Disinfection Applications Research Articles

Thermo-responsive/anti-biofouling chitosan hydrogel beads in situ decorated with silver nanoparticles for water disinfection.

The development of a sustainable and eco-friendly silver-based hybrid nanocomposite for safe and efficient point-of-use (POU) water disinfection remains a challenge. Herein, a simple and facile approach was proposed for the in situ immobilization of silver nanoparticles (AgNPs) on chitosan-g-poly (sulfobetaine methacrylate) (CS-g-PSBMA) hydrogel beads, which have been achieved via graft copolymerization of sulfobetaine methacrylate along the chitosan chains followed by a drop method. The AgNPs-decorated CS-g-PSBMA hydrogel beads were characterized and their bactericidal efficacy towards Escherichia coli was evaluated concurrently with their anti-biofouling behaviors. The results indicated that the grafted PSBMA hydrogels on CS would not only enhance the immobilization of more AgNPs (122.63 mg/g material), but also restricted the silver release (only 0.015 % after the 14th day of incubation), which surpassed numerous other AgNPs-based nanocomposites for water disinfection. Moreover, the release of silver can be modulated by altering the temperature due to the thermosensitivity of PSBMA, and the maximum concentration of silver leaching in the effluent was 33.1-52.3 μg/L at 25-60 °C. Importantly, the synthesized AgNPs-based CS-g-PSBMA can exert both exceptional bactericidal and superior anti-biofouling capabilities as well as reusability features, indicating sustained antibacterial effectiveness and significant potential for practical applications in water disinfection.

P-266. Does routine use of sporicidal disinfectants for all post-discharge hospital rooms reduce environmental contamination with Clostridioides difficile spores?

Abstract Background Asymptomatic carriage of Clostridioides difficile is common in healthcare facilities. Routine use of sporicidal disinfectants for all post-discharge rooms has been proposed as a measure to address environmental shedding by carriers, but limited information is available on the effectiveness of this approach. Recovery of C. difficile from CDI and non-CDI rooms in hospitals using sporicidal disinfectants only in CDI rooms versus in all post-discharge rooms Methods We conducted a culture survey to assess environmental contamination with C. difficile in patient rooms after cleaning and disinfection in 30 acute care hospitals, including 17 (57%) using sporicidal disinfectants (11 peracetic acid-based products and 6 chlorine-based products) for all post-discharge rooms and 13 (43%) using sporicidal disinfectants (1 peracetic acid-based product and 12 chlorine-based products) only for C. difficile infection (CDI) rooms. Cultures for C. difficile were collected from 10 rooms per hospital (up to 3 CDI rooms), including high-touch surfaces in the room (N=10 sites) and in the bathroom (N=10 sites). A mixed-effects logistic regression model was used to compare contamination in non-CDI (primary outcome) and CDI rooms in facilities using sporicidal disinfectants in non-CDI and CDI rooms versus only in CDI rooms. Results Of 595 total patient rooms and bathrooms cultured, 339 (57%) were in hospitals using sporicidal disinfectants for all post-discharge rooms and 256 (43%) were in hospitals using sporicidal disinfectants only in CDI rooms. As shown in Figure 1, there was a trend toward reduced C. difficile contamination in non-CDI and CDI rooms in facilities using sporicidal disinfectants in all post-discharge rooms versus only in CDI rooms, but the difference was not statistically significant (P>0.62). Conclusion In a survey of 30 hospitals, use of sporicidal disinfectants for all post-discharge rooms was not associated with a statistically significant reduction in C. difficile contamination in non-CDI rooms. Additional studies are needed to determine if interventions to improve the effectiveness of sporicidal disinfectant application will reduce C. difficile contamination in real-world settings. Disclosures Curtis Donskey, MD, Clorox: Grant/Research Support|Pfizer: Grant/Research Support

Evaluating Potential Plant-based Root Canal Irrigants for their Anti-bacterial Effectualness: A Lab-based Research Study

Abstract Introduction: The escalating resistance of bacterial strains to conventional antimicrobial agents necessitates the exploration of alternative natural remedies. This study investigates the anti-bacterial efficacy of Triphala and Aloe Vera extracts, individually and in varying proportions, against Enterococcus fecalis compared to established chemical agents, specifically 0.5% and 3% sodium hypochlorite (NaOCl). Materials and Methods: Standard strains of E. Coli were inoculated in the Mueller–Hinton agar plates incubated at 37°C for 24 h, using the agar well diffusion method with irrigants categorised as Group I: Triphala extract, Group II: Aloe vera extract, Group III: Triphala and aloe vera extract in 1:2 combination, Group IV: NaOCl in 0.5% concentration and Group V: NaOCl in 3% concentration. Data were analysed using ANOVA and post hoc tests, with significance set at P < 0.05. Results: The results demonstrated significant anti-bacterial activity of both natural products, with varying effects based on their combination ratios. Combination therapies using Triphala and Aloe Vera produced enhanced anti-bacterial effects compared to individual applications against E. fecalis bacterial strains. The results were not statistically significant, indicating herbal irrigants performed equivalently as compared to both the concentrations of NaOCl used in this research study. Conclusion: Combinations of natural products in this study exhibit significant anti-bacterial activity, suggesting their potential role in further applications for disinfection and endodontic treatments which needs to be corroborated with further clinical studies.

π-Stacked organic heterojunction enabled efficient hydrogen peroxide photoproduction.

Hydrogen peroxide (H2O2) finds wide application in disinfection, chemical production, and bleaching owing to its sustainability and ease of storage compared to hydrogen. However, the current industrial engineering practices for producing photocatalysts used in H2O2 generation face challenges such as low yields with organic catalysts and high costs associated with inorganic catalysts. In light of these challenges, we investigate a viable method utilizing a simple condensation reflux technique to synthesize pure organic heterojunction photocatalysts featuring a π-π stacked structure derived from graphitized carbon nitride (melem) and meso-tetrakis (4-carboxyphenyl) porphyrin, enabling efficient H2O2 production without the necessity of sacrificial agents. The synthesized catalyst demonstrates an impressive H2O2 production rate of 106mmol/h.g.L under seawater conditions and 77.67mmol/h.g.L under pure water conditions in ambient air. Coupling to a solar evaporator, an H2O2 concentration reaches 0.88wt%. Transient absorption spectroscopy revealed ultrafast charge separation which enabled efficient photocatalysis.

Effect of double disinfectant application during premilking teat disinfection on teat cleanliness, bacterial count, and mastitis in pasture-grazed dairy cows

Effect of double disinfectant application during premilking teat disinfection on teat cleanliness, bacterial count, and mastitis in pasture-grazed dairy cows

Bandgap-Tunable Aluminum Gallium Oxide Deep-UV Photodetector Prepared by RF Sputter and Thermal Interdiffusion Alloying Method

Gallium oxide (Ga2O3) has gained considerable attention due to its wide bandgap, the availability of native substrates, and its excellent properties for solar-blind photodetectors, transparent electronics, and next-generation power devices. However, the expensive Ga2O3 native substrates have restricted its widespread adoption. To reduce costs and further the development of β-Ga2O3-based devices, there is a need for bandgap-tunable oxide films with high crystal quality for deep-ultraviolet (DUV) photodetectors and high-breakdown-field power devices. This study introduces a Thermal Interdiffusion Alloying method to address these requirements. It focuses on developing deep ultraviolet (DUV) photodetectors using β-Ga2O3 thin films on sapphire substrates by promoting the diffusion of aluminum (Al) atoms from the substrate into the film, resulting in the formation of aluminum gallium oxide (β-(AlxGa1−x)2O3). The aluminum content is controlled by adjusting the process temperature, allowing for tunable detection wavelengths and enhanced DUV sensing capabilities. Radio frequency (RF) sputtering optimizes the film’s quality by adjusting the sputtering power and the argon/oxygen (Ar/O2) flow ratio. Material analysis indicates that this method expands the optical bandgap and shifts the response wavelength to 210 nm, significantly boosting the performance of the fabricated photodetectors. This research presents considerable potential for advancing DUV photodetectors across various disinfection applications.

Residual level of chlorine disinfectant, the formation of disinfection by-products, and its impact on soil enzyme activity.

Disinfectants can kill pathogenic microorganisms, effectively block the spread of infectious diseases, and are widely used during epidemics. However, a little has been studied about the environmental hazards caused by the heavy use of disinfectants. In this paper, the residual situation of chlorine ions in the soil, possible disinfection by-products (DBPs), and effects on soil enzyme activities after using 84 disinfectants (main component: sodium hypochlorite) and hypochlorite disinfectant (main component: hypochlorous acid) were investigated. It was found that the residual rates were generally higher than 92% for the 84 disinfectant treatment and between 80% ~ 90% for the hypochlorite disinfectant treatments. The overall change in chlorine ion concentration in the soil-leaching solution of the hypochlorite disinfectant treatments was relatively small and stable compared to the 84 disinfectant treatments. Several types of trihalomethanes (THMs) were detected after 24h of disinfection. The generation concentration of THMs was higher for the 84 disinfectant than for the hypochlorite disinfectant. The generation of trichloromethane was the highest, ranging from 1000 to 3000μg/L. Soil enzyme activities changed much when the soil was treated with the disinfectant for 28days. The above results indicated that hypochlorite disinfectant was safer and more stable than 84 disinfectants, and trichloromethane should be strictly controlled as a key indicator among the disinfection by-products. In addition, the long-term application of disinfectants affects soil enzyme activities obviously.

Enhancing power density in D-mode GaN HEMT direct-current triboelectric nanogenerators through ICP-etched surface engineering

In the evolving landscape of energy harvesting, the refinement of friction properties in metal-semiconductor direct current triboelectric nanogenerators (MSDC TENGs) has garnered significant attention. While prior research predominantly concentrated on achieving superior performance in MSDC TENGs through material manipulation, structural adjustments, and friction mode optimization, there has been a noticeable dearth of investigations into surface engineering or modification of semiconductor materials. In this paper, the surface patterning of depletion mode GaN-based high electron mobility transistor (D-GaN HEMT) as friction materials is done by inductively coupled plasma etching method, involving both mechanism analysis and experimental exploration. Through modulation of etching depth and pattern density, a systematically arranged diamond pattern is created on the surface, augmenting surface roughness and charge density. Consequently, the surface-patterned D-GaN HEMT TENG achieves a maximum short-circuit current of 60 µA and a peak power density of 4.05 W/m², which is about 2.8 times greater than the pristine D-GaN HEMT TENG. Furthermore, the power supply capabilities of the surface-patterned D-GaN HEMT TENG are scrutinized, revealing its proficiency in capacitive charging and discharging. The successful activation of a deep ultraviolet LED underscores its potential applications in ultraviolet disinfection. This research holds substantial significance in optimizing the power generation efficiency and performance of MSDC TENGs employing D-GaN HEMT.

Insights into the Acute Stress of Glutaraldehyde Disinfectant on Short-Term Wet Anaerobic Digestion System of Pig Manure: Dose Response, Performance Variation, and Microbial Community Structure

The outbreak of epidemics such as African swine fever has intensified the use of disinfectants in pig farms, resulting in an increasing residual concentration of disinfectants in environmental media; however, the high-frequency excessive use of disinfectants that damage pig farm manure anaerobic fermentation systems and their mechanisms has not attracted enough attention. Especially, the complex effects of residual disinfectants on anaerobic fermentation systems for pig manure remain poorly understood, thus impeding the application of disinfectants in practical anaerobic fermentation systems. Herein, we explored the effects of glutaraldehyde disinfectant on methane production, effluent physicochemical indices, and microbial communities in a fully automated methanogenic potential test system (AMPTSII). The results show that adding glutaraldehyde led to remarkable alterations in methane production, chemical oxygen demand (COD), volatile solids (VS), and polysaccharide and phosphorus concentrations. During the anaerobic process, the production of methane displayed a notable decrease of 5.0–98% in all glutaraldehyde treatments, and the trend was especially apparent for treatments containing high levels of glutaraldehyde. Comparisons of the effluent quality showed that in the presence of 0.002–0.04% glutaraldehyde, the COD and total phosphorus (TP) increased by 12–310% and 15–27%, respectively. Moreover, the addition of 0.01–0.08% glutaraldehyde decreased the ammonium (NH4+-N) concentration and VS degradation rate by 7.7–15% and 4.9–26.2%. Furthermore, microbiological analysis showed that the glutaraldehyde treatments had adverse effects on the microbial community. Notably, certain functional bacteria were restrained, as highlighted by the decreases in relative abundance and microbial diversity by 1.3–17% and 0.06–21%, respectively. This study provides a theoretical basis for the rational use of disinfectants in anaerobic fermentation systems.

Novel NaNbO3-based, ferroelectric ceramics with excellent polarization and electric potential for antibacterial applications

Low surface electric potential (<1V) limits the large-scale commercial application of ferroelectric antibacterial ceramics. We propose a strategy based on charge-balancing doping to enhance polarization and potential in NaNbO3(NN)-based ceramics for disinfection application. The Mg2+ modified NN showed a superior bactericidal effect greater than 80 % for 1.5 h and 99.8 % for 3 h without heating or ultrasonication, which is superior to other published works. This is mainly due to its excellent surface electric potential of 1.72 V and defect-related discharge current of 141.9 pA compared to NN and Ca2+ modified NN. Ferroelectric properties demonstrated that NN-Mg possesses a lower EC of ∼40 kV/cm and a higher Pr of ∼32 μC/cm2. Furthermore, the combination of XRD, Raman shift, PFM, and permittivity testing suggests that the smaller domain and enhanced ferroelectric properties in NN-Mg originated from amphoteric doping. Finally, simulation results of the electric field distribution indicated that NN-Mg had a stronger attraction or repulsion to bacteria with negatively charged surfaces.

Evaluation of the Efficacy of Disinfectants in Reducing Contamination of Bacterial and Viral Murine Pathogens on Gloved Hands.

Disinfectant application to gloved hands before handling SPF mice is standard practice to minimize transmission of pathogens and microbial contamination between cages. The risk of contamination with murine pathogens on gloves as well as the efficacy of disinfectant application for this step is largely unknown. This study aimed to determine if murine norovirus (MNV), Helicobacter spp., and Rodentibacter spp. are detectable on gloved hands and, if they are, to evaluate how effective the application of a hydrogen peroxide-based disinfectant (Rescue) or 70% ethanol is in reducing the transfer of these pathogens while handling multiple cages of mice. Mice with natural infections of these pathogens were handled without the application of any disinfectant and the gloves were swabbed for PCR testing. All pathogens were detected via PCR with Helicobacter spp. the most frequently transferred in 83% of the cages handled. The mice were then divided into 4 treatment groups based on the product applied to gloves before handling: Rescue, 70% ethanol, sterile water, and no product. Mice in each cage were briefly handled, and the gloves were swabbed with ATP swabs after each cage and swabs for PCR testing after handling 4 and 9 cages, consecutively. All pathogens were detected via PCR in all treatment groups, and neither Rescue nor 70% ethanol was superior to water or no product in reducing contamination. Rescue and 70% ethanol were effective in maintaining lower levels of organic microbial contamination than water and no product for consecutive handling of up to 3 and 4 cages of mice, respectively. This study indicates that exposure to MNV, Helicobacter spp., and Rodentibacter spp. from handling mice is a risk and the application of Rescue or 70% ethanol is not completely effective in eliminating transfer of these pathogens.

Study on the effect of chlorogenic acid on the antimicrobial effect, physical properties and model accuracy of alginate impression materials.

Dental impressions are essential for accurately capturing the detailed anatomy of teeth and surrounding oral structures. However, these impressions often become contaminated with saliva and blood, making proper disinfection necessary. The application of chemical disinfectants has been associated with negative side effects, leading to suboptimal disinfection practices in clinical settings. The purpose of this study was to evaluate the effectiveness of chlorogenic acid (CA) as a disinfectant for alginate impression materials, the impact of CA disinfection on the physical properties and dimensional accuracy of alginate impressions was also investigated. The physical properties of alginate impression materials, such as elastic recovery, strain-in-compression, initial setting time, and fluidity, were assessed after mixing the alginate impression materials with three different concentrations of CA solution (10 mg/mL, 15 mg/mL, 20 mg/mL). To evaluate the antimicrobial effect of CA, alginate impressions mixed with a 10 mg/mL CA solution and impressions mixed with distilled water (control group) were contaminated with four types of microorganism: Escherichia coli, Staphylococcus aureus, Candida albicans, and Streptococcus pneumoniae. Following a five-minute incubation period, a CA solution at a concentration of either 50mg/mL, 55 mg/mL, or 60 mg/mL was sprayed on the samples for disinfection. Samples were collected at different time intervals (10 min, 20 min, 30min) and cultured to determine the number of colony-forming units (CFU/mL), providing insight into the antimicrobial efficacy of these CA solutions. The dimensional accuracy of alginate impressions was assessed in three groups: one with alginate impressions mixed with distilled water, another with alginate impressions sterilized with available chlorine (2,000 mg/L) mixed with distilled water, and the last group consisting of alginate impressions mixed with 10 mg/mL CA solution and sprayed with 60 mg/mL CA solution. Both the standard model and the plaster model underwent 3D scanning, and the data were processed and compared by software. The root mean square (RMS) was used as a parameter to evaluate the deviation between models. All alginate impression materials mixed with either 10 mg/mL, 15 mg/mL, or 20 mg/mL concentrations of CA solution met the ISO 21563 standard for elastic recovery, strain-in-compression, and fluidity. However, only the material mixed with a concentration of 10 mg/mL CA had an initial setting time within the range specified by the T-6505 Japanese industrial standard. The application of CA solution by mixing or spraying showed significant antimicrobial effects on Staphylococcus aureus, Escherichia coli, Candida albicans, and Streptococcus pneumoniae. There was no significant difference in the dimensional accuracy of the alginate impressions between the group of the CA solution applied, the blank group, or the chlorine intervention group.

Photochemical Action of Far‐UVC Radiation (222 nm) in Wastewater Treatment and Indoor Air Disinfection

AbstractUltraviolet‐ C irradiation can effectively disinfect various pathogens present in air, surfaces, and water. Various recent research studies suggest use of KrCl* (krypton‐chloride) excimer lamps to disinfect high‐risk public spaces having pathogenic bateria and viruses, as they emit Far‐UVC radiation (222 nm) with lower health risks than germicidal UVC (254 nm). The purification of water and air having pollutants and pathogens is a critical challenge in environmental protection and public health assurance. Far‐UVC excimer lamps (222 nm) have shown potential in decontaminating various organic pollutants, however, their efficacy against inorganic pollutants present in wastewater and indoor air as well as associated chemistry requires further investigations for wider acceptance. This review examines various photochemical action of Far‐UVC radiation (222 nm) in wastewater treatment and indoor air disinfection, elaborating their potential for inorganic pollutant removal in wastewater as well as challenges associated with their application in disinfection of indoor air.

Study of the viruсidal properties of the disinfectant "DezV Ultra"

The first and most important link in the system of preventing the occurrence and spread of avian influenza and Newcastle disease is monitoring and effective prevention. At the same time, an important stage in the system of veterinary and sanitary measures is the disinfection of poultry facilities. Many disinfectants containing various classes of chemical compounds as active substances have been developed and proposed for practical use. Large-scale production and practical application of disinfectants is not possible without preliminary laboratory evaluation of their antimicrobial properties, determination of the spectrum of biocidal activity, and physicochemical and toxicological properties. Our work aimed to study the virucidal properties of the new aldehyde disinfectant "DezV Ultra" on test models of highly pathogenic avian influenza and Newcastle disease viruses. The specified works were carried out in the Department of Poultry Diseases Research and Molecular Diagnostics of the National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine" following the methodological recommendations "Methods for determination and evaluation of safety and quality indicators of disinfectants, detergents, and disinfection agents used during production, storage, transport, and sale of products of animal origin" (2010). Based on the results of the research, it was determined that the effective action of the preparation "DezV Ultra" in neutralizing the above-mentioned viruses on metal, tile, and wood surfaces begins at the final concentration of 0.5%

Heterogeneous survival upon disinfection underlies evolution of increased tolerance.

Disinfection is key to control the spread of infections. But the application of disinfectants bears the risk to promote the evolution of reduced susceptibility to antimicrobials if bacteria survive the treatment. The ability of individual bacteria to survive disinfection can display considerable heterogeneity within isogenic populations and may be facilitated by tolerant persister subpopulations. Using time-kill kinetics and interpreting the data within a mathematical framework, we quantify heterogeneity and persistence in Escherichia coli when exposed to six different disinfectants. We find that the level of persistence, and with this the risk for disinfection failure, depends on the disinfectant. Importantly, evolution experiments under recurrent disinfection provide evidence that links the presence of persisters to the ability to evolve reduced susceptibility to disinfectants. This study emphasizes the impact of heterogeneity within bacterial populations on disinfection outcomes and the potential consequences for the evolution of antimicrobial resistances.

Tripartite synergy: Photodegradation of congo red and bromothymol blue with concurrent bacterial photoinhibition using ZnCe/Bi2Mn2O6/rGO nanocomposites

The present research studies show the multidimensional characteristics of ZnCe/Bi2Mn2O6/rGO nanostructures for photocatalytic degradation of bromothymol blue (BTB), Congo red (CR) and photoinhibition of E. coli and S. aureus. A new solvothermal protocol was applied for the synthesis of ZnCe/Bi2Mn2O6/rGO nanomaterial. Important analytical techniques were applied for the characterization of the said nanomaterials. When allowed to visible light, the said nanostructure demonstrated excellent photocatalytic degradation of both the said dyes. The findings revealed that almost 99 % of both dyes were eliminated in just 30 min. In the absence of light, there was less than 60 % decline in both dyes even after 100 min. The ZnCe/Bi2Mn2O6/rGO was tested multiple times against the said dyes, and after seven cycles, its efficiency was reduced by only 15 %. Moreover, the nanostructures exhibited promising antibacterial properties by inducing photoinhibition of both E. coli and S. aureus bacteria. The inhibition zones of ZnCe/Bi2Mn2O6/rGO under visible light irradiation were measured to be approximately 17 ± 0.2 mm against E. coli and 19 ± 0.3 mm against S. aureus. These nanostructures effectively impeded bacterial growth and viability, underscoring their potential for applications in water disinfection and as antibacterial coatings. They are promising options for a variety of applications, especially as catalysts in many industries, due to their non-toxic nature and thermal stability. This work presents fascinating avenues for further investigation into the application of nanocomposites in healthcare and environmental preservation.

A Computation-Guided Design of Highly Defined and Dense Bimetallic Active Sites on a Two-Dimensional Conductive Metal-Organic Framework for Efficient H2O2 Electrosynthesis.

Electrochemical synthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e--ORR) provides an alternative method to the energy-intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e--ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e--ORR-inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first-principle predictions, a substrate-free and two-dimensional conductive metal-organic framework (Ni-TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi-site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni-TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high-density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni-TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e--ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (>90 %/85 % H2O2 selectivity within 0-0.8 V vs. RHE and >18.2/18.0 mol g-1 h-1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high-density active sites, promoting high-efficiency electrosynthesis of H2O2 and beyond.

A Computation‐Guided Design of Highly Defined and Dense Bimetallic Active Sites on a Two‐Dimensional Conductive Metal–Organic Framework for Efficient H2O2 Electrosynthesis

AbstractElectrochemical synthesis of hydrogen peroxide (H2O2) via the two‐electron oxygen reduction reaction (2e−‐ORR) provides an alternative method to the energy‐intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e−‐ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e−‐ORR‐inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first‐principle predictions, a substrate‐free and two‐dimensional conductive metal–organic framework (Ni‐TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi‐site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni‐TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high‐density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni‐TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e−‐ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (&gt;90 %/85 % H2O2 selectivity within 0–0.8 V vs. RHE and &gt;18.2/18.0 mol g−1 h−1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high‐density active sites, promoting high‐efficiency electrosynthesis of H2O2 and beyond.

Global transcriptional analysis for molecular responses of Alicyclobacillus acidoterrestris spores in drinking water after low- and medium-pressure ultraviolet irradiation

Ultraviolet (UV) irradiation can effectively disinfect water contaminated with pathogens. However, the biological mechanisms of inactivation by different types of UV irradiation are unknown. The present study investigated the inactivation mechanisms of Alicyclobacillus acidoterrestris spores in water by low-pressure UV (LPUV) and medium-pressure UV (MPUV) using a quasi-collimated beam apparatus. Global transcriptomic data obtained by RNA-seq revealed 291 shared differentially expressed genes (DEGs) that damaged DNA, reduced biofilm formation, and had other reactions. The individual downregulated DEGs (n = 123) mainly related to cell motility, membrane transport, and metabolism were induced by LPUV, and in turn contributed to energy-saving and metabolic activity inhibition, forcing bacteria into a viable but non-culturable (VBNC) state. The individual upregulated DEGs (n = 244) following MPUV treatment were mainly enriched in cell motility, membrane transport, metabolism, DNA replication and repair, and spore germination pathways. This results in high-energy consumption, severe damage to genetic material, and enhanced spore germination accelerated cell death. Additionally, hub genes in the protein-protein interaction network were mainly involved in transcription and translation. These findings contribute to the comprehensive understanding of the inactivation mechanisms of different types of UV irradiation, and will improve applications of UV disinfection in the treatment of water.

Priority areas for the use of solar water disinfection (SODIS) in Brazil: a spatial approach

ABSTRACT This paper presents a methodology for the development of a potential and priority use map for the application of the solar water disinfection (SODIS) method in Brazil. The assessment of solar radiation was conducted, with a particular focus on the annual average global horizontal irradiance (GHI). The water vulnerability index (WVI) and the economic-social-ecosystemic (ESE)-WVI were developed and employed as indicators to define the priority regions for the application of SODIS. The combination of the GHI and WVI maps yielded a SODIS usage potential index (SUPI). The combination of the SUPI map with information pertaining to the human, economic, and ecosystem dimensions of water vulnerability (ESE-WVI) yielded the SODIS usage priority index. The analysis revealed that the country exhibits favorable levels of solar radiation, making the implementation of SODIS a viable option, particularly in the Northeast region. Furthermore, the study identified regions with greater water vulnerability, such as the semi-arid region and some parts of the Amazon, as priorities for the application of SODIS. In conclusion, SODIS represents a viable water treatment technique for various regions in Brazil, particularly those with abundant solar radiation and concerns regarding water security.