Search Results (22)

Titanium (Ti) and its alloys have attracted more interest, as they are widely employed as biomaterials due to their great biocompatibility, excellent strength ratio, and lightweight. However, corrosion occurs slowly due to an electrochemical reaction once the Ti material has been placed in the human body, contributing to infection and failure of implants in medical applications. Thus, the corrosion phenomenon has caused great concern in the biomedical field. It is desirable to make the surface modification to provide better corrosion resistance. The fabrication techniques of the coatings fabricated onto Ti and/or Ti alloy surfaces have been reported, including sol–gel, annealing, plasma spraying, plasma immersion ion implantation, physical vapor deposition, chemical vapor deposition, anodization, and micro-arc oxidation. This review first describes the corrosion types, including localized corrosion (both pitting and crevice corrosion), galvanic corrosion, selective leaching, stress corrosion cracking (SCC), corrosion fatigue (CF), and fretting corrosion. In the second part, the effects of corrosion on the human body were discussed, and the primary cause for clinical failure and allergies has been identified as the excessive release of poisonous and dangerous metal ions (Co, Ni, and Ti) from corroded implants into bodily fluids. The inclusion and exclusion criteria during the selection of literature are described in the third section. In the last section, we emphasized the current research progress of Ti alloy (particularly Ti6Al4V alloy) coatings in biomaterials for medical applications involving dental, orthopedic, and cardiovascular implants for anticorrosive applications. However, there are also several problems to explore and address in future studies, such as the release of excessive metal ions, etc. This review will draw attention to both researchers and clinicians, which could help to increase the coatings fabricated onto Ti and/or Ti alloy surfaces for anticorrosive applications in biomaterials for medical applications. Full article

Activated carbons (ACs) are employed in the nuclear industry to mitigate the emission of potential radioactive iodine species. Their retention performances towards iodine are mainly dependent on the relative humidity due to the competitive effect induced by adsorbed water molecules. Thus, this work will focus on the prediction of AC behavior toward the capture of water vapor to better assess the poisoning effect on radiotoxic iodine removal. For the first time, H₂O breakthrough curves (BTCs) on nuclear grade ACs are predicted through a specific methodology based on the combination of transport phenomena with adsorption kinetics and equilibrium. Three ACs, similar to those deployed in the nuclear context, are considered within the present study. Our model is based on the Linear Driving Force Model (LDF), governed by an intraparticle diffusion mechanism, notably surface and Knudsen diffusions. In addition, the type V isotherms obtained for H₂O and the investigated carbon supports were described through the Klotz equation, taking into account the formation and progressive growth of H₂O clusters within the internal porosity. This methodology allowed us to successfully simulate the H₂O adsorption by a non-impregnated AC, where only physisorption phenomena are involved. In addition, promising results were highlighted when extrapolating to the two other impregnated ACs (AC 5KI and AC Nuclear). Full article

Incidents involving hazardous materials (HAZMAT incidents) can impact human health and the environment. For the development of risk mitigation strategies, it is essential to understand the circumstances of such incidents. A retrospective study (2016–2023) of acute occupational HAZMAT incidents involving multiple patients (>1, including workers, emergency responders and bystanders) reported to the Dutch Poisons Information Center was conducted. We only included incidents that occurred during the performance of work or as a result of a disruption of a work-related process. Patient characteristics, exposure circumstances (such as the substances involved, chemical phase, and type of release (e.g., spill/release or fire/explosion)) and business classes were analyzed to identify risk factors. From 2016 to 2023, the DPIC was consulted about 516 HAZMAT incidents. Inhalation was the most common route of exposure (89%). Patients were often exposed to chemical asphyxiants (n = 156) and acids (n = 151). Most incidents occurred in fixed facilities (n = 447), while 49 incidents occurred during transport. The primary cause was a spill/release (n = 414), followed by a fire/explosion (n = 65). Most patients were exposed to a gas/vapor (n = 421), followed by a liquid (n = 59) or solid (n = 28). Incidents frequently occurred in industry (20%). The majority of patients reported mild to moderate health effects. Surveillance data on HAZMAT incidents are essential for incident preparedness. Poison Center data can help identify risk factors, which can be used to develop risk mitigation strategies to prevent future incidents. Full article

Cu/Ce binary oxides were prepared via the one-pot solvothermal method, and the effects of different cerium precursors (cerium nitrate and cerium ammonium nitrate) on the catalytic activity and resistance to water vapor or CO₂ of the prepared samples for low-temperature CO oxidation reaction were investigated. The physicochemical characteristics of the catalysts were characterized via thermal analyses (TG-DSC), X-ray diffraction (XRD), Raman spectroscopy, N₂ adsorption/desorption, inductively coupled plasma-atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs), and temperature-programmed reduction with H₂ (H₂-TPR). The results indicated that the CuO/CeO₂ catalyst (CC-N) prepared with cerium nitrate showed higher activity for low-temperature CO oxidation, which can be ascribed to its larger specific surface area and pore volume, higher amounts of highly dispersed CuO species with strong interaction with CeO₂, Cu⁺ species, and more active surface oxygen species, compared with the counterpart prepared with cerium ammonium nitrate (CC-NH). Furthermore, the CC-N catalyst also exhibited better resistance to CO₂ poisoning than CC-NH. Full article

Textile chemistry and textile processing laboratories are essential environments for textile product research and development, but they also pose hazards that require rigorous precautions. Among the most common risks is handling chemicals used in the textile industry, such as dyes, solvents, and finishing chemicals, which can be contaminants, corrosive, and flammable, presenting risks of poisoning and fire. Textile processing laboratories also require proper ventilation, as a lack of appropriate ventilation in these environments can accumulate toxic vapors in the air. The most relevant risks and hazards of using textile chemistry laboratories include using equipment such as dyeing autoclaves under pressure and high temperature; drying ovens like furnaces/lab stenters; cylinders of squeezing, calenders, and others, capable of causing severe accidents. These laboratories also generate or handle solid waste and effluents containing, heavy metals to pathogens (e.g., from industrial sludge). It is essential to adopt rigorous safety measures in textile chemistry laboratories, including using personal protective equipment (PPE), proper training of workers, effective ventilation systems, and safe waste disposal protocols. Good laboratory work practices not only reduce risk but also promote better research; more accurate results; and better data. Therefore, this study aimed to map the risks and hazards of textile processing laboratories with a view to accident prevention and formalizing a protocol for good practices. Full article

High-temperature proton exchange membrane fuel cells (HT-PEMFC) directly convert hydrogen and oxygen to produce electric power at a temperature significantly higher than conventional low-temperature fuel cells. This achievement is due to the use of a phosphoric acid-doped polybenzimidazole membrane that can safely operate up to 200 °C. PBI-based HT-PEMFCs suffer severe performance limitations, despite the expectation that a higher operating temperature should positively impact both fuel cell efficiency and power density, e.g., improved ORR electrocatalyst activity or absence of liquid water flooding. These limitations must be overcome to comply with the requirements in mobility and stationary applications. In this work a systematic analysis of an HT-PEMFC is performed by means of electrochemical impedance spectroscopy (EIS), aiming to individuate the contributions of components, isolate physical phenomena, and understand the role of the operating conditions. The EIS analysis indicates that increases in both the charge transfer and mass transport impedances in the spectrum are negatively impacted by air humidification and consistently introduce a loss in performance. These findings suggest that water vapor reduces phosphoric acid density, which in turn leads to liquid flooding of the catalyst layers and increases the poisoning of the electrocatalyst by phosphoric acid anions, thus hindering performance. Full article

Recently a hand-held, carbon-nanotube-based electronic nose became available on the market. Such an electronic nose could be interesting for applications in the food industry, health monitoring, environmental monitoring, and security services. However, not much is known about the performance of such an electronic nose. In a series of measurements, the instrument was exposed to low ppm vapor concentrations of four volatile organic compounds with different scent profiles and polarities. Detection limits, linearity of response, repeatability, reproducibility, and scent patterns were determined. The results indicate detection limits in the range of 0.1–0.5 ppm and a linear signal response in the range of 0.5–8.0 ppm. The repeatability of the scent patterns at compound concentrations of 2 ppm allowed the identification of the tested volatiles based on their scent pattern. However, the reproducibility was not sufficient, since different scent profiles were produced on different measurement days. In addition, it was noted that the response of the instrument diminished over time (over several months) possibly by sensor poisoning. The latter two aspects limit the use of the current instrument and make future improvements necessary. Full article

Different transition metals (Cr/Fe/Mn/Co) derived catalysts supported on γ-Al₂O₃ were prepared by the isovolumetric impregnation method for catalytic ozonation of acetone (C₃H₆O), and their catalytic activities under industrial complex conditions were investigated. Among them, CrO_x/γ-Al₂O₃ catalyst with Cr loading of 1.5%, abbreviated as Cr1.5%, achieved the best activity, benefitting from its larger surface area, larger proportion of Cr⁶⁺/Cr, more chemically desorbed oxygen species O_β, appropriate acidity, and superiority of low-temperature reducibility. Simulated industrial conditions were used to investigate the applicability of Cr1.5% catalysts for catalytic ozonation of acetone. Results illustrated that the optimum temperature range was 120–140 °C, with molar ratio O₃/C₃H₆O > 6. Different C₃H₆O initial concentrations had less effect over the activity of Cr1.5% catalysts, with little residual ozone, confirming the applicability of Cr1.5% catalysts in industrial application. The effects of sulfur/water vapor on catalytic activity were also investigated, and satisfactory resistance to sulfur or water vapor individually was obtained. Finally, in-situ DRIFTS measurement was carried out, to explore and illustrate mechanisms of acetone catalytic ozonation pathways and sulfur/water poisoning. Full article

Chemical warfare agents (CWA) can poison people through the skin and cause injury, and the use of chemical protective clothing (CPC) is an important way to protect personnel from injury. CPC performance strongly depends on chemical protective materials, and satisfactory protective materials must meet various requirements, including protective performance, physiological comfort, mechanical performance, and cost effectiveness. Here, low-cost materials were used to prepare PVDF sodium sulfonate composite membranes with different contents of modified graphene oxide (GO-SSS). Their tensile properties, contact angle, permeability, and selectivity were tested and analyzed. The results show that when the addition ratio of GO-SSS to the bare membrane is 0.5%, the composite membrane has desirable permeation selectivity of water vapor/CWA simulant vapor and desirable mechanical properties. Hence, our sodium sulfonate composite membrane of PVDF with GO-SSS is an ideal material for potential applications in CPC. Full article

The present research was undertaken to study the antifungal activities of Origanum onites L. and Ziziphora clinopodioides L. essential oils against three different isolates (M1-5, M2-1 and M3-5) of Botrytis cinerea (in vitro tests) and to investigate the vapor contact impacts on fungus and strawberry fruit quality (in vivo tests). Antifungal activities of these oils were tested by following the poisoned food technique at four different concentrations (0.25, 0.50, 1.00 and 2.00 mL/L) against B. cinerea. In vitro studies suggested that the 0.50 mL/L and 1.00 mL/L doses of O. onites and 1.00 mL/L and 2.00 mL/L doses of Z. clinopodioides provide high mycelial growth inhibition, 85.29–94.12% and 39.12–94.12%, respectively, by direct addition to food. Thus, these doses were tested in in vivo conditions, as a vapor contact treatment against two isolates (M1-5 and M3-5) of B. cinerea inoculated on strawberry cv. Camarosa fruits. Results showed that both O. onites and Z. clinopodioides essential oils have a moderate to high impact on the prevention of gray mold. The oils were also found to have a slight to moderate impact on weight loss and the loss of soluble solids concentration. Overall, the results demonstrated that the tested oils are a potential biodegradable alternative to fungicides. Full article

Process safety helps prevent the unexpected and unplanned release of flammable and toxic chemicals, leading to poisonous gas clouds, fires, and explosions. Vapor cloud explosions (VCEs) are among the most severe hazards to humans and the environment in process facilities. Therefore, process safety demands to use best and reliable techniques to model VCEs in process industries and storage tanks of flammable chemicals. In this regard, the Computational Fluid Dynamics (CFD) models are more appropriate, as these models provide three-dimensional (3D) modeling of all sequences of events in an accident. In this study, CFD is used to model VCE in two industrial accidents: the Amuay refinery disaster (happened in 2012) and the Indian Oil Corporation’s (IOC) Jaipur terminal (2009). This work studies 3D CFD modeling of flammable cloud explosion in the real-time configuration for both accidents. FLACS (FLame ACceleration Simulator), a CFD software, is used to simulate the loss of hydrocarbon containment, cloud formation, and explosion in both industrial case studies. The ignition locations and grid sizes were varied to analyze their influence on explosion overpressure, temperature, vapor velocity, and fuel mass. This work also investigated the effect of geometry complexity on the explosion. Results showed that, as opposed to the coarse grid, the fine grid provides more precision in the analysis. The study also reveals an explosion overpressure of the order 4–15 bar (g) for the given case studies. This study’s results can help perform a qualitative and quantitative risk assessment of the Amuay refinery accident and Jaipur fire. The simulation of different scenarios can help develop and improve safety guidelines to mitigate similar accidents. Full article

Biofuels are receiving increased scientific attention, and recently different biofuels have been proposed for spark ignition engines. This paper presents the state of art of using biofuels in spark ignition engines (SIE). Different biofuels, mainly ethanol, methanol, i-butanol-n-butanol, and acetone, are blended together in single dual issues and evaluated as renewables for SIE. The biofuels were compared with each other as well as with the fossil fuel in SIE. Future biofuels for SIE are highlighted. A proposed method to reduce automobile emissions and reformulate the emissions into new fuels is presented and discussed. The benefits and weaknesses of using biofuels in SIE are summarized. The study established that ethanol has several benefits as a biofuel for SIE; it enhanced engine performance and decreased pollutant emissions significantly; however, ethanol showed some drawbacks, which cause problems in cold starting conditions and, additionally, the engine may suffer from a vapor lock situation. Methanol also showed improvements in engine emissions/performance similarly to ethanol, but it is poisonous biofuel and it has some sort of incompatibility with engine materials/systems; its being miscible with water is another disadvantage. The lowest engine performance was displayed by n-butanol and i-butanol biofuels, and they also showed the greatest amount of unburned hydrocarbons (UHC) and CO emissions, but the lowest greenhouse effect. Ethanol and methanol introduced the highest engine performance, but they also showed the greatest CO₂ emissions. Acetone introduced a moderate engine performance and the best/lowest CO and UHC emissions. Single biofuel blends are also compared with dual ones, and the results showed the benefits of the dual ones. The study concluded that the next generation of biofuels is expected to be dual blended biofuels. Different dual biofuel blends are also compared with each other, and the results showed that the ethanol–methanol (EM) biofuel is superior in comparison with n-butanol–i-butanol (niB) and i-butanol–ethanol (iBE). Full article

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts. Full article

Through Density Functional Theory (DFT), we have unveiled the atomic structures, adsorption characteristics and electronic structures of the poisonous and explosive vapor, m-dinitrobenzene (m-DNB), on pure, defective and various doped AlN nanosheets from a physical perspective. It is found that the adsorption energy, band gap change and sensitivity to the vapor are significantly increased through atomic-scale modification of the nanosheet. The AlN monolayer with Al-N divacancy has the largest adsorption energy and has potential to be utilized as adsorption or filtration materials for m-DNB vapor. The Si-doped AlN nanosheet possesses a much larger band gap change (−0.691 eV) than the pure nanosheet (−0.092 eV) after adsorption and has a moderate adsorption energy, which could be candidate material for explosive vapor sensing. This theoretical work is proposed to provide guidance and clue for experimentalists to develop more effective two-dimensional materials for environmental safety and sustainability. Full article

Doubly promoted MeMo/Nb₂O₅ catalysts, in which Me = Pt, Ni, or Co oxides were prepared for the selective catalytic reduction of NO_x by CO reaction (CO-SCR). Comparable chemical, textural, and structural analyses revealed similarities between NiMo and CoMo impregnated on Nb₂O₅, in contrast to PtMo sites, which were not homogeneously dispersed on the support surface. Both the acid function and metal dispersion gave a synergistic effect for CO-SCR at moderate temperatures. The reactivity of PtMo catalysts towards NO_x and CO chemisorption was at low reaction temperatures, whereas the NO_x conversion over CoMo was greatly improved at relatively high temperatures. Careful XPS, NH₃-TPD, and HRTEM analyses confirmed that the large amounts of strong and moderate acid sites from PtO_x entrapped on MoO₃ sites induced high NO_x conversions. NiMo/Nb₂O₅ showed poor performance in all conditions. Poisoning of the MeMo sites with water vapor or SO₂ (or both) provoked the decline of the NO_x conversions over NiMo and PtMo sites, whereas the structure of CoMo ones remained very active with a maximum NO_x conversion of 70% at 350 °C for 24 h of reaction. This was due to the interaction of the Co³⁺/Co²⁺ and Mo⁶⁺ actives sites and the weak strength Lewis acid Nb⁵⁺ ones, as well. Full article