Peroxide Process Research Articles

Effectiveness of biologically active substances added to sturgeon feeds

The purpose of this research was to study the effect of the vitamin‐mineral complex E‐selenium and the probiotic preparation Bacell when added to industrial feed on the fish‐breeding‐biological and physiological‐ biochemical parameters of juvenile sterlet‐beluga hybrids when reared in cages.The duration of the experiment was 45 days. In experimental option 1, the fish were fed with basic compound feed with the addition of E‐selenium (300 μg selenium/kg of feed), in experimental option 2, the fish were fed with basic compound feed with the addition of E‐selenium (300 μg selenium/kg of feed) and the Bacell preparation (0.2 % by weight of dry food). The control variant was fed with basic feed.The absolute increase in the experimental variants was 13.0–25.0 % higher than in the control. Hematological parameters varied – in some cases with a high degree of significance. In particular, hemoglobin increased by 5.6–13 %, blood serum protein by 0.42–12.6 %, cholesterol by 9.8–16.3 % in the experimental variants and by 70.5 % in the control, due to the presence of a high degree of stress in control fish. At the same time, in fish experiments the effects of stress factors were suppressed by antioxidants. Preventive doses of microelements, vitamins and probiotics reduce and stabilise peroxide processes and contribute to the maintenance of good physiological condition of fish kept in artificial conditions.

Effects of water matrices on the removal of oxytetracycline antibiotic and total organic carbon (TOC) using four different oxidation processes

Antibiotic compounds are actively discharged into aquatic environments through wastewater, potentially contributing to the emergence of drug-resistant bacteria and associated health issues. Oxidation processes (OPs), including advanced oxidation processes (AOPs), have gained attention as promising methods for removing antibiotics from wastewater. In this study, we comprehensively compared the efficiencies of removing oxytetracycline (OTC) and total organic carbon (TOC) by four OPs. These processes include three AOPs: the ozone/hydrogen peroxide process (O3/H2O2), photo-Fenton reaction (Fe/H2O2/UV), and Fenton reaction (Fe/H2O2), and ozonation (O3) as a conventional OP. To evaluate the effects of different water matrices, the degradation experiments were conducted using ultrapure water and actual wastewater. All four OPs achieved over 99% OTC degradation within 15 minutes of the experiment. The photo-Fenton reaction exhibited the highest TOC removal rates (66% for ultrapure water and 74% for actual wastewater) after 210 minutes. Conversely, ozonation resulted in the lowest TOC removal rates (7% for ultrapure water and 10% for actual wastewater). Therefore, this study suggests that the photo-Fenton reaction may be most suitable for degrading OTC and removing TOC from wastewater.

Degradation of tris(1,3-dichloro-2-propyl) phosphate (TDCPP) by ultraviolet activated hydrogen peroxide: Mechanisms, pathways and toxicity assessments

The ubiquity and ecotoxicity of tri (1,3-dichloro-2-propyl) phosphate (TDCPP) in aquatic environments make it essential to develop efficient related treatment techniques. The present research aims to systematically explore the mechanisms and toxicity changes of TDCPP degradation through UV-driven hydrogen peroxide process (UV/H2O2). The results revealed degradation efficiency of TDCPP attained 95 % with 0.5 mM H2O2, corresponding to a reaction rate constant (k) of 0.04919 min−1. Furthermore, three typical chlorinated OPEs (Cl-OPEs) were simultaneously degraded by the UV/H2O2 process, with different degradation efficiencies, according to the following order: TCEP<TDCPP<TCPP. The degradation efficiency was restricted under alkaline condition and the presence of humic acid (HA), nitrate (NO3–), chloride (Cl-), sulfate (SO42-), and dihydrogen phosphate (H2PO4-). A total of 12 intermediates were identified, which were generated through different pathways, including bond breaking, hydroxylation, and oxidation reactions. The Toxicity Estimation Software Tool (T.E.S.T) results demonstrated stronger mutagenicity and developmental toxicity of the TDCPP intermediates than parent compound. According to RNA sequencing results, UV/H2O2-based TDCPP degradation for 20 min and 60 min still had negative effects on Escherichia coli (E. coli). Indeed, the Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis results further suggested the stronger negative effect (e.g., damaging effects on the cell membrane, energy metabolism, and vitality) of the 20-min oxidation solution on E. coli, followed by those observed in without treatment and 60-min oxidation solution. Therefore, longer oxidation times are required in the UV/H2O2 process to decrease the toxicity of TDCPP.

Material compatibility of epoxies exposed to repeated low temperature vaporized hydrogen peroxide sterilization

ABSTRACT Through technological advancements, medical devices have evolved in their designs and have become more complex in both their design and materials of construction. Medical grade biocompatible epoxies are widely used in reusable medical devices. Choosing an epoxy that maintains its performance characteristics when subjected to repeated sterilization throughout the reusable medical device’s lifespan is a known challenge for medical device manufacturers. This study evaluated the material compatibility of seven cured 2-part and 1-part epoxies used in medical devices following exposure to 100 cycles in a low temperature vaporized hydrogen peroxide sterilizer. Six of the seven epoxies tested were found to be compatible with vaporized hydrogen peroxide sterilization based on qualitative, hardness and weight measurements conducted post exposure to 100 VHP cycles. The epoxies deemed to be compatible displayed no visual signs of physical defects, minimal reduction in hardness (≤2%) and total weight gain (≤2.9%). One of the epoxy samples did not maintain its texture and exhibited 17% loss in hardness post exposure to 100 VHP sterilization cycles and was found to be incompatible with the low temperature vaporized hydrogen peroxide process. This study verifies the need for material compatibility evaluations of epoxies prior to designing and developing a medical device while keeping in mind the application, lifecycle and intended use of medical devices.

Optimizing Micro/Nanobubble Ozonation: Unveiling Key Transition Points in Ozone Oxidation through Real-Time ORP Monitoring and Combined Ozone–Hydrogen Peroxide Process in Textile Wastewater Treatment

Optimizing Micro/Nanobubble Ozonation: Unveiling Key Transition Points in Ozone Oxidation through Real-Time ORP Monitoring and Combined Ozone–Hydrogen Peroxide Process in Textile Wastewater Treatment

Unveiling the potential of machine learning in cost-effective degradation of pharmaceutically active compounds: A stirred photo-reactor study

In this study, neural networks and support vector regression (SVR) were employed to predict the degradation over three pharmaceutically active compounds (PhACs): Ibuprofen (IBP), diclofenac (DCF), and caffeine (CAF) within a stirred reactor featuring a flotation cell with two non-concentric ultraviolet lamps. A total of 438 datapoints were collected from published works and distributed into 70% training and 30% test datasets while cross-validation was utilized to assess the training reliability. The models incorporated 15 input variables concerning reaction kinetics, molecular properties, hydrodynamic information, presence of radiation, and catalytic properties. It was observed that the Support Vector Regression (SVR) presented a poor performance as the ε hyperparameter ignored large error over low concentration levels. Meanwhile, the Artificial Neural Networks (ANN) model was able to provide rough estimations on the expected degradation of the pollutants without requiring information regarding reaction rate constants. The multi-objective optimization analysis suggested a leading role due to ozone kinetic for a rapid degradation of the contaminants and most of the results required intensification with hydrogen peroxide and Fenton process. Although both models were affected by accuracy limitations, this work provided a lightweight model to evaluate different Advanced Oxidation Processes (AOPs) by providing general information regarding the process operational conditions as well as know molecular and catalytic properties.

Tuning a green carboxymethyl cellulose-based pre-tanning agent via peroxide oxidation for high chrome exhaustion in leather industry

The low chrome uptake by collagen in the conventional tanning process leads to the pollution of the wastewater. Due to environmental concerns, leather scientists are already searching for innovative ways to produce pre-tanning agents as a high exhaustion chrome tanning auxiliary. Herein, a novel kind of pre-tanning agent is engineered by converting carboxymethyl cellulose (CMC) to oxidized carboxymethyl cellulose (OCMC) via the hydrogen peroxide process. FT-IR and carboxyl content analysis demonstrated the increase in carboxyl content after oxidation. After that, the obtained OCMC was utilized as a pre-tanning agent, resulting in a high exhaustion of chrome (92.76 %) which is 27.76 % more than conventional chrome tanning (65 %), and the amount of chrome in wastewater reduced to 7.24 %. The hydrothermal stability of wet-blue increased by increasing the uptake of chrome (Ts = 118 °C). The obtained crust leather represented excellent mechanical properties (Tensile strength: 305.68 kg/cm2; tear strength: 50 kg/cm) and desirable organoleptic properties. The environmental analysis signifies a significant step towards a cleaner and sustainable tanning process (COD = 1600, BOD5 = 560 mg/L) compared to the conventional chrome tanning process. Consequently, the obtained results offer a green pre-tanning agent to meet the requirements of the sustainable development of the leather industry.

CHARACTERIZATION OF LIGNIN DISSOLVED DURING ALKALINE SODIUM BOROHYDRIDE AND HYDROGEN PEROXIDE PRETREATMENTS OF SUGAR MAPLE (ACER SACCHARUM)

Sugar maple (Acer saccharum) wood chips were pretreated with aqueous sodium hydroxide, sodium borohydride, and hydrogen peroxide pretreatments, and the characterization (i.e., amount, molar masses, and molar mass distributions) of the lignin dissolved during the pretreatments was performed. Of the applied pretreatments, especially borohydride pretreatments were efficient in dissolving lignin from this feedstock, as 20% to 28% of the dissolved organics were found to consist of dissolved lignin, contributing to 3.4% to 9.0% of the initial wood lignin. Corresponding values for 2.5% and 5.0% alkaline peroxide pretreatments were from 5.9% to 9.2% dissolved lignin of the total dissolved organics and from 1.1% to 3.2% of the initial wood lignin. Additionally, determined molar masses and molar mass distributions indicated that borohydride pretreatments generally led to the formation of smaller-molar-mass lignin fragments when compared to reference pretreatments and to pretreatments conducted with alkaline peroxide process, indicating more efficient lignin degradation caused by borohydride addition. For example, Mn and Mw values of the analyzed reference effluents were 54%-62% and 66%-71% higher when compared to the corresponding borohydride effluents, respectively.

Degradation of chloroquine phosphate during UV/H2O2 process: Performance, kinetics, and degradation pathways

Residues of chloroquine phosphate (CQP) in the aquatic environment pose a potential hazard to aquatic organisms and human health. Herein, the degradation kinetics and pathways of CQP during ultraviolet/hydrogen peroxide (UV/H2O2) process were investigated. Results demonstrated that UV/H2O2 process exhibited the highest performance for CQP degradation compared to the single UV or H2O2 process. The second-order rate constants of CQP with hydroxyl radicals were determined as 8.9×109–1.2×1010 M–1 s–1 at pH 4.8–10.8. With the increase of H2O2 dosage from 0.2 to 3.0 mM, the degradation rate constant of CQP firstly improved from 0.0164 to 0.1267 min–1 and then slightly reduced to 0.1104 min–1 at 6.0 mM. The degradation efficiency of CQP by UV/H2O2 was significantly promoted at pH 4.8. Cl– and HCO3– showed the unobvious effects on the CQP degradation. Meanwhile, a kinetic model was established to simulate the evolution of CQP and various reactive species during UV/H2O2 process. The trend of predicted values of CQP degradation obtained from model simulation were well compared with experimental values. According to the identified intermediates of CQP degradation, the possible degradation pathways of CQP were proposed, which mainly involved N-deethylation, C–N bond cleavage, hydrogen abstraction, and N-oxidation. The aquatic toxicity of CQP degradation products was reduced relative to CQP, while the developmental and mutagenic toxicities of some intermediates were higher than CQP. Moreover, the economic consumption of UV/H2O2 treatment of CQP was determined under varied H2O2 concentrations. In general, UV/H2O2 process may constitute an effective option for treating CQP-contaminated water.

EFFECT OF 137CS ON FATTY ACID COMPOSITION IN COW`S MILK

Lipid composition of raw milk is a key factor determining the nutritional value and technological suitability of the milk. Monitoring the level of contamination of cow’s milk is often not available for farmers, living in the zone of radioactive contamination. 137Cs activity concentration was higher than permissible level of 100 Bq/kg in all the studied milk samples from all the experimental groups of animals from the studied settlements. The highest value of the 137Cs activity concentration of 600 Bk/kg in cow’s milk was found in Stare Selo village of Rokytne district. According to our study, local animals have partially adapted to the seasonal increase in background radiation, and the milk of these cows, in accordance with existing quality standards, is conditionally suitable for consumption. The only factor prohibiting the consumption of this milk is the level of cesium-137 contamination. An increase in the 137Cs activity concentration of more than 100 Bq/kg in cow’s milk causes a sharp decrease in the relative content of polyunsaturated fatty acids (mostly of omega-6 fatty acids) and changes in the omega-3/omega-6 ratio downward omega-3 relative content. Relative adaptation of the lactating cows to the contamination was revealed; however, metabolism of lipids in the mammary gland and the level of lipids secretion are found to be sensitive to the level of 137Cs contamination of milk. Thus, a violation of the secretory function of the mammary gland was revealed, in particular, metabolism of lipids with 18 carbon atoms in the chain. Relative content of linoleic acid immediately decreases by several times with the increasing the contamination level. Concentration of the stearic acid immediately exceeds the physiological limits at the value of 137Cs activity concentration in milk about 110–130 Bq/kg. It gradually increases with the increasing the 137Cs activity concentration up to 270–330 Bq/kg. And then it is being plateaued with the increasing the 137Cs activity concentration up to 600 Bq/kg. On the base of the study of effect of 137Cs on fatty acid ratio in cow’s milk, the C18-coefficient is being proposed to be used as the parameter of damage to the mammary gland of cows in response to a high level of 137Cs contamination, which is calculated as follows: C18c = (C18:0–C18:2)/100). Determination of the C18-coefficient indicates the dose-dependent effect of the 137Cs contamination on lipid metabolism in the mammary gland and catabolism of polyunsaturated fatty acids, particularly linoleic acid. Duration of the affecting contamination is obviously decisive factor of damage effect to the mammary gland, defining the level of biochemical transformations and initiating of peroxide processes.

Controllable Pyridine N-Oxidation-Nucleophilic Dechlorination Process for Enhanced Dechlorination of Chloropyridines: The Cooperation of HCO4- and HO2.

Dechlorination of chloropyridines can eliminate their detrimental environmental effects. However, traditional dechlorination technology cannot efficiently break the C-Cl bond of chloropyridines, which is restricted by the uncontrollable nonselective species. Hence, we propose the carbonate species-activated hydrogen peroxide (carbonate species/H2O2) process wherein the selective oxidant (peroxymonocarbonate ion, HCO4-) and selective reductant (hydroperoxide anion, HO2-) controllably coexist by manipulation of reaction pH. Taking 2-chloropyridine (Cl-Py) as an example, HCO4- first induces Cl-Py into pyridine N-oxidation intermediates, which then suffer from the nucleophilic dechlorination by HO2-. The obtained dechlorination efficiencies in the carbonate species/H2O2 process (32.5-84.5%) based on the cooperation of HCO4- and HO2- are significantly higher than those in the HO2--mediated sodium hydroxide/hydrogen peroxide process (0-43.8%). Theoretical calculations confirm that pyridine N-oxidation of Cl-Py can effectively lower the energy barrier of the dechlorination process. Moreover, the carbonate species/H2O2 process exhibits superior anti-interference performance and low electric energy consumption. Furthermore, Cl-Py is completely detoxified via the carbonate species/H2O2 process. More importantly, the carbonate species/H2O2 process is applicable for efficient dehalogenation of halogenated pyridines and pyrazines. This work offers a simple and useful strategy to enhance the dehalogenation efficiency of halogenated organics and sheds new insights into the application of the carbonate species/H2O2 process in practical environmental remediation.

Investigation of Treatability of Automotive Industry Wastewaters by Coagulation-Flocculation, Fenton and UV/H2O2

In the automotive industry, painting operations have emerged as a major source of environmental concerns. In this study, the treatability of wastewater obtained from the automotive industry painting process was investigated by using coagulation-flocculation, ultraviolet/hydrogen peroxide (UV/H2O2), and Fenton processes. The effects of pH, coagulant, and anionic polymer doses were examined for three different coagulants in the coagulation-flocculation process. Optimal conditions were determined based on chemical oxygen demand (COD) and turbidity removal efficiency. As a result of the study, the optimum conditions for the coagulant identified as ferric chloride, which achieved the highest COD removal of 49.6% and turbidity removal of 74.4%, were determined as pH 8, coagulant dose of 400 mg L-1, and anionic polymer dose of 1 mg L-1. In the second stage of the study, Fenton and UV/H2O2 processes were applied to the effluent of the coagulation-flocculation process to increase the removal efficiency. When the results were evaluated, it was observed that the maximum COD removal efficiency of 63.4% was attained under the conditions of pH 3 and 400 mg L-1 H2O2 concentration applied in the UV/H2O2 process. However, in the Fenton process, a maximum COD removal efficiency of only 51% was achieved. From this study, it can be concluded that the UV/ H2O2 process applied after coagulation-flocculation increases the removal efficiency and can be an alternative and effective treatment process for wastewater from the automotive painting process.

Selective oxygen reduction reaction: mechanism understanding, catalyst design and practical application.

The oxygen reduction reaction (ORR) is a key component for many clean energy technologies and other industrial processes. However, the low selectivity and the sluggish reaction kinetics of ORR catalysts have hampered the energy conversion efficiency and real application of these new technologies mentioned before. Recently, tremendous efforts have been made in mechanism understanding, electrocatalyst development and system design. Here, a comprehensive and critical review is provided to present the recent advances in the field of the electrocatalytic ORR. The two-electron and four-electron transfer catalytic mechanisms and key evaluation parameters of the ORR are discussed first. Then, the up-to-date synthetic strategies and in situ characterization techniques for ORR electrocatalysts are systematically summarized. Lastly, a brief overview of various renewable energy conversion devices and systems involving the ORR, including fuel cells, metal-air batteries, production of hydrogen peroxide and other chemical synthesis processes, along with some challenges and opportunities, is presented.

Elucidating the performance of UV-based photochemical processes for the removal of trace organic contaminants: Degradation and toxicity evaluation

In this study, the performance of standalone ultraviolet (UV) photolysis and UV-based advanced oxidation processes (AOPs), namely, UV/hydrogen peroxide, UV/chlorine, UV/persulphate, and UV/permonosulphate, were investigated for the degradation of 31 trace organic contaminants (TrOCs). Under the tested conditions, standalone UV photolysis did not achieve effective removal of TrOCs. To improve the degradation efficiency of UV photolysis, four different oxidants were added individually to the test solution. The effect of these oxidants in the absence of UV irradiation was also explored and only chlorine showed promising degradation of some contaminants. During the chlorination of 31 investigated TrOCs, only six demonstrated greater than 50% degradation. The combined UV-based AOPs demonstrated much improved degradation (ranging from 65 to 100%) depending on TrOC-structure and oxidant concentration. The UV/hydrogen peroxide process showed similar degradation of TrOCs, irrespective of the functional groups (i.e., electron withdrawing groups, EWGs and electron donating groups, EDGs) present in their structures. Conversely, the UV/sulphate and UV/chlorine based processes achieved better degradation of the TrOCs with EDGs in their structures. TrOCs degradation improved up to 40% when oxidants concentrations were increased from 0.1 to 1 mM, and further increasing the concentration to 2 mM did not improve degradation. Toxicity evaluation using bioluminescence test (BLT assay) demonstrated that except for UV/hydrogen peroxide, all UV-based AOPs increased the toxicity of the treated effluent, indicating generation of toxic by-products. This study elucidates the performance of four different UV-based AOPs for the removal of commonly detected diverse TrOCs for the first time.

Evaluation of combined efficiency of conventional coagulation-flocculation process with advanced oxidation process (sulfate-hydroxyl radical) in leachate treatment

This study evaluated a novel municipal solid waste leachate (MSWL) treatment system called the Batch flow leachate treatment system (BFLTS). This process uses a combination of coagulation/flocculation (C-F), advanced oxidation (sulfate-hydroxyl radical), and extended aeration of activated sludge (EAAS) to treat MSWL. The results indicated that the primary treatment phase using coagulation/flocculation with 0.8 g L&lt;sup&gt;-1&lt;/sup&gt; FeCl&lt;sub&gt;3&lt;/sub&gt; at pH 6 achieved 67% turbidity and 63% chemical oxygen demand (COD) reduction. The secondary treatment phase with the presence of both K&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; peroxides was more efficient than single peroxide processes. While PS-based or H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;-based single peroxide processes are less effective (UV-PS 65.7%, UV-H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; 43.2%, Heat-PS 58.6%, Heat-H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; 34.5%, and Heat-PS/H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; 74.8%). The UV-PS/H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; system achieved the highest COD removal rate of 89.4%. In the third treatment phase, the efficient removal of COD and Biochemical oxygen demand (BOD) under optimal operating conditions was 87.3% and 94.7% respectively. Overall, the BFLTS treatment system has demonstrated high efficiency in removing COD, BOD, TSS, Turbidity, TKN, and Heavy metals by 99%, 98%, 97%, 89%, 86%, and 98%, respectively. This hybrid process has potential for reducing organic load in MSWL and can be used for various leachates.

Tertiary/quaternary treatment of urban wastewater by UV/H2O2 or ozonation: Microplastics may affect removal of E. coli and contaminants of emerging concern

The aim of this study was to investigate the interference of polyethylene microplastics (MPs) on ultraviolet irradiation/hydrogen peroxide (UV/H2O2) and ozonation processes in the inactivation of E. coli bacteria (tertiary treatment) and removal of contaminants of emerging concern (CECs) (quaternary treatment) from simulated and real secondary treated urban wastewater. Three pharmaceuticals were investigated as model CECs, namely carbamazepine, sulfamethoxazole and trimethoprim. Experimental results showed that disinfection efficiency of UV/H2O2 treatment decreased (2.4, 1.8 and 1.3 log reductions of E. coli, initial H2O2 dose of 30 mg/L, 2.5 min treatment) as the initial concentration of MPs was increased (0.25, 0.5 and 1.0 g/L, respectively). Similarly, an increase in MPs concentration (0.25, 0.5 and 1.0 g/L) reduced the inactivation (4.7, 4.1 and 3.7 log reductions) of the target bacteria after 60 min of ozonation treatment. Although the disinfection efficiency of both treatment processes was negatively affected by the presence of MPs, UV/H2O2 was more effective than the ozonation, despite ozonation being investigated at high doses to better discriminate the effect of MPs. Noteworthy, CECs degradation by UV/H2O2 under realistic operating conditions was affected to some extent by MPs, while a lower effect was observed for ozonation, at not realistic ozone dose.

Efficient Removal of Perfluorooctanoic Acid by UV-Based Peroxide and Persulfate Advanced Oxidation Processes

Perfluorooctanoic acid (PFOA) challenges traditional methods of aquatic treatment and recycling from recalcitrant organic compounds, which ubiquitously persist in the environment, mainly water bodies, and cause various adverse effects on humans and the environment. Conventional water treatment technologies are proven inefficient and must focus on advanced oxidation processes. This study conducted treatability studies for removing PFOA by direct photolysis, UV/peroxide, and UV/persulfate oxidation using a lab-scale reactor. The experiment was performed with an initial concentration of 20 mg/L for 120 min for a 500 mL of sample. The oxidant dosage and pH were optimized based on the mineralization efficiency. An efficient method for PFOA degradation is based on its percentage reduction in concentration, mineralization efficiency, and reaction kinetics study. It was found that all three processes were adequate for mineralizing PFOA. Among them, UV/persulfate was more effective in mineralizing PFOA. The total organic carbon removal percentages using direct photolysis, UV/persulfate, and UV/peroxide treatments were 49%, 80%, and 66%, respectively. The pseudofirst-order kinetics for these three were 0.160, 0.489, and 0.349 h−1, respectively.

Selective abatement of electron-rich organic contaminants by trace complexed Mn(II)-catalyzed periodate via high-valent manganese–oxo species

Mn(II) is among the most efficient catalysts for the periodate (PI)-based oxidation process. In-situ formed colloidal MnO2 simultaneously serves as the catalyst and oxidant during the degradation of organic contaminants by PI. Here, it is revealed that the complexation of Mn(II) by ethylene diamine tetraacetic acid (EDTA) further enhances the performance of PI-based oxidation in the selective degradation of organic contaminants. As evidenced by methyl phenyl sulfoxide probing, 18O-isotope labeling, and mass spectroscopy, EDTA complexation modulates the reaction pathway between Mn(II) and PI, triggering the generation of high-valent manganese–oxo (MnV–oxo) as the dominant reactive species. PI mediates the single-electron oxidation of Mn(II) to Mn(III), which is stabilized by EDTA complexation and then further oxidized by PI via the oxygen-atom transfer step, ultimately producing the MnV–oxo species. Ligands analogous to EDTA, namely, [S,S]-ethylenediaminedisuccinic acid and L-glutamic acid N,N-diacetic acid, also enhances the Mn(II)/PI process and favors MnV–oxo as the dominant species. This study demonstrates that functional ligands can tune the efficiency and reaction pathways of Mn(II)-catalyzed peroxide and peroxyacid-based oxidation processes.

Ecological and toxicological features of the effect of stable cesium on striated muscle tissue (myocardium and skeletal muscles) of mammals

Recently, the risks of radiation danger have significantly increased. This is connected with the start of a full-scale war against Ukraine and the seizure of the Zaporizhzhya NPP by the Russian Federation, which has the second most powerful arsenal of nuclear weapons in the world. The majority of studies devoted to the effect of radioactive radiation on the human body and animals absolutely do not take into account the ecotoxic effect of the carrier and a chemical element. At the same time, the body does not distinguish between radioactive and non-radioactive isotopes of chemical elements and interacts with them during exchange processes. The aim of the work was to study the influence of stable cesium on the microscopic structure of striated muscle tissue, both skeletal and cardiac ones. The results of our research revealed that intensive accumulation of cesium for 24 days occurred in all the examined organs and tissues. In fact, the most intensive accumulative process appeared to be in the heart by 214.9 times and by 695.3 times with skeletal muscles, with a simultaneous decrease in potassium content by 19.2% and 29.1%, respectively, compared to intact rats. We can talk about the presence of two mechanisms of action of cesium on tissues, including striated muscles: as an antagonist of potassium, which concerns the transport system of the latter and as a toxic element that initiates peroxide processes with subsequent modification of membranes and their potassium channels. Functional disturbances in the work of potassium channels of excitable tissues in the repolarization phase occur in the conditions of an increase in intracellular cesium in striated muscles. These disorders can proceed according to the type of acquired "potassium" channelopathies, which in the myocardium can manifest in the form of rhythm disorders, prolonged QT syndrome, etc. This leads to the appearance of significant violations of the histological structure of the examined tissues. Cesium has pronounced damaging effects on both skeletal and cardiac striated muscle tissue, with morphological changes in skeletal and cardiac striated muscle tissue being generally similar. Dystrophic changes in the nuclei and cytoplasm of cardiomyocytes and striated muscles, signs of impaired blood circulation in the microcirculatory channel with the formation of vascular wall edema, destruction of endothelial cells, various types of hemorrhages and lymphohistiocytic infiltration of the stroma of fibers are the consequences of the toxic effect of cesium on tissues. Thus, the results of changes in the histological structure of striated muscles under the action of cesium chloride obtained by us indicate a fairly high cytocidal activity of stable cesium.

Клинико-лабораторные исследования в комплексной диагностике и лечении увеитов у детей

This work is devoted to the analysis of the effectiveness of new clinical and laboratory studies and their possible application in treatment of uveitis in children. The paper assesses the study of the glutathione-reducing system as a factor in the vulnerability of eye tissues to the effects of free radicals and peroxidation products during inflammation. The dependence of the clinical picture of uveitis and the frequency of detection of eye tissue antigens in the blood was analyzed to assess the localization and stage of the pathological process, which will undoubtedly determine the tactics of the therapy. Evaluation of the main indicators of the activity of peroxidation processes in uveitis is proposed to be carried out according to the original method for determining the functional activity of polymorphonuclear leukocytes (PNLs). It was proved that there is a close relationship between the level of PNLs activity, the level of intensity of peroxide processes and the ophthalmic picture of uveitis. Based on the results obtained in the following work, the use of pharmaceutical antioxidants, both traditional and those known drugs in which antioxidant properties were discovered for the first time, was proposed. This paper offers a concept of the development of toxic-allergic uveitis, including successive stages of the formation of immune complexes, inflammation, an increase in the functional activity of PMNs, their chemotaxis into the inflammation zone, infiltration through the capillary walls in the eye tissue, which leads to an avalanche-like increase in the level of oxidants, depletion of endogenous reserves of antioxidants, damage to cell membranes. Understanding these processes serves as an explication for developing optimal treatment regimens for uveitis and other inflammatory ophthalmpathology. Keywords: uveitis, retinal antigens, glutathione system, antioxidants, polymorphonuclear leukocytes, peroxidation, reactive oxygen species