Decontamination Process Research Articles

Fe3O4@Fe2O3 carbon aerogel particle electrodes for three-dimensional electro-Fenton oxidation: A novel mechanism promoted by non-radical pathway

Three-dimensional electro-Fenton (3D-EF) has exhibited strengths over traditional electro-Fenton (EF) process for water decontamination, but recent researches on 3D-EF are focused on the decontamination mechanism driven by the radical pathway which was environmentally sensitive and poor in anti-interference capability. This study explored the non-radical mechanism in the 3D-EF process by preparing a novel Fe3O4@Fe2O3/carbon aerogel-700 (FFCA-700) particle electrode (PE) to construct a 3D-EF system promoted by non-radical pathway. The electrodes induced electric field spontaneously polarized FFCA-700 into PEs which led to higher active surface areas of electrodes and the enhancement of mass transfer. Numerous polarized FFCA-700 served as electron donor for dissolved O2 to obtain electron to form ·O2– while the increase in positive charge of the graphitized carbon, caused by the functional group containing electron-rich oxygen, was conducive for ·O2– to transform to 1O2 thus promoting the non-radical pathway. Tetracycline (TC) was selected as the model pollutant to evaluate and compare the remediation performance of different systems. The results suggested that FFCA-700-3D-EF system performed well for pollutant removal in real wastewater. Overall, this study provided a reference for the design and optimization of CPEs and the guidance for the mechanism studies on remediation of organically contaminated wastewater by 3D-EF process.

Removal of Surface Radioactive Uranium(Ⅵ) by Graphene Oxide Modified κ-carrageenan/Konjac Glucomannan Composite Hydrogel

Hydrogel is an effective surface decontamination technology. However, traditional colloid decontaminants face a long curing time and low decontamination rate. A peelable hydrogel coating composed of carrageenan, konjac glucan, and graphene oxide with excellent film-forming performance and decontamination efficiency was explored in this study. The results showed that the graphene oxide was effectively dispersed inside the hydrogel, improving the crosslink density and thermal stability of the hydrogel by forming hydrogen bonds with polysaccharide molecules. The graphene oxide can effectively enhance the decontamination performance of the hydrogel. For stainless steel, ceramic, glass, and rubber surfaces, the decontamination rates of the hydrogel for 30min were 96.95%, 87.6%, 96.27%, and 74.5%, respectively. The decontamination effect was stable to temperature. For cement surfaces, the hydrogel could reach a maximum decontamination rate of 70.68% after 24h. The decontamination efficiency of hydrogel was affected by porosity, surface roughness, and graphene oxide addition. The characterization results of XPS, FT-IR, and SEM/EDS showed that the decontamination process of the composite hydrogel may involve surface wetting, ion diffusion, electrostatic attraction, and physical entanglement.

Optimisation of plasma processes for decontamination of bacterial contaminants on polymeric food packaging materials

Abstract Foodborne diseases present a global health challenge, with over 420 000 deaths annually. Packaging plays a vital role in food safety but can introduce hazards if contaminated. Traditional decontamination methods are energy-intensive or leave toxic residues. Cold plasma technology offers promising solutions for generating antimicrobial reactive species. This study optimises a plasma system for packaging decontamination, achieving high inactivation rates for Staphylococcus epidermidis (gram-positive) and Acinetobacter baumannii (gram-negative), respectively 3.5 and 4.7. Statistical analysis guide process optimisation, highlighting factors enhancing biocidal action: treatment chamber size reduction, high duty cycle, and mist injection. The system proves effective against both kinds of bacteria, with gram-negative bacteria showing higher sensitivity. The study focuses on optimising an innovative process, emphasising the process towards industrialisation and highlighting economic and environmental benefits. This investigation’s innovative approach aims to bridge the gap between laboratory prototypes and industrial applications.

ETIOPATHOGENETIC MECHANISMS OF IMMUNE DYSFUNCTION IN COMBATANTS WITH LOWER LIMB SOFT TISSUE INJURIES UNDER CHRONIC STRESS

Introduction. Combat injuries, including gunshot, shrapnel, and mine-explosive wounds, affect a significant number of soldiers in modern warfare. Notably, most of these injuries involve damage to the soft tissues of the extremities. Surgeons have expressed concerns regarding the unsatisfactory treatment outcomes in this group of combatants, attributing one of the primary challenges to the limited understanding of immune dysfunction pathogenesis in military trauma cases. This study aims to address this gap by examining immune system dysfunctions in combat-related injuries. The objective of this study is to thoroughly analyze and synthesize the key stages of immune dysfunction occurring over extended periods post-combat trauma, including the subsequent development of traumatic disease and various wound complications. Materials and Methods. The rising prevalence of combat trauma among soldiers has intensified interest in studying this issue, prompting surgeons and traumatologists to address its various medical aspects comprehensively. The literature search focused on recent publications, allowing for a targeted analysis of the immunological aspects relevant to military medical traumatology. Results. In the initial stages of severe or combined injuries affecting various tissues—such as tubular bones, joints, blood vessels, and peripheral nerves—systemic inflammatory response syndrome (SIRS) commonly occurs. This stage is marked by an intense activation of innate antibacterial and immune-protective responses, leading to a significant increase in inflammation. This initial response is soon replaced by a prolonged phase known as compensatory anti-inflammatory response syndrome. During this period, immune-protective responses sharply decrease, certain immunocompetent cells become inhibited, and lymphopenia develops. This phase is often accompanied by infectious contamination of wounds with pathogenic and opportunistic microorganisms, resulting in both local purulent-necrotic processes and potentially severe systemic complications, such as septic shock, sepsis, multiple organ failure, and others. The final stage, known as persistent inflammatory, immunosuppressive, catabolic syndrome, is characterized by the chronic progression of traumatic disease, accompanied by ongoing immune system dysfunction in combatants. Conclusion. In the early period of traumatic injury, the wounded experience sharp inflammatory processes and activation of immune defense mechanisms. At subsequent stages, severe disruptions in the functioning of the immune system, damage to internal organs, and the development of catabolic syndrome are recorded. These changes, especially those resulted from exposure to chronic combat stress preceding the injury, aggravate the processes of infectious decontamination of wounds, regeneration of damaged tissues, and the general process of combatant rehabilitation.

Enhancing water circularity: Lactic acid-menthol deep eutectic solvent for efficient fats, oils and grease (FOG) removal and recovery from contaminated waters

Water pollution, particularly the contamination of water sources by fats, oils, and grease (FOG), presents a significant environmental challenge exacerbated by climate change. While conventional water resource recovery facilities (WRRFs) address various contaminants, FOG treatment often remains indirect and suboptimal. This study introduces an innovative, environmentally benign approach utilizing deep eutectic solvents (DESs) for the targeted removal and recovery of FOG from contaminated waters via liquid-liquid extraction. A binary DES comprising menthol and lactic acid was synthesized and evaluated for its efficacy in extracting oleic acid, selected as a model fatty acid contaminant. The investigation employed a comprehensive factorial design to optimize key operational parameters, including the molar ratio of DES components, solvent-to-water ratio, contact time, initial contaminant concentration, stirring speed, and phase separation time. Results demonstrated exceptional removal efficiencies exceeding 95 % under optimized conditions, with peak performance approaching 99.5 %. Optimal parameters were identified as a 1:1 molar ratio of menthol to lactic acid, 1:10 DES-to-water ratio, 15-minute contact time, 300 mg L⁻¹ initial contaminant concentration, 500 RPM stirring speed, and 8-hour phase separation. This research establishes a foundation for the application of DESs in water decontamination processes, potentially revolutionizing FOG management and advancing water circularity initiatives. The study's findings align with multiple UN Sustainable Development Goals, including SDG 6 (Clean Water and Sanitation), SDG 14 (Life Below Water), and SDG 12 (Responsible Consumption and Production), offering a promising avenue for sustainable water treatment technologies.

Potencial bioindicador de mudas de Cedrela fissilis em áreas contaminadas por cobre

ABSTRACT Soil contamination with toxic metals brings along severe environmental issues. Among these metals, copper (Cu) is harmful to plant development when it reaches high contamination levels in the soil. Thus, identifying species capable of resisting this contamination type helps these sites’ revegetation and decontamination processes. Therefore, the present study aimed to investigate the tolerance of Cedrela fissilis plants to excess Cu through morphophysiological and biochemical variables. C. fissilis seedlings were subjected to five concentrations of Cu (0, 2, 4, 6, and 8 mg L-1). The experimental design was completely randomized, with five treatments and four repetitions. Morphophysiological (number of leaves, shoot height, root length, dry weight, morphological variables of the root system, and leaf area) and biochemical (antioxidant enzymes, lipid peroxidation, hydrogen peroxide concentration, and photosynthetic pigments) traits and Cu accumulated in roots and shoot were evaluated. High concentrations of Cu had a negative effect on the shoot and root dry weight, photosynthetic rate, stomatal conductance, and transpiration rate. Overall, Cu increased the activity of the antioxidant enzymes and lipid peroxidation. Therefore, Cu incidence in the nutrient solution has negatively influenced the biochemical and physiological traits of C. fissilis seedlings to the detriment of their growth. Thus, it was possible to identify sensitive behavior by the investigated species. Because of these features, C. fissilis seedlings can be used as markers for copper-contaminated areas.

Investigation into the purification and regeneration of rare earth polishing powder waste via continuous solid-phase conversion

The concentration of rare earth elements (lanthanum, cerium, and praseodymium) within rare earth polishing powder waste (REPPW) typically exceeds 50 %, with the majority of impurities comprised of silicon and aluminum-related compounds. Transforming REPPW into recycled rare earth polishing powders that adhere to polishing standards in an eco-friendly and economically viable way presents a significant challenge in the industry. Traditional acid or alkaline processes predominantly recover rare earth elements as oxides, which are underutilized due to their high costs. Considering the varying forms of impurities and rare earth compounds found in REPPW, this research introduces a novel physicochemical decontamination and continuous chemical transformation process aimed at producing regenerated rare earth polishing powders. Under optimal conditions, the physicochemical two-step decontamination process achieved a rare earth recovery rate surpassing 92 %, while silicon and aluminum removal rates reached 86.12 %. During the continuous chemical transformation of REPPW, the rare earth phases in an alkaline setting followed the sequence REOF (CeO2) → RE(OH)3 → RECO3OH→RECO3F→CeLa2O3F3(CeO2), which not only facilitated phase reorganization but also enhanced the particle surface structure. Notably, these chemical transformations did not disrupt the rare earth distribution; instead, they indirectly boosted product purity and uniformly dispersed within the regenerated polishing powder particles, thereby improving polishing efficiency. Consequently, the adoption of this innovative regeneration process for polishing powders holds substantial importance for the sustainable utilization of rare earth resources.

Long-term spatiotemporal changes in nitrate contamination of municipal groundwater resources after sewerage network construction in the Hungarian Great Plain.

Over the last decades, as a consequence of wastewater discharges and other anthropogenic sources, severe nitrate (NO3-) pollution has developed in municipal environment causing global concern. Thus, eliminating the potential sources of pollution is one of the major challenges of the twenty-first century, whereby sanitation services are essential for ensuring public health and environmental protection. In the present study, long-term monitoring (2011-2022) of shallow groundwater NO3- contamination in municipal environment was carried following the construction of the sewerage network (2014) in the light of the pre-sewerage situation. Our primary aim was to assess the long-term effects of sewerage on nitrate NO3- levels in the shallow groundwater and evaluate the efficiency of these sanitation measures over time. Based on the results, significant pollution of the shallow groundwater in the municipality was identified. During the pre-sewer period, NO3- concentrations exceeded the 50mg/L limit in the majority of monitoring wells significantly, upper quartile values ranged between 341 and 623mg/L respectively. Using Nitrate Pollution Index (NPI) and interpolated NO3- pollution maps, marked spatial north-south differences were detected. In order to verify the presence of wastewater discharges in the monitoring wells, the isotopic ratio shifts (δ) for 18O and D(2H) were determined, confirming municipal wastewater effluent. Variations in NO3-/Cl- molar ratios suggest also contamination from anthropogenic sources, including septic tank effluent from households and the extensive use of manure. Data series of 7years (2015-2022) after the investment indicate marked positive changes by the appearance of decreasing trends in NO3- values confirmed by Wilcoxon signed rank test and ANOVA. By comparing the pre- and post-sewerage conditions, the mean NO3- value decreased from 289.7 to 175.6mg/L, with an increasing number of monitoring wells with concentrations below the limit. Our results emphasise the critical role of sanitation investments, while also indicating that the decontamination processes occur at a notably slow pace. Detailed, long-term monitoring is therefore essential to ensure accurate follow-up of the ongoing changes. The results can provide information for local citizens and authorities to improve groundwater management tools in the region.

A method for decontaminating a dental implant and components after abutment screw loosening: A clinical report

Abutment screw loosening is the most common complication in single implant-supported crowns, typically remedied by simply reattaching the restoration, preferably using a new abutment screw. The internal aspect of the implant along with any other components should be decontaminated before reconnection. This clinical report provides information on the appropriate management of the decontamination process, as well as evidence of the foreign material found within the implant body.

Nuclear Decommissioning and Sustainable Environment: Insights on Decontamination Processes

Nuclear energy accounts for ≈10% of global energy production, positioning it as a promising solution for achieving carbon neutrality amid escalating concerns over climate change. Nonetheless, the effective management of radioactive waste, which can remain hazardous for up to one hundred thousand years, presents considerable challenges that must be addressed to uphold public trust and safeguard environmental safety. This review outlines the fundamental stages of nuclear decommissioning including strategic planning, decontamination, dismantling, remediation, encapsulation, deregulation, and site reuse as a critical component of sustainable environmental practices. The review also highlights the significance of efficient decontamination processes in reducing waste generation. Various decontamination techniques, including mechanical, electromechanical, chemical, and advanced methods such as laser and plasma decontamination, are evaluated for their effectiveness and limitations. Moreover, the review emphasizes the need to enhance the recovery and recycling of ion exchange resin and potential radionuclides during decontamination processes to minimize waste and to address the depletion of potential radionuclide resources. Future research should prioritize the development of innovative techniques for decontamination and radioactive waste management, fostering sustainable decommissioning and supporting the ongoing development of nuclear energy in an environmentally responsible manner.

Comprehensive Insight into the Common Organic Radicals in Advanced Oxidation Processes for Water Decontamination.

Radical-based advanced oxidation processes (AOPs) are among the most effective technologies employed to destroy organic pollutants. Compared to common inorganic radicals, such as •OH, O2•-, and SO4•-, organic radicals are widespread, and more selective, but are easily overlooked. Furthermore, a systematic understanding of the generation and contributions of organic radicals remains lacking. In this review, we systematically summarize the properties, possible generation pathways, detection methods, and contributions of organic radicals in AOPs. Notably, exploring organic radicals in AOPs is challenging due to (1) limited detection methods for generated organic radicals; (2) controversial organic radical-mediated reaction mechanisms; and (3) rapid transformation of organic radicals as reaction intermediates. In addition to their characteristics and reactivity, we examine potential scenarios of organic radical generation in AOPs, including during the peroxide activation process, in water matrices or with coexisting organic pollutants, and due to the addition of quenching agents. Subsequently, we summarize various methods for organic radical detection as reported previously, such as electron paramagnetic resonance spectroscopy (EPR), 31P nuclear magnetic resonance spectroscopy (31P NMR), liquid/gas chromatography-mass spectroscopy (GC/LC-MS), and fluorescence probes. Finally, we review the contributions of organic radicals to decontamination processes and provide recommendations for future research.

An enhanced electrokinetic system for remediation of Cu-polluted clay soils by integrating purging solutions and intermittent power

This study investigated the effectiveness and underlying mechanisms of purging solutions enhanced by intermittent power in improving electrokinetic (EK) restoration of clay soils even under high levels of heavy metals (HM). In so doing, the artificially contaminated specimens containing a wide range of copper (Cu) were prepared and then subjected to a series of EK tests with various electrolytes and electric regimes. Macro and micro scale examinations revealed that under the unenhanced EK condition (i.e., continuous current without agents), the formation of non-conducting solid phases and/or the clogged fabric in the samples with the high dosages (> 250 mg/kg) of HM could dramatically impede the metal separation from the soil. Hence, increasing the remediation time would not be very effective in facilitating the decontamination process. It was observed that the EDTA-ameliorated treatment accompanied by pentetic acid and acetic acid can mitigate the metal precipitation/encapsulation effects induced by EK actions, resulting in improved rate of HM removal. In this case; however, a high portion of these enhancers would be required to ensure the stable mobility of ions and to achieve successful recovery. Such a limitation has been shown to be overcome by incorporating pulsed power (PP) at an optimal frequency. In fact, as evidenced by SEM-EDX and XRD analyses, the integration of chemical agents with PP could simultaneously retain the solubilized Cu species in the soil mass and modify the matrix tortuosity (i.e., the establishment of well-linked pores), two features that have been found to play essential roles in providing for favorable activity of HM ions during the EK operation. The corresponding refinements in the binary system would cause an almost 8 folds increase in the removal efficiency and a shorter (up to 30 %) time of treatment compared to conventional EK.

Selective O2-to-H2O2 Electrosynthesis by a High-Performance, Single-Pass Electrofiltration System Using Ibuprofen-Laden CNT Membranes.

Producing H2O2 through a selective, two-electron (2e) oxygen reduction reaction (ORR) is challenging, especially when it serves as an advanced oxidation process (AOP) for cost-effective water decontamination. Herein, we attain a 2e-selectivity H2O2 production using a carbon nanotube electrified membrane with ibuprofen (IBU) molecules laden (IBU@CNT-EM) in an ultrafast, single-pass electrofiltration process. The IBU@CNT-EM can generate H2O2 at a rate of 25.62 mol gCNT-1 h-1 L-1 in the permeate with a residence time of 1.81 s. We demonstrated that an interwoven, hydrophilic-hydrophobic membrane nanostructure offers an excellent air-to-water transport platform for ORR acceleration. The electron transfer number of the ORR for IBU@CNT at neutral pH was confirmed as 2.71, elucidating a near-2e selectivity to H2O2. Density functional theory (DFT) studies validated an exceptional charge distribution of the IBU@CNT for the O2 adsorption. The adsorption energies of the O2 and *OOH intermediates are proportional to the H2O2 selectivity (64.39%), higher than that of the CNT (37.81%). With the simple and durable production of H2O2 by IBU@CNT-EM electrofiltration, the permeate can actuate Fenton oxidation to efficiently decompose emerging pollutants and inactivate bacteria. Our study introduces a new paradigm for developing high-performance H2O2-production membranes for water treatment by reusing environmental functional materials.

The Decontamination of N95 Masks as an Occupational Safety Strategy

Objective: This study aimed to monitor the use of a short-wave ultraviolet (UV-C) decontamination device for N95 masks at the João de Barros Barreto University Hospital, Belém, Pará, Brazil. The research investigated the reuse of masks, storage methods, and the perception of healthcare professionals regarding the decontamination protocol using UV-C after each work shift. Theoretical Framework: The research is based on theories related to biosafety and occupational health, focusing on the importance of decontamination processes in hospital settings to enhance the protection of healthcare workers and reduce infection risks. Method: A cross-sectional study was conducted with 295 nursing professionals, including nurses, technicians, and assistants. Data were collected through a questionnaire addressing the reuse of N95 masks, storage between uses, and opinions on the use of the UV-C device for decontamination. Results and Discussion: All participants (n=295) agreed that UV-C decontamination improves biosafety by reducing the handling of potentially contaminated masks. The acceptance of the device was unanimous, confirming its feasibility both in high-demand scenarios, such as the Covid-19 pandemic, and in routine hospital practices. Research Implications: This study demonstrates that implementing UV-C decontamination systems is a practical and effective solution for hospitals, with the potential to increase occupational safety and reduce infectious waste generation. Originality/Value: The study contributes to the literature by highlighting the feasibility and benefits of reusing N95 masks with UV-C decontamination, promoting greater safety in hospital environments.

Experimental application of graphene quantum dots for the removal of nuclear materials from metal and plastic surfaces

This study explores the application of graphene quantum dots (GQDs) as innovative nanomaterials for the efficient removal of nuclear materials from metal and plastic surfaces, especially in contexts involving terrorist threats, such as “dirty bombs” and radiological dispersal devices (RDDs). These devices use conventional explosives combined with radioactive materials to contaminate large areas, posing significant risks to health and the environment. This investigation addresses the growing global concern about the use and threat of such weapons, particularly in the context of escalating wars and the increasing vulnerability of nuclear facilities to security breaches. Our focus is on the unique properties of GQDs—such as their chemical stability, high surface area, quantum confinement effects, and electronic characteristics—that enhance their ability to effectively adsorb radioactive isotopes. We examine the potential of GQDs to interact with various radioactive materials, focusing on isotopes commonly associated with RDDs, such as cesium-137, cobalt-60, strontium-90, and iridium-192. Functionalization techniques are employed to enhance the interaction of GQDs with specific isotopes, thus improving the decontamination process. Our findings reveal that GQDs can efficiently remove iodine-131 (I-131) from several metals: Aluminum (91.27%), zinc (98.67%), and monel (96.40%). They also demonstrate high efficiency in removing I-131 from rigid polyvinyl chloride. On the other hand, GQDs presented moderate efficiency in removing technetium-99m, with removal rates of 64.93% from monel, 55.11% from aluminum, and 41.80% from zinc. Overall, GQDs could play a crucial role in mitigating the consequences of dirty bomb detonations, offering a quick and effective method to reduce radiological impacts in affected areas. This research enhances our understanding of nanomaterials in responding to radiological emergencies, presenting GQDs as a viable solution to contemporary challenges in public health and safety. The implications of this study extend beyond immediate decontamination, suggesting broader applications of GQDs in environmental safety and nuclear safety protocols.

The Contactful Quad: An Effective Tool for Working With Trauma

The purpose of this paper is to explore the potential and development of the drama triangle, the winner’s triangle, and the trauma quadrangle in trauma work and to offer a tool to help identify the roles/patterns replayed when caught in drama. This fosters moving into a more active (winner’s) space and retaining a more integrated position. The authors draw on trauma-informed practices and transactional analysis (TA). They propose that the bystander position in response to trauma can be both an internal and external process. As a tool for working with developmental trauma, the authors offer the contactful quad, which through empowerment and witness aims to support the process of decontamination and deconfusion, to aid the healing process, and to support integration of the unresolved somatic experience of trauma responses. Using clinical vignettes, the authors demonstrate the power of the Actively Courageous position of the contactful quad as an antidote to the Bystander position.

Development of a New Permanganate/Chlorite Process for Water Decontamination.

Development of new technologies with strong selectivity for target pollutants and low sensitivity toward a water matrix remains challenging. Herein, we introduced a novel strategy that used chlorite as an activator for Mn(VII) at pH 4.8, turning the inert reactivity of the pollutants toward Mn(VII) into a strong reactivity. This paved a new way for triggering reactions in water decontamination. By utilizing sulfamethoxazole (SMX) as a typical pollutant, we proposed coupled pathways involving electron transfer across hydrogen bonds (TEHB) and oxidation by reactive manganese species. The results indicated that a hydrogen bonding complex, SMX-ClO2-*, formed through chlorite binding the amino group of SMX initially in the TEHB route; such a complex exhibited a stronger reduction capability toward Mn(VII). Chlorite, in the hydrogen bonding complex SMX-ClO2-*, can then complex with Mn(VII). Consequently, a new reactive center (SMX-ClO2--Mn(VII)*) was formed, initiating the transfer of electrons across hydrogen bonds and the preliminary degradation of SMX. This is followed by the involvement of the generated Mn(V)-ClO2-/Mn(III) in the reduction process of Mn(VII). Such a process showed pH-dependent degradation, with a removal ratio ranging from 80% to near-stagnation as pH increased from 4.8 to 7. Combining with pKa analysis showed that the predominant forms of contaminants were crucial for the removal efficiency of pollutants by the Mn(VII)/chlorite process. The impact of the water matrix was demonstrated to have few adverse or even beneficial effects. With satisfactory performance against numerous contaminants, this study introduced a novel Mn(VII) synergistic strategy, and a new reactivity pattern focused on reducing the reduction potential of the contaminant, as opposed to increasing the oxidation potential of oxidants.

Evaluation of two household decontamination methods on protective mask materials and disinfection effects

Abstract In order to find affective disinfection methods for general public to reuse protective mask, which could address supply shortages in the period of epidemic, household ovens and household ultraviolet disinfection cabinets were used as decontamination tools, and the influence of decontamination process on the protective performance of masks including PFE and TIL, as well as virus (PV I and MHV) inactivation effect were completely evaluated. It was found that the dry heat and UVGI decontamination with household devices had a little impact on PFE or TIL of masks, which indicated that two process had little effect on mask material and face seal fit. The virus inactivation results showed that dry heat decontamination could effectively inactivate the virus on the masks, and UVGI decontamination could not completely inactivate the virus caused by the special shape of masks, which could be concluded that dry heat decontamination with household oven was a feasible method to reuse the mask, and UVGI decontamination was not recommended. This study had guiding significance for the decontamination and reuse of masks by the general public.

Corrosion Resistance Improvement of Mild Steel

Abstract Corrosion’s devastating consequences have become a big issue all over the world. One of the corrosion damage aspects are related to decontamination solutions which are essential for rapid degradation of toxic agents. The decontamination solutions should be non-corrosive to avoid deterioration of steel container. Decontamination solutions comprising have high chlorinating activity so they have a corrosive effect on mild which are used in fabrication of storage tanks. In this case, using inhibitors is one of the most effective strategies to limit the rate of corrosion. This work describes the effect of different compounds; (zinc chromate, cinnamaldehyde, sodium tripolyphosphate, zinc ortho-phosphate, ammonium molybdate and thiourea) on the rate of corrosion of mild steel within dichloroisocyanuric acid decontamination solution. Meanwhile, these inhibitors should not affect active chlorine content which is responsible for the decontamination process. By using kelthoff and AquaChec® methods for measuring active chlorine, it was found that only zinc chromate passed the tests. For measuring electrochemical behaviour of mild steel in decontamination solutions, different techniques were used. Zinc chromate inhibition on mild steel in a 0.5% dichloroisocyanuric acid solution at different temperatures (298–313 K) were studied utilising electrochemical impedance spectroscopy, weight loss, and potentiodynamic polarisation. The results reveal that zinc chromate is an excellent mild steel corrosion inhibitor in dichloroisocyanuric acid, with an inhibition efficacy of 96% at a concentration of 0.005 M. Finally, surface morphology of mild was also investigated using SEM.

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.