstrate a promising and effective method to improve the mobility and longevity of FeS and enable the controlled reactivity release for in situ remediation of subsurface contamination.

Decontaminants Used After Biorisk Material Decontamination: Environmental Impact and the Role of Drones in Detection and Remediation of Resistance in Ecosystems

In our rapidly evolving world, the confluence of challenges and opportunities in decontamination, ecological resilience, and cutting-edge technology has become a focal point of concern and innovation. This review explores the interplay between these elements, with profound implications for human safety and environmental equilibrium. Post-decontamination treatment is pivotal in countering Chemical, Biological, Radiological, and Nuclear (CBRN) hazards. Thorough contamination elimination is imperative for risk management. The emergence and proliferation of resistance within ecosystems present a complex challenge. Resistance mechanisms can thwart decontamination agents, affecting environmental restoration, human health, and ecological resilience. Drone technology heralds a transformative era in environmental monitoring. Drones with advanced sensors and data capabilities provide access to remote, hazardous, and inaccessible ecological areas. Real-time data empowers researchers to adapt to evolving conditions, including resistance dynamics. Drones also serve as tools for targeted remediation in contaminated areas, optimizing resource allocation and minimizing disruption. Case studies highlight their efficacy in ecological restoration. Integrating drones into post-decontamination protocols is a paradigm shift. Real-time data, facilitated by drones, bridges the gap between ecological understanding and strategic action. In conclusion, safeguarding our world is a collective responsibility. Drones symbolize our commitment to harmonizing human needs with the environment. This review illuminates a path forward, celebrating our capacity to protect, preserve, and prosper, not just for ourselves but for the world we inhabit. It emphasizes the imperative to save our planet, forging a sustainable future where humanity and nature thrive in harmonious coexistence.

Efficacy of a Solution Containing 33% Trichloroacetic Acid and Hydrogen Peroxide in Decontaminating Machined vs. Sand-Blasted Acid-Etched Titanium Surfaces.

This in vitro study assessed the efficacy of a solution containing 33% trichloroacetic acid (CCl3COOH; TCA) and hydrogen peroxide (H2O2) in decontaminating machined (MAC) and sand-blasted acid-etched (SBAE) titanium surfaces. A total of 80 titanium disks were prepared (40 MAC and 40 SBAE). Streptococcus sanguinis and Enterococcus faecalis strains were incubated on 36 samples, while the remaining 44 were kept as controls. Roughness analysis and scanning electron microscopy were used to evaluate the surface features before and after TCAH2O2 treatment. The viability of human adipose-derived mesenchymal stem cells (ASCs) after TCAH2O2 decontamination was assessed with a chemiluminescent assay along with cell morphology through fluorescent staining. TCAH2O2 preserved the surface topography of MAC and SBAE specimens. It also effectively eradicated bacteria on both types of specimens without altering the surface roughness (p > 0.05). Also, no significant differences in protein adsorption between the pristine and TCAH2O2-treated surfaces were found (p = 0.71 and p = 0.94). While ASC proliferation remained unchanged on MAC surfaces, a decrease was observed on the decontaminated SBAE specimens at 24 and 48 h (p < 0.05), with no difference at 72 h (p > 0.05). Cell morphology showed no significant changes after 72 h on both surface types even after decontamination. This study suggests TCAH2O2 as a promising decontamination agent for titanium surfaces, with potential implications for peri-implant health and treatment outcomes.

Insights into performances of magnetic and bio-based doped-nanohydroxyapatites as water decontamination agents

Nanohydroxyapatites functionalized with iron and bio-based substances extracted from green compost show good adsorption and antimicrobial properties.

Photodynamic Inactivation of Bovine Coronavirus with the Photosensitizer Toluidine Blue O.

Coronaviruses (CoVs) belong to the group of enveloped positive-sense single-strand RNA viruses and are causative agents of respiratory, gastro-intestinal, and central nervous systems diseases in many host species, i.e., birds, mammals, and humans. Beta-CoVs revealed a great potential to cross the barrier between species by causing three epidemics/pandemics among humans in the 21st century. Considering the urgent need for powerful antiviral agents for decontamination, prevention, and treatment of BCoV infections, we turned our attention to the possibility of photodynamic inactivation with photosensitizers in combination with light irradiation. In the present study, we evaluated, for the first time, the antiviral activity of toluidine blue O (TBO) against Beta-coronavirus 1 (BCoV) in comparison to methylene blue (MB). First, we determined the in vitro cytotoxicity of MB and TBO on the Madin-Darby bovine kidney (MDBK) cell line with ISO10993-5/Annex C. Thereafter, BCoV was propagated in MDBK cells, and the virus titer was measured with digital droplet PCR, TCID50 assay and plaque assay. The antiviral activity of non-toxic concentrations of TBO was estimated using the direct inactivation approach. All effects were calculated in MAPLE 15® mathematical software by developing programs for non-linear modeling and response surface analysis. The median inhibitory concentration (IC50) of TBO after 72 h of incubation in MDBK cells was 0.85 µM. The antiviral activity of TBO after the direct inactivation of BCoV (MOI = 1) was significantly stronger than that of MB. The median effective concentration (EC50) of TBO was 0.005 µM. The cytopathic effect decreased in a concentration-dependent manner, from 0.0025 to 0.01 µM, and disappeared fully at concentrations between 0.02 and 0.3 µM of TBO. The number of virus particles also decreased, depending on the concentration applied, as proven by ddPCR analysis. In conclusion, TBO exhibits significant potential for direct inactivation of BCoV in vitro, with a very high selectivity index, and should be subjected to further investigation, aiming at its application in veterinary and/or human medical practice.

Evaluation of Shear Bond Strength of Resin Cement on the Surface of a Lithium Disilicate Glass-Ceramic Restorative Material after Various Surface Treatments

With bonded restorations gaining rapid popularity in clinical dentistry, manufacturers have introduced a variety of bonding protocols and materials. These materials, including surface modifiers and cleaning agents, are designed to decontaminate surfaces and enhance bonding effectiveness. In this study, six different combinations of mechanical and chemical modifications were tested on a lithium disilicate surface to determine the combination that offers optimal resistance to shear stresses. The tested surface modifications included 9% hydrofluoric acid, sandblasting with 29 μm aluminum oxide (Al2O3) particles, Ivoclean (a recently introduced decontamination agent), Monobond Etch &amp; Prime (a one-stage etching and priming agent for ceramic surfaces), Monobond Plus (a silane agent), and the bonding agent Adhese Universal. Six different sequence combinations were tested and compared to the negative control group. The highest bond strength was achieved using all materials and cleansing methods in a logical order, while the bond strength was lowest in the absence of surface modification (control group). The results indicate a significantly positive influence on bond strength of silane coupling agents present in surface modifiers, including pure forms like Monobond Plus. Potential negative effects of cleansing agents or methods on bond strength were not observed. Multiple and separate stages in the treatment of the lithium disilicate surface positively impact bond strength. Cleansing agents may prove beneficial in clinical conditions, and they do not interfere with bonding.

Effects of EDTA on the leaching behaviors of Cs(I) and Co(II) from cement waste forms

Cementation is extensively employed for immobilizing radionuclides in low- and intermediate-level radioactive wastes generated during the decommissioning of nuclear power plants. Ethylenediaminetetraacetic acid (EDTA), used as a decontamination agent during the decommissioning process, can be introduced into the cement waste form containing radionuclides. This study investigated the effects of the EDTA present in simulated radioactive decommissioning wastes on the leaching behaviors of Co and Cs immobilized in the cement waste form. Co leaching was facilitated by the formation of highly mobile Co–EDTA complexes. However, Cs leaching was impeded by the competition for leaching with other metal–EDTA complexes. Moreover, the EDTA-induced carbonated layer with a dense pore structure played a crucial role as a retardation barrier for the Cs leaching. The calcite contents of the samples with 8 wt% EDTA were approximately three times higher than those of the samples without EDTA. The introduced EDTA affected the leaching behaviors of both Co and Cs, as well as the microstructure evolution of the cement waste form. Nevertheless, the addition of EDTA had a relatively low positive effect on the efficiency of Cs immobilization, but also an obvious negative effect on the efficiency of Co immobilization, regardless of the concentration of EDTA. Finally, an EDTA dosage of 1 wt% in the cement waste forms containing Co or Cs is suggested as a potential waste acceptance criterion for solidified low- and intermediate-level radioactive waste.

Fabrication of nanofibrous PbO2 electrode embedded with Pt for decomposition of organic chelating agents

A new fabrication method of nanofibrous metal oxide electrode comprising Pt nanofiber (Pt–NF) covered with PbO2 on a Ti substrate was proposed. Pt–NF was obtained by performing sputtering deposition of Pt on the surface of electrospun poly(vinyl alcohol) (PVA) nanofiber on a Ti substrate, in which PVA was then removed by calcination (Ti/Pt–NF). Subsequently, by introducing PbO2 to the Ti/Pt–NF using the electrodeposition method, a nanofibrous Ti/Pt–NF/PbO2 electrode was finally obtained. Because the Ti substrate was covered by nanofibrous Pt, it had no environmental exposure and thus, was not oxidized during calcination. The crystal structure of the PbO2 mainly consisted of β-form rather than α-form; the β-form was suitable for electrochemical decomposition and remained stable even after 20 h of use. The nanofibrous Ti/Pt–NF/PbO2 electrodes showed 10% lower anode potential, 1.6 times higher current density at water decomposition potential, lower electrical resistance in the ion charge transfer resistance, and 2.27 times higher electrochemically active surface area than those of a planar-type Ti/Pt/PbO2 electrode, and demonstrated excellent electrochemical performance. As a result, compared with the planar electrode, the Ti/Pt–NF/PbO2 electrode showed more effective electrochemical decomposition toward nitrilotriacetic acid (80%) and ethylenediaminetetraacetic acid (83%), which are commonly used as chelating agents in nuclear decontamination.

EFFICACY OF A DCBRN-01VN SKIN DECONTAMINANT ON ANIMALS EXPOSED TO 2-CHLOROETHYL ETHYL SULFIDE

Chemical warfare agents are an actual threat and decontamination for victims is a main concern when mass exposure occurs. The study evaluated the effectiveness of the skin decontamination agent DCBRN-01VN based on the oxime compound KBDO for CEES (2-chloroethyl ethyl sulfide). HPLC analysis method was used to determine the temperature after decontamination in vitro and in vivo tests and then to check biochemical and hematological indicators in rats. The test results show that DCBRN-01VN has a high efficiency of CEES decontamination, in vitro: with the ratio of CEES: decontaminant 1:20 in 10 minutes reaching 55.04%, with the ratio 1:10 in 20 minutes reached 55.95%, in 30 minutes reached 82.93%, in 60 minutes reached nearly 100%; in vivo test with a ratio of 1:15 in 20 minutes reached almost 100%. Results of biochemical and hematological examination showed no difference between the negative control group and two experimental groups (with decontamination and without decontamination) P(2-1) &gt; 0.05; P(3-1) &gt; 0.05. Histopathological analysis showed that decontamination also reduced damage caused by CEES.

Effect of Different Decontamination Agents on The Bond Strength of CAD/CAM Blocks and Repair Composite Materials

The purpose of this study was to examine the effect of different decontamination agents on the bond strength of saliva-contaminated CAD/CAM blocks and repair composite materials. Two hunderd eighty 3-mm-thick specimens were prepared from four different CAD/CAM materials: Katana Zirconia UTML disc, IPS e.max CAD block, Shofu block, and Vita Enamic block. Each material was divided into seven different subgroups (N=70). Group 1 had a clean surface. The other groups were comprised of the samples, which were contaminated with human saliva: group 2: negative control (non-cleaned); group 3: cleaned with water spray; group 4: cleaned with 70% ethanol; group 5: cleaned with Ivoclean; group 6: cleaned with Katana Cleaner; and group 7: cleaned with phosphoric acid. After the decontamination protocols, the resin composite cylinders were bonded to the CAD/CAM surfaces with a thin layer of dual-cured resin cement. The samples were stored for 24 hours at 37°C in distilled water. Then, they were subjected to a shear bond strength test (SBS). The values were recorded, and fracture types were evaluated using a microscope. Data were analyzed using two-way ANOVA and Tukey’s post-hoc test. Generally, all decontaminating agents improved the SBS of composites to Katana Zirconia UTML, IPS e.max, and Vita Enamic materials (p&lt;0.05). However, for Shofu materials, group 6 samples exhibited significantly higher bond strength values as compared with group 2 samples (p=0.026). The highest SBS values were seen in the phosphoric acid-treated group in Katana zirconia materials (26.45 ± 9.38 MPa), whereas the lowest values were seen in group 2 samples in Shofu materials (13.17 ± 3.40 MPa). Each decontaminant agent improved the bond strength of composites to the contaminated CAD/CAM materials. If saliva is not cleaned before adhesive procedure, SBS values may decrease. All decontamination agents can be used safely on zirconia, lithium-disilicate glass-ceramic, hybrid ceramic, and polymer-infiltrated ceramic surfaces.

A Study to Evaluate the Effect of Cleaning Solutions on Shear Bond Strength of Resin Cement to Saliva-Contaminated Lithium Disilicate (LDS) Ceramic.

One of the greatest benefits of contemporary restorative dentistry is the creation of fixed partial dentures. The retention and durability of the fixed partial dentures may be improved by using a variety of tooth preparation methods, surface treatments, and luting resins. To measure the shear binding strength of resin cement to saliva-contaminated lithium disilicate (LDS) ceramicafter being exposed to various cleaning treatments. Over 30 LDS samples were examined. In Group 1, a cleansing solution comprising 15% zirconium oxide (Ivoclean) was employed for a duration of 20 s. This was succeeded by a rinsing phase lasting 15 s utilizing deionized water, followed by a 15-s period for drying. Subsequently, a final stage of air drying was conducted over a span of 15 s.In contrast, Group 2 underwent a washing procedure of 20 s involving a cleansing solution containing 30% sodium silicate. This was then ensued by a rinsing interval of 15 s with deionized water, succeeded by an air-drying process spanning 15 s. After applying cleaning solutions to the surface and adhering the specimens to the composite blocks using resin cement Multilink Automix (Ivoclar Vivadent, Schaan, Liechtenstein), the shear bond strength was assessed. Using a 30% sodium silicate solution (Group 2), we were able to get the highest mean shear bond strength value after saliva-contaminated LDS. Group 1, 15% zirconium oxide (Ivoclean) had the weakest decontamination agents as measured by mean shear bond strengths. The shear bond strength values of the two groups were found to vary significantly between individuals using the independent sample t-test. LDs ceramic cleaned with a 30% sodium silicate solution had a higher shear bond strength than ceramic cleaned with Ivoclean (p<0.05). The application of a 30% sodium silicate solution rendered the highest shear bond strength for saliva-contaminated LDS ceramic. In comparison, ceramic cleaned with Ivoclean exhibited notably lower shear bond strength values. The outcome of this investigation highlights the potential of diverse cleaning agents in influencing the adhesive qualities of resin cement, thereby contributing to the enhancement of fixed partial denture durability and efficacy.

Escherichia coli virulence inhibition by cell-free supernatants from mangrove forest bacteria producing quorum sensing inhibitor

Escherichia coli is a major concern in the food industry because of its ability to produce biofilm causing food contamination. Autoinducer 2 (AI-2) in E. coli is used to regulate quorum sensing (QS) which controls its physiological functions and pathogenicity, especially biofilm formation. Inhibition of the QS is an alternative decontamination approach in the food industry. In this study, 9 bacterial strains isolated from mangrove forests demonstrated their ability to inhibit the bioluminescent production of Vibrio campbellii biosensor strain. Bacteria were identified and Staphylococcus warneri was chosen for further characterization. The minimum inhibitory concentration (MIC) of the cell-free supernatant (CFS) extract against E. coli ATCC 25922 was 25 mg/mL. The CFS extract at 1/2- and 1/4-MIC showed 70–100% and 28–62% biofilm reduction against biofilm-forming E. coli, respectively. The reduction of biofilm and cell attachment was observed under SEM. LC/MS analysis demonstrated that 21 compounds were identified and the active compound on the QS will further be investigated in future research. From our study, we concluded that S. warneri isolated from mangrove forests can produce bioactive compounds interfering QS system, inhibiting E. coli biofilm and demonstrating the potential to develop a novel biocontrol agent for decontamination of biofilm-forming bacteria contaminated in food production.

Adsorption of Rhodamine B and Pb(II) from aqueous solution by MoS2 nanosheet modified biochar: Fabrication, performance, and mechanisms

Mediated by polydopamine, MoS2 nanosheets were immobilized on the porous biochar derived from fungus residue, forming a novel biochar-based nanocomposite (MoS2–PDA@FRC) for the removal of Rhodamine B(RhB) and Pb(II) from water. Utilizing MoS2 nanosheets with abundant active adsorption sites, MoS2–PDA@FRC showed higher adsorption capacities than raw biochar, with 2.76 and 1.78 times higher capacities for RhB and Pb(II) respectively. MoS2–PDA@FRC also exhibited fast adsorption kinetics for RhB (120 min) and Pb (180 min) removal, as well as satisfactory adsorption selectivity in the presence of coexisting substances. The underlying removal mechanism was explored via Fourier transform infrared and X-ray photoelectron spectroscopies. Furthermore, during cyclic adsorption–regeneration and the fixed-bed adsorption experiments, the nanocomposite removed RhB and Pb(II) with high effectiveness and stability. Collectively, the results demonstrated the bright prospects of MoS2–PDA@FRC as a highly efficient decontamination agent of RhB and Pb(II) from water.

Selected decontamination methods of chemical warfare agents covered by the Chemical Weapons Convention

Decontamination is the overall physicochemical process leading to completely neutralising or weaken-ing the toxic properties of poisonous substances. In the literature, there are many ways to eliminate con-tamination, including more through innovative methods. The decontamination agents known and used so far have been thoroughly tested in terms of interaction with chemical warfare agents (CWA), espe-cially relating to kinetics and the resulting reaction products. However, with the extension of the Chem-ical Weapons Convention to new substances, i.e., compounds of the “A” series, the so-called No-vichoks, their interaction with available decontamination agents is a subject to verification. On the other hand, equally important, new substances find decontaminating applications; therefore, it seems crucial to test them comprehensively regarding their impact on toxic substances. In this paper, selected methods of decontamination of chemical warfare agents are reviewed, together with the experimental results of the conducted research. The main effort was focused on discussing the most essential decontamination agents known so far. Also, attention was paid to new methods of decontamination that have not yet been introduced to common use but only tested in the laboratory for the possibility of use as a decon-tamination agent.Keywords: chemical warfare agents, decontamination, decontamination agents analytical chemistry