Oxidation-reduction Potential Research Articles

Evaluation of the bactericidal activity of plasma-activated NaCl solution (PAN) against foodborne pathogens: Inactivation mechanism and application to mackerel

The objective of this study was to assess the bactericidal effect of plasma-activated NaCl solution (PAN) against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and apply PAN as a brine salting solution for mackerel. To enhance the bactericidal effect of plasma-activated water (PAW), NaCl solutions (0, 3.5, 7, and 10 %) were treated with plasma for 20 and 40 min to generate PAN. Plasma-activated glycerol solution (PAG) was also included to evaluate the influence of water activity on plasma activation and its effect on microbial activity. Physicochemical analysis revealed that elevating the NaCl concentration of PAN led to a decrease in pH, an increase in oxidation–reduction potential, and higher levels of reactive species such as H2O2 and HOCl. PAN showed greater antibacterial activity compared to PAW and PAG, except for L. monocytogenes, where 40 min activation time and treatment time exceeding 20 min was required for significantly higher reduction to occur. PAN exhibited greater antibacterial activity at higher NaCl concentrations, which was attributed to increased ionic strength and reactive chlorine species. Additionally, we evaluated the microbial mechanisms of PAN by assessing cellular damage and alterations. The common observation across the three pathogens was that PAN resulted in increased cell membrane damage, reduced intermembrane enzyme activity, higher intracellular ROS levels, and changes in zeta potential values, while DNA damage was observed only in PAN-treated L. monocytogenes. Furthermore, when PAW and PAN were stored for up to four weeks, PAN showed higher efficacy compared to PAW. 10 % PAN was also effective against foodborne pathogens on mackerel, achieving log reductions of 3.62 for E. coli O157:H7, 4.62 for S. Typhimurium, and 3.18 for L. monocytogenes after a 20 min treatment without adversely affecting quality. Our results demonstrated the antibacterial activity and action mechanism of PAN, presenting its potential application in the seafood industry.

Nuclear Magnetic Resonance (NMR) and Density Functional Theory (DFT) Study of Water Clusters of Hydrogen-Rich Water (HRW)

The present study investigated the 1H Nuclear Magnetic Resonance (NMR) spectra of hydrogen-rich water (HRW) produced using the EVObooster device. The analyzed HRW has pH = 7.1 ± 0.11, oxidation–reduction potential (ORP) of (−450 ± 11) mV, and a dissolved hydrogen concentration of 1.2 ppm. The control sample was tap water filtered by patented technology. A 600 NMR spectrometer was used to measure NMR spectra. Isotropic 1H nuclear magnetic shielding constants of the most stable clusters (H2O)n with n from 3 to 28 have been calculated by employing the gauge-including-atomic-orbital (GIAO) method at the MPW1PW91/6-311+G(2d,p) density function level of theory (DFT). The HRW chemical shift is downfield (higher chemical shifts) due to increased hydrogen bonding. More extensive formations were formed in HRW than in control filtered tap water. The exchange of protons between water molecules is rapid in HRW, and the 1H NMR spectra are in fast exchange mode. Therefore, we averaged the calculated chemical shifts of the investigated water clusters. As the size of the clusters increases, the number of hydrogen bonds increases, which leads to an increase in the chemical shift. The dependence is an exponential saturation that occurs at about N = 10. The modeled clusters in HRW are structurally stabilized, suggesting well-ordered hydrogen bonds. In the article, different processes are described for the transport of water molecules and clusters. These processes are with aquaporins, fusion pores, gap-junction channels, and WAT FOUR model. The exponential trend of saturation shows the dynamics of water molecules in clusters. In our research, the chemical shift of 4.257 ppm indicates stable water clusters of 4–5 water molecules. The pentagonal rings in dodecahedron cage H3O+(H2O)20 allow for an optimal arrangement of hydrogen bonds that minimizes the potential energy.

Design, perspectives, and challenges of modification strategies for alkali metal anodes

Abstract. The alkali metal anode has emerged as a focal point of research due to its extremely low oxidation-reduction potential and high theoretical specific capacity. However, challenges such as unstable solid electrolyte interphase (SEI), infinite volume expansion, and uncontrollable dendrite growth result in low coulombic efficiency and irreversible losses during the deposition and stripping processes. To address these issues, various effective strategies have been proposed to protect the alkali metal anode and achieve dendrite-free growth. In this review, we summarize recent advancements in enhancement strategies for alkali metal anodes, including the construction of three-dimensional current collectors and interface engineering. Specifically, we delve into the development of carbon-based current collectors with various dimensions and structures and the application of interface engineering techniques to tackle the challenges of unstable SEI, volume changes, and dendrite growth. Furthermore, we explore advanced characterization techniques that provide deeper insights into the reaction mechanisms and behavior of these enhancement strategies. Finally, we discuss the current limitations and future research directions in protecting alkali metal anodes, aiming to provide valuable insights into the study of dendrite growth and the development of effective protection strategies for alkali metal anodes.

Relationship Between Aquatic Factors and Sulfide and Ferrous Iron in Black Bloom in Lakes: A Case Study of a Eutrophic Lake in Eastern China

Black bloom is a very serious water pollution phenomenon in eutrophic lakes, with Fe(II) and S(−II) being the key limiting factors for this problem. In this paper, three different machine learning methods, namely, Random Forest (RF), Gaussian Mixture Model (GMM), and Bayesian Network (BN), were used to explore the complex interactions among Fe(II), S(−II), and other aquatic factors in the estuary of Chaohu Lake to better characterize and monitor water degradation by black bloom. The results of RF showed that total nitrogen (TN), ammonia, total phosphorous (TP), suspended sediment concentration (SSC), and oxidation–reduction potential (ORP), which were chosen from 11 factors, had the most important relationships with Fe(II) and S(−II). The 69 sampling sites were divided in three groups identified as worst, worse, and bad according to the observed values of seven factors using the GMM. Then, the BN model was applied to three observation groups. The results showed that the structures of the interaction networks were different between the groups. S(−II) controlled only SSC production in the bad and worse group sites, while SSC was determined by both S(−II) and Fe(II) in the worst group. Ammonia and TN exhibited the most direct importance for S(−II) and Fe(II) production in all observation groups. According to the indications from the BNs, potential management strategies for different water pollution conditions were developed. Finally, the threshold values of Fe(II), S(−II), TP, ammonia, TN, SSC, and ORP, which were 0.80 mg/L, 0.04 mg/L, 0.45 mg/L, 3.44 mg/L, 4.15 mg/L, 55 mg/L, and 135 mv, respectively, were determined on the basis of the BN models. These values will be helpful to develop accurate strategies of oxygenation to quickly eliminate black bloom in the lake.

The impact of temperature on the growth of Pseudomonas aeruginosa in mineral waters originated from different wells: A predictive approach

This study aimed to evaluate the behavior of Pseudomonas aeruginosa (PSA) in natural mineral water sourced from three different extraction wells and stored at various temperatures (10, 12, 20, 23, and 30 °C) to calculate the kinetic growth parameters of this microorganism through predictive modeling. The physicochemical characterization of waters was also evaluated at the time of collection, and included the analysis of 40 different minerals, and quality parameters such as pH, conductivity, oxidation-reduction potential (ORP), total dissolved solids (TDS), salinity (PSU), and temperature (T). PSA survived in raw mineral water incubated at 12, 20, 23, and 30 °C; however, no growth was observed at 10 °C. Growth curves started with an initial population of ~ 2.5–3 log CFU/mL, and final PSA populations ranged from 3.5 to 4.9 log CFU/mL. The maximum specific growth rate (μmax) at 30 °C varied among the wells, with Well P-07 showing the highest growth rate (0.2 h−1), followed by Well P-08 (0.195 h−1) and well P-01 (0.133 h−1). At 12 °C, well P-01 exhibited the highest growth rate (μmax = 0.22 h−1), indicating a influence of mineral composition in the growth of PSA. The lag time (λ) also varied, with minimum values of 2.4 ± 0.1 h at 30 °C and maximum values of 41.6 ± 0.2 h at 12 °C. From these primary estimated parameters, it was possible to obtain five robust secondary models to describe the influence of temperature on the maximum growth rates and lag phase of PSA in the well. The estimated PSA growth parameters at 20 and 23 °C were subjected to a hierarchical cluster analysis and correlation plots to verify the influence of the physicochemical composition of the waters on the PSA behavior at each well's specific annual average temperature. This analysis confirmed a positive relationship (p < 0.05) between the presence of minerals (Ca, Fe, Sr, Mn, Na) and ions (SO4−3, Cl−) and the PSA lag phase time. These results underscore the need for tailored water quality management strategies that consider chemical composition and temperature to address specific microbial contamination risks.

Illuminating bioprocess responses to metal-based nanoparticles addition along hydrogen and methane production pathways: A review.

Recent research has discussed the positive impacts of metal-based nanoparticles (NPs) on bioprocesses producing either hydrogen (H2) or methane (CH4). The enhancement has been explained by mechanisms such as direct interspecies electron transfer (DIET), metal corrosion, and dissimilatory reduction. Such interactions could induce further benefits, such as controlling oxidation-reduction potential (ORP), mitigating toxicants, promoting enzymatic activity, and altering the microbiome, which have not yet been comprehensively discussed. Factors like metal type, oxidation state, and size of NPs are crucial for their reactivity and corresponding responses. This review discusses how different redox potentials of metals can regulate metabolic pathways and how NPs and their reactive ions can eliminate toxicants (e.g., sulfate) and enhance the activity of intra- and extracellular enzymes. The enrichment of responsive microorganisms in correlation with NPs is further discussed. A better understanding of the multifaceted role of metal-based NPs can guide potential new incorporation strategies to improve bioprocesses.

The aeration and dredging stimulate the reduction of pollution and carbon emissions in a sediment microcosm study

Sediment dredging and aeration are used as important technical measures to remediate internal loading of sediment in polluted rivers. However, previous studies have overlooked the impact of dredging and aeration on Greenhouse gases (GHGs) emission. We established three aeration rate(six different aeration intervals), one dredging treatment to investigate the effect of aeration and dredging on pollutant removals and CO2, CH4 and N2O emissions. The results indicated the pollutants and GHGs at 2.4, 3.4, 4.4 L min−1 aeration rates reached collaborative emission reduction after more than 3 h or within 1.5 h. Meanwhile, the GHGs fluxes after aeration decreased with the increasing aeration rate, with the mean CO2, CH4 and N2O fluxes of 69.74, 0.16, 7.53 mg m−2 h−1 and 33.64, 0.09, 4.17 mg m−2 h−1 before and after aeration, respectively. With respect to dredging, the pollutants and N2O reached synergic effects between reduction of pollution and carbon emissions after 1 h dredging. Specifically, the CO2 and CH4 emissions after dredging was lower than those of before dredging, but the N2O emissions was higher than those of before dredging. In addition, our analysis revealed that the dissolved oxygen (DO), oxidation-reduction potential (ORP), available potassium (AK) and ammoniacal nitrogen (NH4+-N) in the sediment influenced GHGs fluxes at the water-air interface in the aeration. Our study indicated moderate aeration and dredging can achieve the synergistic effect in reducing pollution and carbon emissions.

Exploring Spatial Dynamics of Water Quality in a Tropical Lake Affected by Aquaculture

Lake Maninjau, like many surface water bodies worldwide, faces significant water pollution challenges due to extensive aquaculture activities, making it an ideal site to study the impact of fish farming on water quality, which has contributed to eutrophication and declining water quality. This study investigates the physicochemical parameters and pollution levels in the lake, aiming to provide insights into its environmental health. In August 2022, a comprehensive sampling campaign was undertaken at nine stations within the upper layers of open water and littoral zones of Lake Maninjau. In situ measurements, including temperature, dissolved oxygen, and pH, were conducted, accompanied by water sample collection for laboratory analysis of trace elements and heavy metals. Our study revealed notable variability in water parameters across different sites, with surface water layers exhibiting the greatest differences. While certain parameters such as temperature and conductivity remain relatively stable, pH levels show a decreasing trend with increasing water depth. Dissolved oxygen levels vary widely, while oxidation–reduction potential indicates water pollution, particularly in littoral zones. Potassium dominance within cations likely suggests anthropogenic influences, notably from aquaculture activities, that may also contribute to nutrient enrichment and heavy metal pollution. Elevated levels of total nitrogen and ammonia underscore the lake’s moderate pollution levels, with heavy metals such as mercury exceeding permissible limits, posing risks to aquatic life and human health.

Green Pathway of Urea Synthesis Through Plasma–Ice Interaction: Optimization and Mechanistic Insights With N2 + CO2 and NH3 + CO2 Gas Mixtures

ABSTRACTThis study presents a green approach for urea synthesis using plasma–ice interaction with N₂ + CO₂ and NH₃ + CO₂ gas mixtures. Plasma characterization via electrical and optical emission spectroscopy revealed that urea formation involves complex reactions driven by high‐energy species, producing reactive nitrogen and carbon intermediates. Plasma‐treated ice exhibited increased pH, electrical conductivity (EC), and reduced oxidation–reduction potential (ORP). Optimization of parameters, especially treatment time, significantly influenced urea formation. The NH₃ + CO₂ plasma produced a higher urea concentration (7.7 mg L−1) compared to the N₂ + CO₂ plasma (0.55 mg L−1) due to ammonia's greater reactivity. This method offers a sustainable, energy‐efficient alternative to traditional urea synthesis processes.

Effects of oxidation reduction potential levels on bacterial density in Portuguese oysters (Crassostrea angulata) utilising a sonoelectrochemical depuration system

ABSTRACT The consumption of raw oysters is on the rise and poses a significant health risk because of the presence of bacteria such as Escherichia coli, Salmonella spp., and Vibrio spp. Sonoelectrochemical technology offers a promising solution by creating nanobubbles charged with negative ions, which effectively kill bacteria in oysters without affecting human health, and is also environmentally friendly. This study evaluated the bacterial reduction capability of this technology on Portuguese oysters (Crassostrea angulata) using different oxidation redox potential (ORP) levels of 450, 600 and 750 mV compared with clean seawater (control) after 8, 16 and 24 hours. The results showed that extended exposure time did not significantly decrease E. coli and Salmonella spp. densities, except for the 750 mV treatment. The ORP level of 750 mV for 16 hours was the most effective in reducing bacterial population in oysters with total Vibrio, E. coli and Salmonella spp. reduced by 1.14, 0.95, and 0.85 logCFU/g, respectively. Further research is needed to optimise oyster depuration using sonoelectrochemical technology to enhance its efficiency and practical application.

Hydrological controls of a riparian wetland based on stable isotope data and model simulations.

Isotopic evidence of groundwater and stream water is frequently used to investigate water exchanges with groundwater. Monthly sampling of rain, stream water, and groundwater was conducted at Tims Branch watershed in South Carolina for the oxygen and hydrogen stable isotope (δ2H and δ18O) measurement, as well as pH and oxidation-reduction potential (ORP). Together with a mass balance perspective, it was determined that it takes a few weeks to one month for groundwater in the hyporheic zone to fully exchange with stream water. From hydrodynamic modelling, we show that substantial (up to 70 %) groundwater exchange occurs at gaining and losing sites. Groundwater exfiltration, i.e. inflow into stream water, contributes up to 4 % to stream water, with the remainder from upstream exfiltration. A 2-4 % per day renewal rate of adjacent groundwater would indirectly indicate a groundwater residence time in the order of half a month to a full month (assuming either a well-mixed case or large dispersion rate in pulse flow case), in agreement with a greatly reduced variability of δ2H and δ18O of groundwater compared to stream water and rain. This reduced variability of stable isotope signal from groundwater confirms our hypothesis that riparian groundwater mixing at Tims Branch is more of a mixed type rather than a pulse flow type. A monthly time scale is sufficient for groundwater to become anoxic at exit points into stream water resulting in the episodic production of natural organic matter- and iron-rich flocs upon oxidation.

Quality and safety of fresh Spirulina (Arthrospira platensis) maintained by bubbling plasma-activated air

Spirulina (Arthrospira platensis) is a blue-green alga valued for its protein, phycocyanin, and other bioactive compounds. However, its commercial outdoor cultivation makes it susceptible to microbial contamination, affecting both biomass productivity and quality. Additionally, most commercial Spirulina is sold in dried forms such as powder, flakes, and tablets, which can degrade these bioactive components. To address these issues, non-thermal techniques, such as cold plasma, offer a promising solution by effectively reducing microbial contamination while preserving product quality without the need for drying. This study investigated the potential of bubbling cold plasma-activated (BCPA) air through freshly grown Spirulina to reduce microbial contamination and maintain quality during storage. Spirulina grown in an outdoor paddle-wheel driven pond was harvested in paste form, resuspended in deionized water, treated with plasma-activated air and stored at 4 °C for 28 days. The treatment significantly reduced microbial contamination and maintained Spirulina biomass and pigment contents compared to untreated control. The cellular structure remained intact, and colour changes were minimal in the treated samples when compared to the controls. Moreover, the Spirulina suspension pH became acidic (pH = 4), and oxidation-reduction potential was significantly higher (>150 mV) in treated samples compared to controls throughout the storage period. The results demonstrate the potential for BCPA air to maintain the quality of fresh Spirulina. This finding may have significant applications in the Spirulina industry for offering customers fresh products rather than dried Spirulina.

Long-Term Storage Stability of Neutral Electrolyzed Water by Two-Stage Electrolysis: Optimal Storage Conditions for Intraoral Use

Electrolyzed water mainly containing hypochlorous acid is widely used because of its strong microbicidal effects, biosafety, and eco-friendliness. For frequent use in intraoral treatments, we focused on neutral electrolyzed water (NW) produced using two-stage electrolysis and investigated its storage stability. For standard-concentration NW preparations with a free available chlorine concentration (ACC) of 25, 35, and 50 mg/L and high-concentration NW preparations (100, 200, 300, 500, and 1000 mg/L), the changes in the pH, oxidation reduction potential, and ACC during a 126-day storage period and the bactericidal efficacies after storage were examined. Storage under non-shaded conditions at room temperature (LRT) and a higher ACC substantially altered the properties of the NW. NW (≤300 mg/L) had a pH of 5.9–7.3 even after storage under LRT; however, NW with a higher ACC (500 and 1000 mg/L) had a pH ˂ 5.5, critical for human enamel, even under shaded and refrigerated conditions (SLW). Only NW (25 mg/L) stored under LRT decreased the bactericidal effect (removal rate: 99.8%). When stored for use in intraoral treatments, NW should be prepared with an ACC of 25–300 mg/L and stored in SLW. It is suggested that stored NW, especially when diluting it, should be checked to ensure it maintains the properties appropriate for every intended purpose.

Kinetic features and mechanism of scorodite formation via multivalent iron source from arsenic-bearing solution

Arsenic-bearing wastes from non-ferrous metallurgy exhibit poor stability during long-term storage, and are transferred as pollutants to the atmosphere and groundwater, thereby, threatening human health and ecological security. Immobilising arsenic as scorodite crystals via a multivalent iron source (Fe(OH)3-FeSO4·7 H2O) is one effective approach for controlling arsenic pollution. However, the kinetic features and mechanisms of this method have not yet been revealed, thereby, necessitating further research. Herein, the kinetics of scorodite generation influenced by the initial pH, Fe/As ratio, Fe(III)/Fe(II) ratio, and reaction temperature were investigated. Prominent features included variations in the minimum pH, oxidation–reduction potential (ORP) platform, Fe/As ratio (1.0), and the delay or advance of scorodite generation. The complicated mechanism of scorodite formation can be divided into coordinated polymerisation, acidic Fe(OH)3 dissolution, polymer oxidation, Fe(II) oxidation, and scorodite crystallisation. The fast coordinated polymerisation of precursors ([Fe(H2O)4(H2AsO4)]nn+) in stage I resulted in a decrease in pH; Fe(OH)3@scorodite and Fe(H2O)2AsO4 basic units were formed via the oxidation of ionic Fe(III) in stage II. Furthermore, regular octahedral scorodite was generated from two sources: the crystallisation of Fe(H2O)2AsO4 basic units and Ostwald ripening of flaky scorodite from Fe(III)–As(V) precipitates at stage III. The Fe(II) in the polymers was mainly oxidised by ferric ions generated from the oxidation of ferrous ions via dissolved O2 from the oxygen gas. Fe(II) ions as carriers for transferring electrons from O2 to polymers. Scorodite formation was controlled by the oxidation of Fe(II) by oxygen gas. Overall, this study provides guidance for the effective immobilisation of arsenic wastes into scorodite via multivalent iron sources to eliminate arsenic pollution.

Semen static oxidation-reduction potential is not helpful in evaluating male fertility.

Infertility affects a significant percentage of couples worldwide, with male infertility contributing substantially in a considerable number of cases. Research indicates that oxidative stress is a critical factor impacting male fertility. To explore the relationship between semen static oxidation-reduction potential (sORP), sperm parameters, and validated biomarkers of oxidative stress in infertile men. This cross-sectional study involved 202 men diagnosed with idiopathic male factor infertility and male partners from couples with unexplained infertility. Multivariable linear regression to query the associations between sORP, sperm parameters, and oxidative aggression biomarkers (lipid peroxidation, mitochondrial membrane potential, annexin V, and sperm DNA fragmentation). SORP has no linear association with any semen analysis parameter. Furthermore, its relationship with validated biomarkers of oxidative stress was inconsistent. sORP was inversely related to lipid peroxidation (multivariable linear regression coefficient: -0.64), positively associated with sperm DNA fragmentation (multivariable linear regression coefficient: 3.20), and unrelated to mitochondrial membrane potential or annexin V. There is no clear or consistent relationship between sORP and validated oxidative aggression biomarkers or sperm parameters. Our findings suggest that sORP is unlikely to be helpful in the evaluation of a male with idiopathic infertility.

Understanding the interaction between soil ORP and enzyme activity: How does wetland type affect constructed wetland performance for the advanced treatment of swine wastewater?

Constructed wetlands (CWs) are widely used for the advanced treatment of swine wastewater. Wetland type is the most critical parameter for engineering applications; therefore, the performance of horizontal/vertical subsurface flow CWs (HSFCWs and VSFCWs) was explored over one year of operation. The effects of five antibiotics (40 μg/L each), copper (Cu, 1.0 mg/L), and their combination on CW performance and soil oxidation–reduction potential (ORP) and enzyme activity were investigated. The annual removal efficiencies of HSFCWs and VSFCWs for total organic carbon (TOC), nitrogen, and phosphorus were 72.03 %–84.49 % and 87.15 %–90.72 %, for antibiotics were 91.35 %–99.52 % and 87.33 %–99.57 %, and for Cu were 97.37 %–97.44 % and 95.52 %–96.85 %, respectively. The CWs removed antibiotics through substrate adsorption, plant absorption, and biodegradation. Total antibiotic residues in HSFCW and VSFCW soils ranged from 6.29 to 17.31 and 24.57 to 589.07 μg/kg, respectively, and enrofloxacin and roxithromycin posed medium and high risks in VSFCW non-rhizosphere soil. The amount of residual antibiotics in Phragmites australis parts was in the order of fibrous roots > rhizomes > aboveground. ORP and enzyme activities were greater in rhizosphere soil than in non-rhizosphere soil and greater in the VSFCWs than in the HSFCWs. CW performance and soil enzyme activities decreased under the stress of antibiotics and coexistence of antibiotics and Cu. These findings advance our knowledge of CW design, elucidate the unique advantages of CWs, and offer efficient operation strategies for swine wastewater advanced treatment, helping researchers recognize the adverse effects of antibiotics on CWs.

Pre-ozonation coupled with forward osmosis with fertilizer as draw solution for simultaneous wastewater treatment and agricultural irrigation

Membrane-based processes have emerged as effective solutions for treating tannery wastewater. Persistent membrane fouling remains a significant obstacle to long-term operational sustainability, and residual pollutants often persist in the treated effluent. To address these challenges, we investigated an integrated ozone-forward osmosis (O3-FO) process, with a focus on evaluating the efficacy of pre-ozonation in alleviating membrane fouling, as well as exploring the possibilities of this integrated process for the reuse of tannery wastewater. Fertilizer, specifically 2 M Ca(NO3)2, served as the draw solution (DS) in this process. The findings reveal that the integrated system demonstrated remarkable pollutant retention capabilities. Notably, no metal was detected in the fertilizer. Therefore, the integrated process not only dilutes the fertilizer but also minimizes the risk of heavy metal contamination to both crops and soil. Furthermore, pre-ozonation effectively mitigated membrane fouling, resulting in an increase in membrane flux with a maximum increase of 20.98 % at 0.6 L/min. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed pre-ozonation has the most significant impact on four parameters: water flux (Jw), chemical oxygen demand (COD), fouling resistance (Rf) and oxidation reduction potential (ORP). Meanwhile, ammonium nitrogen (NH4-N) variation, dissolved organic carbon (DOC) variation and ORP played an important role in the four systems. Multi-criteria decision analysis (MCDA) showed that the 0.2 L/min O3-FO system achieved the highest score (0.66), followed by 0.6 L/min (0.53), 0.4 L/min (0.41) and 0 L/min (0.29). This research offers a theoretical framework for the synergistic integration of advanced oxidation and membrane technology in the treatment of industrial wastewater.

Greenhouse Gas Emissions Characteristics and Driving Factors Analysis in the Eutrophic Saline Lake Daihai Lake

To investigate the greenhouse gas emission characteristics and driving factors of eutrophic saline lakes in northern China, considering Daihai Lake in Inner Mongolia as an example, 10 monitoring sites were selected based on hydrological distribution characteristics in April, July, and October 2023. Using headspace gas chromatography and modeling methods, dissolved concentrations and exchange fluxes of carbon dioxide （CO2）, methane （CH4）, and nitrous oxide （N2O） were determined in the nearshore zone, open lake area, and lake center surface water. During the study period, Daihai Lake exhibited significant seasonal variations in greenhouse gas concentration and flux. The average concentrations of CO2, CH4, and N2O in surface water were （26.52 ± 17.58） μmol·L-1, （282.30 ± 172.30） nmol·L-1, and （9.09 ± 1.64） nmol·L-1, respectively. The average fluxes were （5.29 ± 11.98） mmol·（m2·d）-1, （178.24 ± 63.34） μmol·（m2·d）-1, and （-0.74 ± 1.28） μmol·（m2·d）-1, with cumulative emissions of 50 770.77, 543.52, -4.21 kg·km-2 and a global warming potential （expressed in CO2-equivalent） of 50 770.77, 15 218.49, -1 254.48 kg·km-2. Daihai Lake acted as a source of atmospheric CO2 and CH4 but a sink for N2O during the study period. Correlation and stepwise regression analyses revealed that pH and total dissolved solids （TDS） influenced CO2 concentration and flux, while the factors affecting CH4 were water temperature （WT）, water depth （WD）, wind speed （WS）, oxidation-reduction potential （ORP）, and total nitrogen （TN）. For N2O, the influencing factors were WT, WS, and TN. Additionally, Daihai Lake's eutrophication and salinity characteristics influenced the generation and emission of greenhouse gases. This study provides insights into the greenhouse gas dynamics and environmental factors in eutrophic saline lakes like Daihai Lake.

Nitrite manipulation in water by structure change of plasma electrolysis reactor

In this study, experimental reactors for cathodic nitrogen plasma electrolysis were designed by the composition of galvanic (voltaic) and electrolytic cells with wide and narrow connectors filled with tap water and agar solutions. The designed reactor can be used to simultaneously perform and manage nitrification in acidic and alkaline environments. According to the reactor’s performance, it can be installed on the irrigation system and used depending on the soil pH of the fields for delivering water and nitrogen species that are effective in growth. The nitrification process was investigated by choosing the optimal reactor with a wide connector based on different changes in oxidation-reduction potential and pH on the anode and cathode sides. The nitrite concentration changed directly with ammonium and nitrate concentrations on the cathode side. It changed inversely and directly with ammonium and nitrate concentrations on the anode side respectively. Nitrite concentration decreased from 5.387 ppm with water connector, to 0.326 ppm with 20% agar solution, and 0.314 ppm with 30% agar solution connectors on the anode side. It increased from 0 ppm to 0.191 ppm with a water connector, 0.405 ppm with 20% agar solution, and 7.454 ppm with 30% agar solution connectors on the cathode side.

Real-Time Monitoring of Seawater Quality Parameters in Ayia Napa, Cyprus

Real-time monitoring systems are crucial for the comprehensive management of operations and processes, as well as for assessing the impacts of coastal infrastructures on the marine environment. These systems not only support environmental protection and data-driven decision-making but also enable the early detection of adverse events and the issuance of timely warnings for prompt responses. Although water quality is a critical parameter in this monitoring framework, there are currently limited permanent systems in place dedicated to maintaining these objectives. Even fewer systems leverage their data for research purposes, leading to a gap in the literature regarding effective processing approaches for real-time water quality data. In this context, this study presents a real-time water quality monitoring system integrated into a broader in-field laboratory installed at a coastal area off the coast of Ayia Napa, Cyprus, as well as an initial measured data set of different qualitative quantities. It proposes a holistic approach for post-processing real-time seawater quality data, employing both time and frequency domain analyses, alongside filtering techniques. The study discusses the advantages of each method and emphasizes the importance of their combined use. Utilizing data collected from a three-month operational period, the study assesses the current state of marine seawater quality and examines both temporal and cyclic variations in various seawater quality parameters. The findings reveal that the examined seawater parameters are within reasonable values, indicating that the construction and operation of a nearby marina and the necessary infrastructures (e.g., breakwater) did not affect the seawater quality in the area. Additionally, the study identifies pronounced daily cyclic responses in different seawater quality parameters, including temperature, density, pH, dissolved oxygen, and turbidity. Finally, notable correlations are observed between temperature and dissolved oxygen, temperature and conductivity, oxidation–reduction potential (ORP) and salinity, ORP and dissolved oxygen, and ORP and TDS.