Environmental Decontamination Research Articles

Horizontal versus vertical strategies for infection prevention: current practices and controversies.

Healthcare-associated infections (HAIs) represent a major burden on healthcare facilities. Effective infection prevention strategies are essential to prevent the spread of HAIs. These can be broadly classified as vertical and horizontal interventions. Through this review, we aim to assess the merits of these strategies. Vertical strategies include active surveillance testing and isolation for patients infected or colonized with a particular organism. These strategies are beneficial to curb the spread of emerging pathogens and during outbreaks. However, the routine use of contact precautions for organisms such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus remains controversial. Horizontal interventions are larger-scale and reduce HAIs by targeting a common mode of transmission shared by multiple organisms. Among these, hand hygiene, chlorhexidine gluconate bathing of select patients and environmental decontamination are the most high-yield and must be incorporated into infection prevention programs. As antimicrobial stewardship is also an effective horizontal strategy, antimicrobial stewardship programs must operate in synergy with infection prevention programs for maximal impact. Overall, horizontal interventions are considered more cost-effective and have a broader impact. Infection control programs may opt for a combination of vertical and horizontal strategies based on local epidemiology and available resources.

Trace Pt-loading transition metal hydroxides as efficient catalyst for vaporized hydrogen peroxide decomposition

Vaporized hydrogen peroxide (VHP) holds great promise for the decontamination of space environment. Nevertheless, following the decontamination process, highly concentrated VHP within confined spaces is harmful to the human body. Hence, trace Pt-loading (0.57 wt%) transition metal hydroxides nanosheets anchored on Ni foam (Pt@NiAlCrFe-LDHs/NF) were prepared for VHP decomposition. Importantly, a strong electronic interaction between NiAlCrFe layer double hydroxides (NiAlCrFe-LDHs) and Pt was evidenced by XPS. Meanwhile, unique nanosheet-like morphology and rich mesoporous structure endow the catalyst with excellent performance. The catalytic activity of Pt@NiAlCrFe-LDHs/NF is approximately twice that of NiAlCrFe-LDHs/NF and seven times that of Pt/NF. The improved catalytic efficiency of Pt@NiAlCrFe-LDHs/NF results from the reduction in energy barrier for VHP decomposition reaction caused by the introduction of trace Pt. After ten recycling experiments, this catalyst still shows good durability with no significant deterioration in VHP decomposition efficiency. Finally, the growth mechanism of Pt@NiAlCrFe-LDHs/NF was also proposed and discussed.

New Insights into Materials for Pesticide and Other Agricultural Pollutant Remediation.

The increase in the world population and the intensification of agricultural practices have resulted in the release of several contaminants into the environment, especially pesticides and heavy metals. This article reviews recent advances in using adsorbent and catalytic materials for environmental decontamination. Different materials, including clays, carbonaceous, metallic, polymeric, and hybrid materials, are evaluated for their effectiveness in pollutant removal. Adsorption is an effective technique due to its low cost, operational simplicity, and possibility of adsorbent regeneration. Catalytic processes, especially those using metallic nanoparticles, offer high efficiency in degrading complex pesticides. Combining these technologies can enhance the efficiency of remediation processes, promoting a more sustainable and practical approach to mitigate the impacts of pesticides and other agricultural pollutants on the environment. Therefore, this review article aims to present several types of materials used as adsorbents and catalysts for decontaminating ecosystems affected by agricultural pollutants. It discusses recent works in literature and future perspectives on using these materials in environmental remediation. Additionally, it explores the possibilities of using green chemistry principles in producing sustainable materials and using agro-industrial waste as precursors of new materials to remove contaminants from the environment.

Novel 2D layered g-C3N4 nanocomposite materials for sustainable wastewater treatment by catalytic degradation of toxic dye

The photocatalytic degradation technique is one of the suitable ways of dealing with environmental pollutant decontamination. This study demonstrates the ability of graphitic carbon nitride (g-C3N4) nanocomposites containing tellurium (Te) and molybdenum disulfide (MoS2) to photocatalytically destroy organic cationic methylene blue (MB) dye, which is primarily used in the textile industry. Using the alkali treatment approach, layered graphitic carbon nitride (g-C3N4) was created. Using MoS2 and Te, several g-C3N4 nanocomposites were created using ultrasonic calcination techniques. After the MoS2 and Te were immobilized individually, the composites underwent a methodical characterization process utilizing a variety of instruments, including XRD and SEM. Using a 2D layered nano-g-C3N4 substrate, the photo-catalytic degradation reaction of MB was observed, and a UV spectrophotometer was used to determine the absorbance of the MB dye. Using 0.2 % MoS2/g-C3N4 and 5 % Te/g-C3N4, the photocatalytic degradation efficiency of the MB dye (10, 15, and 20 mg/L) solution was examined. In comparison to other produced nanocomposites, the 5 % Te/g-C3N4 composite was shown to have the highest photocatalytic activity in terms of dye degradation ability, and about 100 % of the MB dyes were degraded in less than 60 minutes. As the concentration of MB increased, the dye degradation efficiency of g-C3N4 nanocomposites steadily dropped, and the degradation rate of MB was around 1.5 mg/L.

Magnetic adsorbents from co‐pyrolysis of non‐woody biomass and red mud for water decontamination

AbstractRed mud (RM) and non‐woody biomass are both underutilized resources for renewable composite materials, which could be used in environmental decontamination processes. This study aims to investigate the efficacy of co‐pyrolyzing non‐woody biomass with RM to produce a magnetic biochar composite. When pyrolyzed, RM is reduced to magnetic iron while the non‐woody biochar is responsible for the adsorption of organic compounds. Ibuprofen, acetaminophen, methyl orange, and methylene blue were used as test compounds to investigate the overall adsorptive capacity of the composite and to determine the possible adsorption mechanisms of biochar produced from RM pyrolyzed with switch grass, phragmites, rice husk, and miscanthus. The composite produced from a 1 to 1 mixture of RM and miscanthus showed the highest adsorption capacity with 13.8 and 8.34 mg/g of ibuprofen and acetaminophen adsorbed, respectively, which is attributed to its greater ‐interactions as a result of lower surface oxygen sites. Different ratios of RM to biomass were also tested for the production of the miscanthus composite, where it was found that the 1:2 ratio showed the best overall adsorption with 25.9 mg/g removal of acetaminophen, surpassing the miscanthus biochar's at 17.9 mg/g.

Enzyme-Immobilized Porous Crystals for Environmental Applications.

Developing efficient technologies to eliminate or degrade contaminants is paramount for environmental protection. Biocatalytic decontamination offers distinct advantages in terms of selectivity and efficiency; however, it still remains challenging when applied in complex environmental matrices. The main challenge originates from the instability and difficult-to-separate attributes of fragile enzymes, which also results in issues of compromised activity, poor reusability, low cost-effectiveness, etc. One viable solution to harness biocatalysis in complex environments is known as enzyme immobilization, where a flexible enzyme is tightly fixed in a solid carrier. In the case where a reticular crystal is utilized as the support, it is feasible to engineer next-generation biohybrid catalysts functional in complicated environmental media. This can be interpreted by three aspects: (1) the highly crystalline skeleton can shield the immobilized enzyme against external stressors. (2) The porous network ensures the high accessibility of the interior enzyme for catalytic decontamination. And (3) the adjustable and unambiguous structure of the reticular framework favors in-depth understanding of the interfacial interaction between the framework and enzyme, which can in turn guide us in designing highly active biocomposites. This Review aims to introduce this emerging biocatalysis technology for environmental decontamination involving pollutant degradation and greenhouse gas (carbon dioxide) conversion, with emphasis on the enzyme immobilization protocols and diverse catalysis principles including single enzyme catalysis, catalysis involving enzyme cascades, and photoenzyme-coupled catalysis. Additionally, the remaining challenges and forward-looking directions in this field are discussed. We believe that this Review may offer a useful biocatalytic technology to contribute to environmental decontamination in a green and sustainable manner and will inspire more researchers at the intersection of the environment science, biochemistry, and materials science communities to co-solve environmental problems.

Heavy metals removal from industrial wastewater of Biskra (Algeria) by Arundo donax and Phragmites australis.

Industrial effluents pose a serious environmental problem, because they contain toxic contaminants mainly heavy metals that are the most dangerous to humans, animals, plants, and the environment in general. Phytoremediation using macrophytes is an adopted technique for the environment decontamination due to its efficiency and cost-effectiveness. The present study aims to highlight the capabilities of macrophytes to remove heavy metals from wastewater of Biskra region (Algeria). The methodology consists of filling out the filters planted with Arundo donax and Phragmites australis with raw industrial wastewater, then recovering decontaminated water after 15 days to assess removal of lead, copper, zinc, and iron. Both plants had shown a good efficiency for the removal of metals loaded in wastewater eliminating about 94 to 98% of initial concentration. In addition, calculated bioaccumulation factor (BAF) had confirmed the accumulation of heavy metals in different parts of experimental plants; recorded values of BAF > 1 allowed the consideration of Arundo donax and Phragmites australis as good hyper-accumulator plants. Obtained results confirm the efficiency of phytoremediation technology using macrophytes for the wastewater treatment in particular and the environment decontamination in general.

Z-scheme WO3/AgI heterojunction grown on flexible carbon fibers for efficient organic degradation and bacterial inactivation

Z-scheme WO3/AgI heterojunctions on carbon fiber (CF) cloth were fabricated through in-situ hydrothermal method and chemical bath deposition route. The CF@WO3/AgI cloth achieved highly efficient photocatalytic abilities under visible light, which could eliminate 95.7 % of Rhodamine B (RhB) in 70 min and 70.0 % of tetracycline hydrochloride (TC-HCl) in 110 min, superior to those of CF, CF@WO3 and CF@AgI cloths. Moreover, the catalyst was able to achieve 7.0 ± 0.16 log10 CFU/mL reduction of E. coli cells within 40 min. Recycling test confirmed the repeatability and stability of CF@WO3/AgI cloth. The enhanced photocatalytic performance was attributed to the increased visible light utilization, accelerated charge carriers separation and high photo-redox capabilities which came from the formation of Z-scheme heterojunction. This work provided inspiration for the construction of high-efficiency flexible photocatalysts for environmental decontamination.

Melanin for Photoprotection and Hair Coloration in the Emerging Era of Nanocosmetics.

Nanotechnology is revolutionizing fields of high social and economic impact. such as human health preservation, energy conversion and storage, environmental decontamination, and art restoration. However, the possible global-scale application of nanomaterials is raising increasing concerns, mostly related to the possible toxicity of materials at the nanoscale. The possibility of using nanomaterials in cosmetics, and hence in products aimed to be applied directly to the human body, even just externally, is strongly debated. Preoccupation arises especially from the consideration that nanomaterials are mostly of synthetic origin, and hence are often seen as "artificial" and their effects as unpredictable. Melanin, in this framework, is a unique material since in nature it plays important roles that specific cosmetics are aimed to cover, such as photoprotection and hair and skin coloration. Moreover, melanin is mostly present in nature in the form of nanoparticles, as is clearly observable in the ink of some animals, like cuttlefish. Moreover, artificial melanin nanoparticles share the same high biocompatibility of the natural ones and the same unique chemical and photochemical properties. Melanin is hence a natural nanocosmetic agent, but its actual application in cosmetics is still under development, also because of regulatory issues. Here, we critically discuss the most recent examples of the application of natural and biomimetic melanin to cosmetics and highlight the requirements and future steps that would improve melanin-based cosmetics in the view of future applications in the everyday market.

Assessing the stability and sporicidal efficacy of oxidizing disinfectants

The role of the healthcare environment in the transmission of clinical pathogens is well established. EN 17126:2018 was developed to address the need for regulated sporicidal product testing and includes a realistic medical soil to enable validation of products that claim combined cleaning and disinfection efficacy. To investigate the chemical stability and sporicidal efficacy of oxidizing disinfectant products in the presence of simulated clean and medical dirty conditions. Disinfectant stability and sporicidal efficacy were evaluated in like-for-like ratios of soil:product. Disinfectants were exposed to simulated test soils and free chlorine, chlorine dioxide or peracetic acid concentrations were measured using standard colorimetric methods. Efficacy of disinfectants against C. difficile R027 endospores was assessed as per EN 17126:2018. Comparisons of performance between clean and medical dirty conditions were performed using one-way analysis of variance. Correlation analysis was performed using Pearson product-moment correlation. Performance of chlorine-releasing agents (sodium dichloroisocyanurate, chlorine dioxide and hypochlorous acid) was concentration dependent, with 1000 ppm chlorine showing reduced stability and efficacy in dirty conditions. By contrast, peracetic acid product demonstrated stability and consistently achieved efficacy in dirty conditions. These results have implications for clinical practice, as ineffective environmental decontamination may increase the risk of transmission of pathogens that can cause healthcare-associated infections.

Identifying Contact Time Required for Secondary Transmission of Clostridioides difficile Infections by Using Real-Time Locating System.

Considering patient room shortages and prevalence of other communicable diseases, reassessing the isolation of patients with Clostridioides difficile infection (CDI) is imperative. We conducted a retrospective study to investigate the secondary CDI transmission rate in a hospital in South Korea, where patients with CDI were not isolated. Using data from a real-time locating system and electronic medical records, we investigated patients who had both direct and indirect contact with CDI index patients. The primary outcome was secondary CDI transmission, identified by whole-genome sequencing. Among 909 direct and 2,711 indirect contact cases, 2 instances of secondary transmission were observed (2 [0.05%] of 3,620 cases), 1 transmission via direct contact and 1 via environmental sources. A low level of direct contact (113 minutes) was required for secondary CDI transmission. Our findings support the adoption of exhaustive standard preventive measures, including environmental decontamination, rather than contact isolation of CDI patients in nonoutbreak settings.

Copper-Based Two-Dimensional Metal-Organic Frameworks for Fenton-like Photocatalytic Degradation of Methylene Blue under UV and Sunlight Irradiation.

To efficiently degrade organic pollutants, photocatalysts must be effective under both ultraviolet (UV) radiation and sunlight. We synthesized a series of new metal-organic frameworks by using mild hydrothermal conditions. These frameworks incorporate three distinct bipyridyl ligands: pyrazine (pyr), 4,4'-bipyridine (bpy), and 1,2-bis(4-pyridyl)ethane (bpe). The resulting compounds are denoted as [Cu(pyz)(H2O)2MF6], [Cu(bpy)2(H2O)2]·MF6, and [Cu(bpe)2(H2O)2]·MF6·H2O [M = Zr (1, 3, and 5) and Hf (2, 4, and 6)]. All six compounds exhibited a two-dimensional crystal structure comprising infinitely nonintersecting linear chains. Compound 3 achieved 100% degradation of methylene blue (MB) after 8 min under UV irradiation and 100 min under natural sunlight in the presence of H2O2 as the electron acceptor. For compound 5, 100% MB degradation was achieved after 120 min under sunlight and 10 min under UV light. Moreover, reactive radical tests revealed that the dominant species involved in photocatalytic degradation are hydroxyl (•OH), superoxide radicals (•O2-), and photogenerated holes (h+). The photodegradation process followed pseudo-first-order kinetics, with photodegradation rate constants of 0.362 min-1 (0.039 min-1) for 3 and 0.316 min-1 (0.033 min-1) for 5 under UV (sunlight) irradiation. The developed photocatalysts with excellent activity and good recyclability are promising green catalysts for degrading organic pollutants during environmental decontamination.

Efficient photocatalytic reduction of Cr(VI) and degradation of tetracycline by Bi2Se3@ZnIn2S4 binary heterostructures enriched with sulfur vacancies: Mechanism and mineralization analysis

Constructing a sulfur-vacancy-enriched heterostructure offers advantages in enhancing photocatalytic performance due to the synergy between the vacancy’s electron-trapping and the internal electric field (IEF) features. In this study, a series of IEF-modulated type-I heterostructures containing sulfur vacancies-rich ZnIn2S4 (SV-ZIS) and Bi2Se3 (BSe) was rationally developed by hydrothermal and reduction methods. The optimized BSe@SV-ZIS catalyst shows an outstanding photocatalytic Cr(VI) reduction and tetracycline degradation rates, which are ∼ 2.1 and ∼ 1.5 times higher than that of pure SV-ZIS and BSe, respectively. Notably, the enhanced catalytic performance of binary samples could be linked to efficient absorption of the full spectrum of light, heterojunction formation and larger contact area to enhance the charge carriers movement at their interface and exceptional photo-stability. By assisting DRS, VB-XPS, and UPS analyses, details of the energy band position, charge carriers transport route, and preliminary photocatalytic mechanism were systematically explored. Furthermore, radical scavenging and electron paramagnetic resonance experiments were conducted to provide evidence of the participation of the reactive species during photocatalysis over BSe@SV-ZIS. Kinetic analysis revealed that the rate of photocatalytic process adheres to the Langmuir–Hinshelwood kinetic model. These results demonstrated that the heterostructuring approach holds significant potential as an effective avenue for developing photocatalysts that can harness both visible and NIR light, offering promising solutions to contemporary challenges in the realms of environmental decontamination and energy.

Tuning interfacial oxygen vacancy level of bismuth oxybromide to enhance photocatalytic degradation of bisphenol A

Oxygen vacancies (OVs) have garnered significant interest for their role as active sites, enhancing the catalytic efficiency of various catalysts. Despite their widespread application in environmental purification processes, the generation of OVs conventionally depends on high-temperature conditions and strong reducing agents for the extraction of surface partial oxygen atoms from catalysts. In this work, bismuth oxybromide (BiOBr) nanosheets with varying levels of OVs were synthesized via a simple and effective solvothermal method. This novel method affords precise control over the conduction band (CB) and valence band (VB) positions of BiOBr. The presence of different OVs exhibited varying photocatalytic efficiencies in the degradation of bisphenol A (BPA) under visible light irradiation, with higher levels of OVs resulting in superior photocatalytic performance. Furthermore, radical scavenger experiments demonstrated that superoxide oxides (O2•−) and holes (h+) were the primary reactive oxygen species for BPA degradation. Additionally, BiOBr-OVs exhibited excellent anti-interference and stability in water matrices containing diverse inorganic anions and organic compounds. This work provides a simple and effective approach for the fine-regulating of catalysts through interfacial defect engineering, paving the way for their practical application in environmental decontamination.

Imidazolium-Functionalized Conjugated Polymer for On-Site Visual and Ultrasensitive Detection of Toxic Hexavalent Chromium.

Hexavalent chromium [Cr(VI)] is considered a serious environmental pollutant that possesses a hazardous effect on humans even at low concentrations. Thus, the development of a bifunctional material for ultratrace-selective detection and effective elimination of Cr(VI) from the environment remains highly desirable and scarcely reported. In this work, we explore an imidazolium-appended polyfluorene derivative PF-DBT-Im as a highly sensitive/selective optical probe and a smart adsorbent for Cr(VI) ions with an ultralow detection limit of 1.77 nM and removal efficiency up to 93.7%. In an aqueous medium, PF-DBT-Im displays obvious transformation in its emission color from blue to magenta on exclusively introducing Cr(VI), facilitating naked-eye colorimetric detection. Consequently, a portable sensory device integrated with a smartphone is fabricated for realizing real-time and on-site visual detection of Cr(VI). Besides, the imidazolium groups attached onto side chains of PF-DBT-Im are found to be highly beneficial for achieving selective and efficient elimination of Cr(VI) with capacity as high as 128.71 mg g-1. More interestingly, PF-DBT-Im could be easily regenerated following treatment with KBr and can be recycled at least five times in a row. The main factor behind ultrasensitive response and excellent removal efficiency is found to be anion-exchange-induced formation of a unique ground-state complex between PF-DBT-Im and Cr(VI), as evident by FT-IR, XPS, and simulation studies. Thus, taking advantage of the excellent signal amplification property and rich ion-exchange sites, a dual-functional-conjugated polymer PF-DBT-Im is presented for the concurrent recognition and elimination of Cr(VI) ions proficiently and promptly with great prospects in environmental monitoring and water decontamination.

Electrochemical investigation of phosphorous and boron heteroatoms incorporated reduced graphene oxide electrode material for supercapacitor applications

Graphene-based nanomaterials are becoming common components for consumer products due to their outstanding charge carrier ability, high surface area, high thermal stability, and great potential for environmental decontamination. Nowadays, heteroatoms added carbon allotropes are providing better electrochemical performances in the field of supercapacitors as an electrode material. In this present work, boron and phosphorus heteroatoms were introduced in the network of reduced graphene oxide to increase the capacitance of the supercapacitor. The B and P incorporated rGO (PB-rGO) electrode material was prepared by the hydrothermal method. The properties of the electrode material were analyzed using structural, morphological, and elemental analysis. The prepared electrode material was used as a working electrode material in supercapacitors. In 1 M H2SO4 aqueous electrolyte medium, a maximum specific capacitance of 436 F g−1 was found for PB-rGO in a three-electrode configuration. In a symmetric configuration, a power density of 394 W kg−1 and an energy density of 12.48 Wh kg−1 were observed for the PB-rGO electrode. The cyclic stability analysis showed 97.6 % retention after 10,000 cycles at the current density of 3 A g−1.

Development of Fe0 biochar composites synergistically activated with MgFe2O4 and Fe2+ through one-step pyrolyzing Fe sludge and MgCl2 for enhanced aqueous Cr(VI) removal

The surface passivation layer on Fe0 severely restricts its reactivity during environmental decontamination. In this study, a new composite—an Fe0 biochar composite (Fe0/BC) coupled with MgFe2O4 and Fe2+—was first developed for enhanced Cr(VI) removal by simple co-pyrolysis of Fe sludge (FS) with MgCl2. The characterization results demonstrated that MgFe2O4 and Fe0 could be formed simultaneously at 700 ℃. However, MgFe2O4 disappeared at temperatures of 800 and 900 ℃. By varying the flow rate of N2 and holding time, Fe0/BC was further optimized based on the determined MgCl2 to FS mass ratio (1.9:10.0) and temperature (700 °C). The optimal Fe0/BC (MBC700120-400–30) achieved a Cr(VI) removal efficiency of 97.67%, which was 2.43 times higher than that of the unmodified Fe0/BC obtained at 700 ℃. This enhanced reactivity was directly related to the electron transfer of Fe0 stimulated by MgFe2O4 as well as the conversion of passive corrosion products into Fe3O4 facilitated by soluble Fe2+ components. The predicted maximum adsorption capacity of MBC700120-400–30 was 85.43 mg/g (pH = 5) and the removal of Cr(VI) was dominated by chemisorption. The reduction of Cr(VI) to Cr(Ⅲ) was identified as the principal removal mechanism. Overall, this study demonstrates a novel strategy for developing functional Fe0-based materials for water contamination treatment.

Mitigation Due To Contamination Of Sarin Chemical Weapons To Reduce The Nubika Disaster

The misuse of chemical weapons can have highly dangerous consequences for both humans and the surrounding environment. One of the deadliest chemical weapons is sarin, which can lead to death within minutes of exposure. To reduce the consequences of a chemical weapons disaster, effective contamination mitigation is required. This research employs a qualitative descriptive method, with a literature review study, to discuss contamination mitigation strategies that can be used to minimize the consequences of a chemical weapons disaster caused by the use of sarin. Some of these strategies include the use of protective clothing, gas masks, and environmental decontamination. In emergency situations, protective clothing and gas masks can help shield individuals from exposure to chemical weapons. Furthermore, timely environmental decontamination can aid in reducing contamination levels and the risk of exposure. In addition to contamination mitigation strategies, preventive efforts are also crucial in lessening the impact of a chemical weapons disaster involving sarin. Prevention efforts involve chemical weapon surveillance, training and education, as well as the development of better detection and protection technologies. By implementing the appropriate contamination mitigation strategies and effective prevention efforts, it is hoped that the consequences of a chemical weapons disaster involving sarin can be significantly reduced.

Cr and N co-doped biochar driving controllable peroxydisulfate activation pathways to degrade tetracycline: Pyrrolic N inducing singlet oxygen generation

Efficiently inducing nonradical pathway in peroxydisulfate (PDS) activation is promising in environmental decontamination due to the oxidation selectivity and anti-interference ability, but still remains challenges, e.g., low efficiency and high cost. In this study, a series of Cr and N co-doped biochar (Cr-N/BC) was synthesized via pyrolysis by using melamine-retanned chrome shaving (MCS) as precursors, to activate PDS toward the tetracycline (TC) degradation. The introduction of pyrrolic N on Cr-N/BC not only boosted the catalyst reactivity, but also altered the complexation state of PDS, thus triggering a shift in oxidative modes from the radical pathway into a singlet oxygen (1O2) dominated nonradical pathway, in which, the relative contribution of the nonradical oxidation to the TC degradation increased from 0 to 98%. Structure-activity relationship determination unveiled that pyrrolic N on Cr-N/BC surface greatly changed the charge distribution and chemical property of biochar, thereby facilitating the decomposition of PDS and generation of 1O2. In addition, ecotoxicological safety of the intermediates of TC in the 1O2-dominated pathway was evaluated to validate the superiority of the nonradical process. This study advances our understanding of designing reaction-oriented nonradical carbon-catalysis for selective decontamination.

Assessing CaDPA levels, metabolic activity, and spore detection through deuterium labeling.

Many strains among spore-forming bacteria species are associated with food spoilage, foodborne disease, and hospital-acquired infections. Understanding the impact of environmental conditions and decontamination techniques on the metabolic activity, viability, and biomarkers of these spores is crucial for combatting them. To distinguish and track spores and to understand metabolic mechanisms, spores must be labeled. Staining or genetic modification are current methods for this, however, these methods can be time-consuming, and affect the viability and function of spore samples. In this work, we investigate the use of heavy water for permanent isotope labeling of spores and Raman spectroscopy for tracking sporulation/germination mechanisms. We also discuss the potential of this method in observing decontamination. We find that steady-state deuterium levels in the spore are achieved after only ∼48 h of incubation with 30% D2O-infused broth and sporulation, generating Raman peaks at cell silent region of 2200 and 2300 cm-1. These deuterium levels then decrease rapidly upon spore germination in non-deuterated media. We further find that unlike live spores, spores inactivated using various methods do not lose these Raman peaks upon incubation in growth media, suggesting these peaks may be used to indicate the viability of a spore sample. We further observe several Raman peaks exclusive to deuterated DPA, a spore-specific chemical biomarker, at e.g. 988 and 2300 cm-1, which can be used to track underlying changes in spores involving DPA. In conclusion, permanent spore labeling using deuterium offers a robust and non-invasive way of labeling bacterial spores for marking, viability determination, and characterising spore activity.