Water Sterilization Research Articles

The Effect of Water Quality on the Performance Growth of Vannamei Shrimp (Litopenaeus vannamei) at the Center for Brackish Aquaculture Fisheries

Vaname shrimp is one of the leading commodities of the aquaculture sector, with high production rates influenced by the rapid growth period and relatively short maintenance time, high stocking density production system, has a high appetite for food and has good resistance to disease. This study aims to assess the effect of water quality on the growth of vaname shrimp (Litopenaeus vannamei) in ponds. Water quality measured includes temperature, salinity, dissolved oxygen (DO), and pH, all of which play an important role in the growth and health of shrimp. The methods used in this study included periodic measurements of water quality parameters in the morning and evening in four ponds (A5.1, A5.2, A6.1, and A6.2), as well as observations of Average Body Weight (ABW), Average Daily Growth (ADG), and Survival Rate (SR) of shrimp. The results showed that ponds A5.1, A5.2, and A6.1 showed an increase in SR and biomass values, while A6.2 experienced a decrease in SR and biomass values caused by the outbreak of White Feces Disease. This is influenced by temperature, salinity, and DO parameters that are not in the optimal range for shrimp growth. Fluctuations in water quality parameters can significantly affect shrimp metabolism and health. Therefore, good water quality management, including water change cycles and sterilisation, is essential to prevent health problems and improve the growth of vaname shrimp. This study emphasises the need for attention to water quality in vaname shrimp farming to achieve optimal results.

Low‐cost 0D and 2D carbon material co‐decorated titanium dioxide ternary heterojunction for rapid and efficient bacteria killing under visible light

AbstractRecently, the issue of bacterial resistance has gotten worse because of the overuse of antibiotics. The newborn superbacteria, such as vancomycin‐resistant bacteria, were hard to kill, inspiring researchers to find new ways to kill the bacteria efficiently. TiO2 was used as an efficient photocatalyst for water splitting and pollutant degradation. However, the weak efficiency limited the application to solve the drug‐resistance problem. Consequently, the incorporation of low‐cost 0D carbon quantum dots (CQDs) and 2D graphene oxide (GO) was pursued to amplify the visible light absorption capabilities of TiO2 and thereby elevate its photocatalytic activity. After forming the heterogeneous interface of CQDs and TiO2, CQDs converted part of visible light into wavelength less than 400 nm using the up‐conversion property. The modification of CQDs enabled electrons to be easily transferred from the conduction band of CQDs to the conduction band of TiO2. Meanwhile, GO can act as an electron acceptor, reduce the recombination efficiency of holes and electrons, and transfer the photogenerated electrons in the redox reaction in the heterogeneous interface. Because of the excellent absorption of GO, TiO2/CQDs/GO reached 57.8°C after 20 min irradiation under 1.5 times sunlight, which provided a prerequisite for photodynamic antibacterial therapy/photothermal antibacterial therapy synergistic antibacterial potential. TiO2/CQDs/GO possessed an antibacterial efficiency as high as 99.3% toward Staphylococcus aureus which has a bright future in disinfection in vivo and medical devices as well as water sterilization.

Simple sterilization of rural household water by LDH (Layered Double Hydroxide)-embedded sheet

Abstract The lack of access to safe water is an urgent problem in rural communities. LDH (layered double hydroxide) is a potent material that effectively adsorbs most pathogens through its positive charge, but its powdery nature restricts its use in batch water. To overcome this, we developed LDH-embedded non-woven fabric sheets (LDH-ES) as a practical solution for sterilizing batch water. Zn/Al-LDH and Mg/Al-LDH were synthesized and embedded in fabric. Using Escherichia coli (DH5 α), two variants of 100 mL of DH5 α inoculated test solutions (1200 CFU/mL) were prepared: nutritionally poor (test water A) and moderately nutritious (test water B). Without adding LDH-ES, the viable counts in test water A were almost unchanged until 24 h, whereas in test water B it increased up to 19,000-fold after 24 h. Upon adding 162 cm2 of Zn/Al-LDH-ES (LDH = 0.2 g), both test water reduced the viable count to 0 CFU/mL after 3 h, achieving complete sterilization. In contrast, with Mg/Al-LDH-ES, the viable count after 24 h was 0 CFU/mL for test water A and 530 CFU/mL for test water B. The superior performance of Zn/Al-LDH-ES is ascribed to the additional antimicrobial effect of zinc. LDH-ES, easily retrievable post-sterilization, proves suitable for disinfecting rural household water.

Development of a Portable Residual Chlorine Detection Device with a Combination of Microfluidic Chips and LS-BP Algorithm to Achieve Accurate Detection of Residual Chlorine in Water.

Chlorine is widely used for sterilization and disinfection of water, but the presence of excess residual chlorine in water poses a substantial threat to human health. At present, there is no portable device which can achieve accurate, rapid, low-cost, and convenient detection of residual chlorine in water. Therefore, it is necessary to develop a device that can perform accurate, rapid, low-cost, and convenient detection of residual chlorine in water. In this study, a portable residual chlorine detection device was developed. A microfluidic chip was studied to achieve efficient mixing of two-phase flow. This microfluidic chip was used for rapid mixing of reagents in the portable residual chlorine detection device, reducing the consumption of reagents, detection time, and device volume. A deep learning algorithm was proposed for predicting residual chlorine concentration in water, achieving precise detection. Firstly, the microfluidic chip structure for detecting mixed reagents was optimized, and the microfluidic chip was fabricated by a 3D-printing method. Secondly, a deep learning (LS-BP) algorithm was constructed and proposed for predicting residual chlorine concentration in water, which can realize dual-channel signal reading. Thirdly, the corresponding portable residual chlorine detection device was developed, and the detection device was compared with residual chlorine detection devices and methods in other studies. The comparison results indicate that the portable residual chlorine detection device has high detection accuracy, fast detection speed, low cost, and good convenience. The excellent performance of the portable residual chlorine detection device makes it suitable for detecting residual chlorine in drinking water, swimming pool water, aquaculture and other fields.

PCN-222/H3PW12O40/graphene oxide@cotton cloth with improved photocatalytic/photothermal properties for water decontamination

In this study, a novel visible-light-driven PCN-222/H3PW12O40/graphene oxide@cotton cloth (PCN-222/HPW/GO@Cot) photocatalytic platform was developed for efficient water sterilization and purification. PCN-222/HPW/GO ternary photocatalyst was prepared via one-pot solvothermal method, and anchored onto cotton cloth though catechol-amine reaction. By introducing HPW as the quasi-semiconductor co-catalyst and efficient electron trap, the photocatalytic activity of PCN-222 was boosted. Besides, the addition of GO further enhanced electron transfer capability and photothermal properties. PCN-222/HPW/GO@Cot exhibited significantly improved organic dye photodegradation and sterilization efficiencies compared to PCN-222 and PCN-222/HPW coated cotton cloths. It also maintained consistent organic dye removal efficiency over reuse cycles and retained high sterilization activity after repeated washings, indicating its remarkable durability and coating stability. The band positions and the enhanced photocatalytic/photothermal mechanisms were investigated in depth. This research suggests the great potential of PCN-222/HPW/GO@Cot photocatalytic platform for practical water purification and sterilization applications, and the potential to become multifunctional textiles.

Sustainable water sterilization by nano-ZnO using anisotropic polysaccharide columns derived from agro-waste stalk

The escalating demand for clean water and proliferation of microbial contamination in water have challenged ecosystems and human health safety. ZnO NPs are widely used as environmental restoration agents, but their efficacy in water decontamination is hindered by low biological toxicity. In order to enhance its sterilization efficiency, we propose a top-down strategy utilizing the unique maze structure of corn stalk pith (CSP) as a germ trapper for ZnO. The in-situ delignified CSP offers abundant active sites for the adsorption of Zn2+, exhibiting the typical behaviors of monolayer, physisorption, endothermicity, spontaneity, and randomness. This adsorption behavior exerts an influence on microscopic morphology of the composite column, consequently resulting in alterations to antibacterial properties. The results show that the hybrid column fabricated under the Zn2+ initial dosage of 1.00 mol/L at 30 h for 40 °C, possesses such optimal features as stacked grain-shaped ZnO NPs of 669.3 mg/g loading amount with adhesion coefficients of 0.73 ∼ 0.86 for bacterial microparticles. Consequently, the assembled bio-filter can eliminate E. coli and S. aureus as high as 99.7 % and 96.5 % respectively, attributed to CSPP labyrinth structure to enhance pathogen capture from water and facilitate ZnO-mediated inactivation. The collective findings emphasize the viability of agro-waste stalks as bio-filters for water purification.

Design of a Device Based on an LED Matrix for Water Sterilization

The scarcity of potable water emphasizes the urgent need to develop and implement more sustainable treatment technologies, considering both energy consumption and environmental impact. These technologies require effective disinfection systems that avoid the use of chemicals. Innovations in this area, utilizing UV-LED technology, can significantly improve efficiency, reduce costs, and mitigate environmental impacts. This study aimed to evaluate the antimicrobial properties of various encapsulated UV light-emitting diodes (LEDs) to identify the most suitable candidate for constructing an LED array capable of disinfecting large volumes of water. Different devices from various manufacturers, with differing costs and wavelengths, were examined, leading to the selection of the optimal candidate (LED 2) based on its antimicrobial effectiveness and cost-effectiveness. The impact of parameters such as bacterial concentration, sample volume, exposure time, and conditions on disinfection capacity was thoroughly investigated. Exposure to LED 2 resulted in substantial reductions in the viability of bacteria and yeast, demonstrating efficacy even against Clostridium perfringens endospores. Subsequently, an LED array was developed based on these findings and rigorously evaluated for efficacy, confirming its effectiveness as an efficient and environmentally friendly water treatment device.

Amino acid-mediated chiral Ag@Au with circularly polarized light induced photothermal and photodynamic synergistic photocatalytic disinfection

As the deterioration of the environment, microbiological contamination of drinking water is threatening human health. Therefore, it is crucial to investigate rapid, reliable, and safe sterilization techniques. In this study, chiral Ag@Au nanoparticles (L/D-NPs) were synthesized using an amino acid-mediated protocol. The L/D-NPs demonstrated outstanding photothermal and photodynamic capabilities when irradiated with linearly polarized (LP) light. The photothermal and photodynamic synergism demonstrated by L/D-NPs resulted in high sterilization capability against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). It was noteworthy that these results were chirality-independent. With the interaction of chirality-matched circularly polarized light (CPL) and chiral NPs, excellent sterilization performance could be achieved even at a much lower concentration. The mechanisms were investigated using Finite-Difference Time-Domain (FDTD) simulations and photocurrent-time measurements. In addition, under identical conditions, chiral NPs were found to maintain excellent sterilization performance for the complex microbial system of actual river water. This work offers novel guidance and insights into photocatalytic disinfection, including sterilization of water and public facilities.

Simultaneous water sterilization and photodegradation of malachite green based on Z-scheme heterojunction of bimetallic sulfide and zinc phthalocyanine

Multifunctional Z-scheme heterojunction has emerged as an alternative to achieve the photocatalytic sterilization and photodegradation of organic pollutants. Herein, a novel Z-scheme heterojunction based on bimetallic sulfide and zinc phthalocyanine (ZnPc) was established as a robust bifunctional photocatalyst to sterilize and degrade malachite green (MG) contained in wastewater. Ultrathin Ag2S/MoS2 nanosheets were vertically grown over ZnPc nanorods in situ through hydrothermal method, generating a Z-scheme heterojunction (denoted as Ag2S/MoS2@ZnPc). Results showed enhanced photo-adsorption within full spectrum range, narrowed band gap, and modulated electron structure of metal sites of the heterojunction were achieved via the synergistic effect of interface and defect engineering. The Z-scheme Ag2S/MoS2@ZnPc heterojunction demonstrated a boost in the production of reactive oxygen species, superior photothermal effect, high self-supplying H2O2 ability (737.72 μmol g−1h−1), and the controllable release behavior of Ag+ ions under near-infrared (NIR) light irradiation. Almost 100 % bacteria in wastewater were eliminated by this Z-scheme heterojunction owing to the multimodal antibacterial mechanism under NIR illumination (808 nm, 1.0 W cm−2). Moreover, the Ag2S/MoS2@ZnPc heterojunction exhibited high MG absorption capability in the dark (64.95 mg g−1 at 30 min) and enhanced photodegradation ability under ultraviolet–visible light irradiation (96.3 % at 100 min). The practical experiments unveiled that the developed multifunctional photocatalyst could be employed to treat the wastewater containing pathogenic bacteria and organic pollutants via the thorough sterilization and photodegradation/adsorption of MG.

Coupled capture and photocatalysis of g-C3N4 based magnetic composites: Mechanism and disinfection activity against Staphylococcus aureus

The disinfection ability of g-C3N4 by photocatalysis is restricted, owing to its small surface area and rapid combination of holes (h+) and electrons (e−). Moreover, recycling of g-C3N4-based photocatalysts from aqueous solution is difficult, which increases the cost of application. In the present study, g-C3N4 was combined with magnetic biochar (MBC) by high temperature calcination to fabricate g-C3N4/MBC composites. The as-prepared g-C3N4/MBC composites acquired larger specific surface area, narrow bandgap, and broad-range of visible absorption capability. The g-C3N4/MBC composites showed good killing efficiency towards Staphylococcus aureus (S. aureus) under visible light irradiation. Efficient photocatalysis was achieved by the effective separation of e−/h+ within the g-C3N4/MBC composites. Moreover, the capture effect of MBC for S. aureus reduced the distance and increased the contact area between the g-C3N4/MBC composite and S. aureus. The g-C3N4/MBC-10 % showed notable stability and reusability over a broad pH range of 4–8 and in presence of different inorganic ions (Cl− and SO42−) and humic acid. After 5 cycles, the g-C3N4/MBC-10 % could still eliminate about 95 % of S. aureus cells. The g-C3N4/MBC-10 % was also highly effective in reducing the bacterial population in water samples taken from a nearby lake, thus showing considerable promise for use in water sterilization. In addition, g-C3N4/MBC composites were highly effective in eliminating the biofilm and inhibiting the growth of the new biofilm of S. aureus. The main active species in photocatalytic disinfection were determined, to be •OH, h+, and •O2−. This study would help to understand the capture and photocatalysis of g-C3N4 based composites for environmental applications.

Acidic Electrolyzed Water Maintains the Storage Quality of Postharvest Wampee Fruit by Activating the Disease Resistance.

Harvested wampee fruit is susceptible to disease, resulting in postharvest losses. Acidic electrolyzed water (AEW), a safe and innovative sterilization technology, plays a role in enhancing disease resistance in harvested produce. In this study, the efficacy of AEW in delaying wampee disease development was assessed, along with its association with disease resistance metabolism. Wampee fruit was treated with AEW (pH 2.5) at different available chlorine concentrations (ACCs) (20, 40, 60, and 80 mg/L) and subsequently stored at 25 °C for 8 days. Results revealed that 40 mg/L ACC in AEW (pH 2.5) was most effective in improving the postharvest quality of wampee fruit. Compared with control wampee fruit, those treated with 40 mg/L ACC in AEW exhibited lower incidence of fruit disease, higher pericarp lignin content, and higher activities of pericarp disease resistance enzymes (DREs), such as cinnamate-4-hydroxylase, phenylalanine ammonia-lyase, chitinase, β-1,3-glucanase, polyphenol oxidase, 4-coumarate CoA ligase, and cinnamyl alcohol dehydrogenase. These results suggested that AEW elevated DRE activities, promoted lignin accumulation, and ultimately enhanced disease resistance, suppressed disease development, and improved storage quality in harvested wampee fruit. Consequently, AEW emerged as a safe technology to mitigate the disease development and enhance the storage quality of harvested wampee fruit.

Flexible fiber composite functional materials based on Fe-MOFs nanozyme catalytic activity for efficient point-of-use water disinfection

Ensuring clean water sources is crucial for human health and safety. However, in underdeveloped areas and emergency situations, low-energy, convenient water disinfection technologies remain a significant challenge. Herein, a series of Fe-MIL-101@flexible fiber composites were designed and synthesized by in-situ cross-linking growth of Fe-MIL-101 metal–organic framework nanozymes on carboxymethyl cellulose (filter paper, cotton, gauze), as a class of point-of-use (POU) water disinfection modules with antibacterial efficacy, portability and biosecurity. The results show that the preparation method of water disinfection material is universal, and the most convenient Fe-MIL-101@composite carboxymethyl filter paper (Fe-MIL-101@CMFP) is outstanding. The combination of Fe-MIL-101 nanozyme with carboxymethyl filter paper (CMFP) is highly stable, even after 200 mechanical or manual frictions, the MOF particles does not fall off, and its flexibility, mechanical properties and filtration efficiency remain unchanged. Furthermore, Fe-MIL-101@CMFP exhibits remarkable simulated activity of peroxidase and oxidase, generating reactive oxygen species (ROS, •OH and O2•-), which effectively eliminate bacteria. Notably, Fe-MIL-101@CMFP filters have excellent bactericidal capability (about 99%), are equally effective on field water, and have no biosafety concerns. Such Fe-MIL-101@flexible fiber composite material, as a portable POU water disinfection and sterilization functional modules, is expected to solve the problem of distributed water disinfection as well as change the way of obtaining safe drinking water in underdeveloped areas and emergency situations.

Possibilities of using a corona electric discharge generator in the processes of water and surface sterilization

Possibilities of using a corona electric discharge generator in the processes of water and surface sterilization

Visible-Light-Driven Inactivation of Bacteria and H2 Generation Catalyzed by Oxygen-Vacancy-Rich One-Dimensional/Two-Dimensional W18O49/g-C3N4 Z-Scheme Heterostructures.

Z-scheme heterostructure-based photocatalysts consist of a reduction photocatalyst and an oxidation photocatalyst, enabling them to possess a high capacity for both reduction and oxidation. However, the coupling reaction between photocatalytic H2 generation through water reduction and sterilization using Z-scheme systems has been rarely reported. Herein, 1D W18O49 nanowires embedded over 2D g-C3N4 nanosheets are well-constructed as an integrated Z-scheme heterojunction. Experimental results and density functional theory calculations not only demonstrate the achievement of efficient interfacial charge separation and transport, leading to prolonged lifetime of photogenerated charge carriers, but also directly confirm the mechanism of Z-scheme charge transfer. As expected, the optimized W18O49/g-C3N4 nanostructure exhibits superior photocatalytic sterilization activity against Staphylococcus aureus as well as excellent H2 generation performance under visible-light irradiation (λ ≥ 420 nm). Due to its nontoxic nature, W18O49/g-C3N4 holds great potential in eradicating bacterial infections in living organisms.

Multi-scale modified PVDF/Ag@C layer based on dielectric doping and plasma treatment for high-performance triboelectric nanogenerators and self-powered water sterilization

The limitations of dielectric properties and surface electron affinity and the harsh environment including high humidity, high salt content, and biological fouling restricted the efficient ocean energy harvesting of triboelectric nanogenerators (TENGs). Here, Ag@C dielectric doping and two-step O2+CF4 plasma treatment are applied to achieve multi-scale modification of triboelectric materials. The coating of C shell avoided the agglomeration of Ag NPs. Besides, the amorphous C shell inhibited the formation of electron transport pathways, and the mechanism of suppressing dielectric loss of triboelectric layers were clarified via DFT calculations at the particle (Ag@C)-polymer (polyvinylidene difluoride, PVDF) interface. The surface charge density of plasma treated polyvinyl alcohol (PVA)-PVDF/Ag@C-based TENG (PT-TENG) increased from 64.26 µC/m2 to 216.60 µC/m2, representing a significant breakthrough in energy harvesting efficiency. The mechanism of enhanced triboelectric properties was investigated based on modified Overlapped Electron Cloud model. Besides, DFT was applied to analyze the reaction mechanism in depth and predict the products of chemically-surface modification process. The oxygen-containing functional groups introduced by O2 plasma treatment likely serve as a "bridge" for the second-step grafting, which helps to build a more convincing reaction mechanism. The superhydrophobic PVDF/Ag@C exhibited excellent moisture-resistance, salt-resistance, and anti-bioadhensive properties, with outstanding charge density (321.45 µC/m2) at 95% RH, making it very suitable for energy harvesting in harsh marine environments. Moreover, the water sterilization system based on PT-TENG demonstrated a high sterilization rate of 98.74%, which was significantly higher than conventional AC power (89.96%).

Comparative Evaluation of Microorganism Disinfection Methods for N95 Respirators

Background: An excessive demand for N95 respirators occurred during the SARS-CoV-2 pandemic. Therefore, health care workers were obligated to reuse N95 respirators, which were intended to be disposable. Aim: The primary objective of this study was to establish a standard procedure for safe disinfection or sterilization that does not affect the performance of an N95 respirator. Methods: As disinfection or sterilization methods, immersion in 70% ethanol, 0.1% hypochlorous acid, 0.3% peracetic acid, 0.2% alkyldiaminoethylglycine hydrochloride aqueous solution, hypochlorous acid water, or plant mineral-activated water, autoclaving, pasteurization and hydrogen peroxide plasma sterilization were used. After sterilization/disinfection, the filtration capacity of each N95 respirator was examined. Findings: The performance changes in the N95 respirator caused by each sterilization/disinfection method differed for each manufacturer’s product. Seventy percent ethanol, 0.1% sodium hypochlorite aqueous solution, 0.3% peracetic acid aqueous solution, autoclaving, hypochlorous acid water, and plant mineral-activated water significantly deteriorated the performance of N95 respirators. Performance degradation (increased permeability) was observed in 0.2% alkyldiaminoethylglycine hydrochloride aqueous solution and hydrogen peroxide plasma sterilization, and the permeation performance significantly deteriorated by 50–70% in all N95 respirators tested. Only pasteurization resulted in no deterioration in performance, even after five repeated sterilizations. Conclusion: Verification of sterilization/disinfection methods for the reuse of N95 respirators has shown that the currently recommended hydrogen peroxide plasma sterilization is inadequate as it increases permeability by more than 50% with a single treatment. In this study, pasteurization was found to be the optimal sterilization method.

Cold sterilization of coconut water by membrane technology and UV-C

Coconut water contains amino acids, vitamins, antioxidants, and mineral, which are beneficial for human health. However, rapid degradation of coconut water due to the presence of protein, fat, and microbes has led to short shelf life and coconut water’s rancidity. Sterilization of coconut water by heat treatment has been proven to be effective in microorganism elimination, but results in major changes of coconut water’s sensory attributes. In this research, cold sterilization of coconut water was conducted by using ultrafiltration membrane and UV-C to preserve the sensory properties and nutritional components in coconut water. The radiation dose of UV-C and operating pressure of ultrafiltration membrane was varied to obtain the optimum operating condition. The sterilization process by UV-C did not remove fat and protein, which are the rancidity-causing components. In ultrafiltration sterilization, fat and protein can be removed by 74% and 31.37%. Superior microorganism elimination by ultrafiltration was obtained at 99.9999%, compared to that by UV-C at 90%. The ultrafiltration also retained the coconut water’s pH, total soluble solid, and flavor, while improved its clarity. At optimum operating pressure of 0.25 bar, the coconut water’s shelf life of 3 days, according to the Standar Nasional Indonesia (SNI), can be achieved.

Characterization of the Photothermal Response in Nanocomposite Silica Aerogel Materials with Thin Metal Films

The photothermal effect, whereby light energy is converted into thermal energy when absorbed in a material, is a phenomenon that has many potential applications including solar-driven water heating and purification, and radiative heat transfer. Recently, porous materials have been tailored to exhibit the photothermal effect to be used for interfacial water evaporation and sterilization. In this work we provide the characterization of the solar-driven photothermal effect on nanocomposite aerogel materials. Aerogels exhibit a unique combination of properties that can enhance their utility as a photothermal material. Due to their inherently low density and thermal conductivity, and their exceptional insulative properties, photothermal heat generated within an aerogel can remain trapped. This work presents the photothermal effect in nanocomposite aerogels fabricated by sputtering metal and metal oxide films onto and into aerogels materials. By sputtering metal and metal oxides in a high vacuum environment and directing it towards an aerogel substrate using a magnetron, we were able to deposit thin films onto the surface of an aerogel. The composite aerogels are characterized using scanning electron microscopy (SEM) to assess the depth of the sputtered material into the aerogel pores. The reflectance and transmittance of the aerogel composites are measured using UV-Vis spectroscopy. The photothermal effect in aerogel composites is measured using thermal imaging. Our results show that the photothermal response of the composite aerogels can be tuned by varying the thickness and composition of the deposited films. Overall, our study demonstrates the potential of using magnetron sputtering to create composite aerogels with tailored photothermal properties. This opens new opportunities for a wide range of applications such as water and air heating and purification, water desalination, and solar energy harvesting devices.

Oxygen vacancy-rich Ag/CuO nanoarray mesh fabricated by laser ablation for efficient bacterial inactivation

The contamination of drinking water by microbes is a critical health concern, underscoring the need for safe, reliable, and efficient methods to treat pathogenic microorganisms. While most sterilization materials are available in powder form, this presents safety risks and challenges in recycling. Herein, this study reports the preparation of an innovative copper oxide supported silver monolithic nanoarray mesh with abundant oxygen vacancies (Ag/CuO-VO) by laser ablation. The instantaneous high temperature caused by laser ablation preserves the material's original structure while generating oxygen vacancies on the CuO surface. The Ag/CuO-VO mesh demonstrated a remarkable ability to inactivate over 99% of Escherichia coli (E. Coli) within 20 min. The oxygen vacancies in the Ag/CuO-VO enhance interactions between oxygen species and the Ag/CuO-VO, leading to the accumulation of large amounts of reactive oxygen species (ROS). The generated ROS effectively disrupt both layers of the bacterial cell wall - the peptidoglycan and the phospholipid - as confirmed by Fourier Transform Infrared (FTIR) spectroscopy, culminating in cell death. This research presents a monolithic material capable of inactivating pathogenic microorganisms efficiently, offering a significant advancement in water sterilization technology.

Optimal UV Quantity for a Ballast Water Treatment System for Compliance with Imo Standards

Abstract Ballast water management is an effective measure to ensure that organisms, bacteria and viruses do not migrate with the ballast water to other areas. In 2004, the International Maritime Organization adopted the International Convention on the Control and Management of Ballast Water and Ship Sediments, which regulates issues related to ballast water management. Many technologies have been researched and developed, and of these, the use of UV rays in combination with filter membranes has been shown to have many advantages and to meet the requirements of the Convention. However, the use of UV furnaces in ballast water treatment systems requires a very large capacity, involving the use of many high-power UV lamps. This not only consumes large amounts of electrical energy, but is also expensive. It is therefore necessary to find an optimal algorithm to enable the UV radiation for the UV controller in the ballast water sterilisation process to be controlled in a reasonable and effective manner. This controller helps to prolong the life of the UV lamp, reduce power consumption and ensure effective sterilisation. This paper presents a UV control algorithm and a controller for a UV furnace for a ballast water treatment system installed on a ship. The results of tests on vessels illustrate the effect of the proposed UV controller.