Hydrogen Peroxide In Alkaline Solution Research Articles

Trimetallic Sulfide Hollow Superstructures with Engineered d-Band Center for Oxygen Reduction to Hydrogen Peroxide in Alkaline Solution.

High‐performance transition metal chalcogenides (TMCs) as electrocatalysts for two‐electron oxygen reduction reaction (2e‐ORR) in alkaline medium are promising for hydrogen peroxide (H2O2) production, but their synthesis remains challenging. In this work, a titanium‐doped zinc–cobalt sulfide hollow superstructure (Ti–ZnCoS HSS) is rationally designed as an efficient electrocatalyst for H2O2 electrosynthesis. Synthesized by using hybrid metal–organic frameworks (MOFs) as precursors after sulfidation treatment, the resultant Ti–ZnCoS HSS exhibits a hollow‐on‐hollow superstructure with small nanocages assembled around a large cake‐like cavity. Both experimental and simulation results demonstrate that the polymetallic composition tailors the d‐band center and binding energy with oxygen species. Moreover, the hollow superstructure provides abundant active sites and promotes mass and electron transfer. The synergistic d‐band center and superstructure engineering at both atomic and nanoscale levels lead to the remarkable 2e‐ORR performance of Ti–ZnCoS HSS with a high selectivity of 98%, activity (potential at 1 mA cm−2 of 0.774 V vs reversible hydrogen electrode (RHE)), a H2O2 production rate of 675 mmol h–1 gcat –1, and long‐term stability in alkaline condition, among the best 2e‐ORR electrocatalysts reported to date. This strategy paves the way toward the rational design of polymetallic TMCs as advanced 2e‐ORR catalysts.

Roughness and Uniformity Control during Wet Etching of Molybdenum

In this work the wet etching of molybdenum thin films was investigated for applications requiring controlled recess without roughening or pattern loading. First, continuous etching of Mo in alkaline and oxidative peroxide solutions was studied. Then, additives like glycine and diethylenetriamine were used and their effect on etch rate and roughness was assessed. Finally, we evaluated if the requirements for a stepwise etching approach for Mo recess using peroxide or ozonated water as the oxidizing step and ammonia as the oxide dissolution agent were met.

Kovid 19 - intrapulmonalni alkalni hidrogen-peroksid može trenutno da poveća oksigenaciju krvi

It has been shown that the new coronavirus infection is life-threatening for patients not because of the COVID-19 virus, but because of the complications it causes. The most dangerous complication of this disease is the airway obstruction syndrome, which occurs with atypical pneumonia. Blockage of the airways occurs due to the accumulation of excessively large amounts of mucus and pus in them and swelling of the lung tissue, so ventilation of the lungs with air becomes almost impossible. The sad outcome of respiratory obstruction is hypoxia and hypoxic brain damage. Under these conditions, extracorporeal membrane oxygenation remains the only known way to increase blood oxygenation. However, in 2021, it was shown that intra-pulmonary administration of a warm alkaline solution of hydrogen peroxide immediately turns mucus and pus into oxygen foam and increases blood oxygen saturation. The proposed technology is a new variant of emergency blood oxygenation in severe suffocation caused by blockage of the respiratory tract with mucus, pus and blood.

Hydrogen peroxide discolors blood in the cavity of the hematoma under the nail and in the skin over the bruise

Purpose. Modern medical standards do not contain information about the urgent bleaching of nail hematomas and bruises. The aim of this work is developing of new ways and means for blood bleaching of the bruising and subungual hematomas for its immediate discoloration. Materials and methods. The peculiarities of hydrogen peroxide effect on blood color alteration in different environment have been studied in laboratory, by experiment and in clinical conditions. We studied the peroxide effect on liquid and dry venous blood in a Petri dishes, in bloody gauze bandages, on the surface of the skin, in hematoma under the nail in humans and in the skin over the bruise created by intradermal injection of pig blood. The studies take into account the role of local interaction such factors as the duration of interaction, the concentration of ingredients, local temperature, the value of alkaline and osmotic activity of the studied solutions. The results were recorded by color photo and video. Results. In laboratory and experimental conditions the red and blue blood as well as red, brown and/or blue stained tissues were shown to be urgently bleached by alkaline solutions of hydrogen peroxide. Hemoglobin was found to be the «dye» of blood-stained tissues. We listed the inventions to the intradermal bruising discoloration, subungual hematomas, and fresh and dried blood. The main ingredients of the inventions for intradermal and subungual hematomas bleaching are reported. The essence of the invented methods of skin and nail hematomas discoloration is presented. Conclusion. The alkaline solution of hydrogen peroxide can be used for emergency discoloration subungual hematoma, the skin in the area of bruise and the bandage stained with blood.

THE SOAKING EFFECT OF 100% SMALL WHITE GINGER EXTRACT ON THE VALUE OF THE FLEXURAL STRENGTH OF ACRYLIC BASE (Flexural Strength Value of Acrylic Base Using Acrylic Resin Heat Cured Type)

Background: The denture base material that is widely used is heat cured acrylic resin. One of mechanical properties of acrylic resin that must be considered in the selection of the basic denture material is flexural strength. Flexural strength is needed, among others, to resist the chewing power that must be received by dentures. The commonly used denture cleanser is Alkaline peroxide. 100% small white ginger extract can be used as natural denture cleanser. Objective: This study aimed to compare the flexural strength of heat cured acrylic base which in soaked 100% small white ginger extract with Alkaline peroxide solution as artificial denture cleanser. Method: This study was a pure laboratory experimental study with post test only with control group design, using simple random sampling. The sample was rectangular with a size of 65x10x2,5 mm. The number of samples used was 24 heat cured resin acrylic which was divided into 3 immersion groups, 100% small ginger extract, Alkaline peroxide, and aquades. The immersion carried out for 3 days 19 hours 25 minutes, obtained from 5 minutes denture cleanser presentation every day for 3 years. Flexural strength was tested using a Universal Testing Machine 3 Point Bending. Result: The everage flexural strength value of heat cured acrylic resin after soaked in 100% small white ginger extract was 70,98, in Alkaline peroxide 87,37, and 91,05 in aquades. The data was annalyzed using parametric One Way ANOVA test and Post Hoc Bonferroni test. Conclusion: The flexural strength of heat cured acrylic resin that soaked in 100% small white ginger extract is smaller than Alkaline peroxide after immersed for 3 days 19 hours 25 minutes.

Hemicellulose transportation from different tissues of corn stalk to alkaline hydrogen peroxide solution

During hemicellulose alkali extraction from corn stalk (CS), focus has historically been on describing the effect of some key process parameters whereas less attention has been paid to the composition and structure differences of the CS raw material. This paper aimed to analyze the composition and structure of the different parts of CS and provide models of hemicellulose transportation. The results showed that the dissolution of hemicellulose was mainly influenced by not only the alkali-soluble hemicellulose content but also the density of tissue. In addition, the modelling results strongly reflected that all the dissolution processes of hemicellulose from the three parts belonged to physical mass transfer-dominated process.

Studies on the suitability of oxidizing agents for discolouring lime and poplar wood in the first stage of transparent wood forming process

Studies on the suitability of oxidizing agents for discolouring lime and poplar wood in the first stage of transparent wood forming process. Series of lime and poplar wood samples were prepared and subjected to oxidising agent in order to decolourise wood in bulk. Sodium chlorite solution in the environment of diluted acetic acid and alkaline hydrogen peroxide solution were used as different treating agents, followed by intense rinsing in water and drying the samples. The effect of wood delignification conditions such as time of treatment and reagent used was investigated. Changes in mass and dimensions of the samples were measured, and thus density changes were calculated. Colour changes were measured with colorimeter in CIE Lab colour space. In the case of lime wood swelling of the samples was observed at the first stage, along with mass loss, leading to density decrease by 10 % after 20 h exposure. In the case of poplar wood, shrinking of the samples was observed, but due to severe mass loss, final density was similar to lime wood. Colour changes correlated mainly with lightness parameter of the samples. Significant colour differences were found even at the shortest time of treatment.

Electrogenerated alkaline hydrogen peroxide for rice straw pretreatment to enhance enzymatic hydrolysis

In this work, alkaline hydrogen peroxide (AHP) solution with 1 wt% H2O2 was electrogenerated by oxygen reduction with a current efficiency of 75.2% in a home-made gas diffusion electrode-based electrochemical cell and used for rice straw pretreatment (0.1 g H2O2/g rice straw, 10% (w/v) biomass loading, 55 °C, 2 h). Results showed that the AHP pretreatment removed 97.56% of the initial lignin, 85.75% of the initial hemicellulose, and only 0.56% of the initial cellulose, and the specific surface area and porosity of the AHP pretreated rice straw (AHP-RS) were greatly increased. Saccharification results showed that after 48 h of enzymatic hydrolysis AHP-RS achieved a 3.2-fold increase in reducing sugar concentration compared to the untreated rice straw (5.81 and 1.81 g L−1), highlighting the potential use of this AHP solution for lignocellulose pretreatment.

Studies on delignification and inhibitory enzyme kinetics of alkaline peroxide pre-treated pine and deodar saw dust

Delignification of lignocellulosic biomass by alkaline peroxide pre-treatment is a preliminary important step for an overall biomass fractionation process. In the present work, saw dusts are pre-treated by aqueous alkaline peroxide solution under different temperatures over a predetermined time. It is seen that Combined Pre-treatment (CP) removes a substantially higher quantity of lignin from biomass under a particular temperature. At elevated temperatures, the extent of delignification is observed much better. The % removal is: [PR: 19.35%(30 °C):25.26%(50 °C):33.30%(100 °C)]; [CD:14.64%(30 °C):23.64%(50 °C): 28.83%(100 °C)]. Batch kinetics is investigated with certain models and corresponding parameters are estimated. As pre-treatment severity is strongly correlated to the pre-treatment temperature, increased value of “potential degree of delignification” is observed at escalated temperatures. Kinetics of enzymatic hydrolysis of delignified biomass shows decreased product inhibition with increased substrate concentration under a particular enzyme loading. Starting with a combination of 50 g/L substrate concentration with an enzyme loading of 13.23 g/L, an optimum concentration of 17.2 g/L and 21.19 g/L of glucose are produced from Pinus roxburghii and Cedrus deodara respectively. Experimental data fit quite well with the competitive inhibition kinetics based theoretical models with r2 ≥0.95. It is inferred that enzymes are competitively inhibited by glucose.

Polarography as a technique of choice for the evaluation of total antioxidant activity: The case study of selected Coprinus Comatus extracts and quinic acid, their antidiabetic ingredient

This study was focused on in vitro screening of the total antioxidant activity of the selected extracts of the mushroom Coprinus comatus and quinic acid, one of their antidiabetic ingredients, by an uncommon electrochemical assay. Indeed, direct current (DC) polarographic HydroxoPerhydroxo Mercury(II) Complex (HPMC) assay based on decrease of anodic limiting current originating from HPMC formation in alkaline solutions of hydrogen peroxide at potential of mercury dissolution, observed upon gradual addition of antioxidants, was applied herein for the estimation of the natural products' antioxidativity. Quinic acid was found to exhibit most promising antioxidant potential (4.0 ± 0.2%µL−1) being ≈ 2-fold more active than the screened C. comatus extract samples. Actually, such a finding puts some light on the antioxidativity of cyclic polyols, well understimated class of organic compounds, compared to aromatic (poly)phenolics. As a low cost, easy-to handle and accurate this polarographic assay may be thoroughly recommended for much broader use.

Promoting the material properties of xylan-type hemicelluloses from the extraction step

Using originally isolated xylan-type hemicelluloses for material application suffers from poor mechanical properties including low tensile strength and brittleness. The subsequent chemical modifications of hemicelluloses are facing the problems of high costs and toxic chemicals. Consequently, this study tried to investigate the factors affecting the film-forming properties of the originally isolated xylan-hemicelluloses and promoting their material properties from the extraction step. Two different extraction methods, a one-step alkali or alkaline peroxide solution method and a two-step alkali extraction-delignification method were used to extract the hemicellulose with different chemical structures from sugarcane bagasse. For the two-step alkali extraction-delignification method, hemicelluloses were first extracted by alkali solution and then delignified by dioxane/water, hydrogen peroxide solution or sodium hypochlorite solution. The lignin contents of all the extracted hemicelluloses ranged from 1.6%–9.5%, of which the lowest value was obtained through delignification by sodium hypochlorite. The number average molecular weight ranged from 8200 to 26800, while the xylan/arabinan ratio ranged from 5.0 to 9.1. The hemicelluloses were characterized and processed into films. Tensile strength of films could be considerably improved up to ˜52% when using sodium hypochlorite solution as the delignification agents and the lignin content was greatly reduced for the hemicellulose fraction. Statistical models were generated between film mechanical properties and hemicellulose structural characteristics. The models predicted that hemicellulose with higher molecular weight, more linear structure and lower lignin content would result in better mechanical properties.

Effect of denture cleansers with and without fatigue stress on retention of locator attachments: in-vitro study

Background To evaluate the effect of denture cleansers with and without fatigue stress on the retention of the locator attachments. Materials and methods Three dummy implants of length (13 mm) and a diameter of 4.2 mm with their locator abutments were embedded into three acrylic resin blocks. Seventy pink locator attachments were divided into three groups: 10 for group I, 30 for each group II and group III. Group I exposed to 600 cycles of insertion and removal equivalent to 6 months use, group II and group III was subdivided into three subgroups, A, B, C according to the type of cleaner which was soaked in water, chlorhexidine gluconate 2% and alkaline peroxide solution for a period equivalent to 6 months. Group III was soaked in water, chlorhexidine gluconate 2% and alkaline peroxide solution, then exposed to 600 cycles of insertion and removal. The pink locator was tested for load to dislodgment on universal testing machine with a load cell of 5 kN at a crosshead speed of two in/min. Retention of locator attachments were statistically analyzed using Mann–Whitney test. Difference of mean values between more than two groups was tested by Friedman χ2-test. Results Group I: The retention of pink locator attachments was significantly decreased after 600 cycles of insertion and removal P = 0.005. Group II: The retentive value for attachment soaked in chlorhexidine gluconate 2% and that soaked in alkaline peroxide solution was significantly lower than that soaked in water (P = 0.001). Group III: the locator soaked in water and chlorhexidine gluconate 2% and alkaline peroxide solution was significantly affected after 600 cycles of insertion and removal. Conclusion Chlorhexidine gluconate 2% and alkaline peroxide solution has significant decrease the retention of pink locator attachment. Fatigue has significant effect on the retention of locator attachment either with or without the use of denture cleansers.

Image processing as a tool for evaluating denture adhesives removal techniques

ABSTRACTDenture adhesives are widely used, but patients express difficulty in removing it. Image processing was already using to evaluate the effectiveness of disinfection treatments. The objective of the present study is to evaluate, under image processing, the adhesive removal protocols recommended by the adhesive manufacturers. Thirty pink acrylic discs were made, and denture adhesives were applied to their outer surface. Afterwards, the adhesive was immersed in a green food-colouring agent for 30 s. The total surface area and pigmented areas were measured using an image processing software (Image Tool 3.0). After each measurement, the adhesive removal protocols were performed. Samples were divided into two groups. In group 1 discs were brushed with a denture brush and water, with three longitudinal movements. In group 2 the discs were submerged in water with a denture cleansing tablet for 3 min and brushed. Statistical analyses were performed (p = 0.05). In our study, water brushing provided less effective results. The combination of immersion in an alkaline peroxide solution followed by brushing, despite continuing to provide low efficacy, presents much better results. Image processing is a valid tool and an objective means to measure the efficacy of different techniques for dentures.

Valorization of Lignocellulosic Waste (Crotalaria juncea) Using Alkaline Peroxide Pretreatment under Different Process Conditions: An Optimization Study on Separation of Lignin, Cellulose, and Hemicellulose

ABSTRACTLignocellulose materials, essentially consisting of lignin, cellulose and hemicelluloses, are abundant sources of fermentable sugars. The bast fiber of Crotalaria juncea (Sunn hemp), a native cover crop of India, was used as feedstock for this study. The primary objective of this study was to add value to the waste C. juncea bast fiber. The same was achieved by pretreating the waste fiber using alkaline peroxide solution at various process conditions. The optimal process condition for alkaline peroxide pretreatment was identified for the fiber to pretreatment solution (S/S) ratio of 1/40 at 50°C for 5h with respect to all response variables (lignin removal, hemicellulose recovery, recovery of solid pretreated material, and crystallinity of lignocellulose). Three-way ANOVA results revealed that S/S ratio had no significant effect; whereas, both temperature and time, and the combination of parameters, exhibited significant effect on response variables. The characteristic peaks associated with lignin and cellulose demonstrated a higher amount of lignin removal and increased cellulose content with elevated treatment time. Autoclave assisted pretreatment proved to be inefficient due to removal of lower amount of lignin in addition to higher hemicellulose degradation. On the other hand, pretreatment using ultrasound was found to be most effective in removing lignin, liberating hemicelluloses along with diminition in cellulose crystallinity.

Modified Method for Trapping and Analyzing 15N in NO Released from Soils.

15N isotope tracing is an effective and direct approach to investigate sources of nitric oxide (NO) formed in soils. However, NO is highly reactive and rapidly converted to nitrogen dioxide (NO2) in the presence of ozone, making it impossible to directly measure 15N in NO. Various wet-chemical methods for conversion of NO to nitrite (NO2-) and nitrate (NO3-) have been proposed for 15N analysis in high-concentration NO sources, such as combustion processes. In contrast, NO concentrations in the soil surface-near air are usually small (ppbv-range), posing major challenges to conversion efficiency and blank correction. Here, we present a modified method in which NO is oxidized quantitatively to NO2 by chromium trioxide (CrO3), before conversion to NO2- and NO3- in an alkaline hydrogen peroxide (H2O2) solution. A denitrifier method was used to reduce NO2- and NO3- in the trapping solution quantitatively to nitrous oxide (N2O) for subsequent 15N analysis. NO trapping efficiencies of >85% were obtained with 50 ppb NO in a 0.5 L min-1 air stream bubbling through a solution of 1.2 M H2O2 and 0.5 M NaOH. In a laboratory test with distinct 15NO abundances, the overall precision was 0.29‰ (δ-values) for natural abundance NO and 0.13 atom % for labeled NO, suggesting that our method can be used for both natural abundance studies and 15N labeling experiments. In a soil incubation experiment with 15NH4NO3, NH415NO3, or Na15NO2 amendments, we found distinct 15N abundances in NO, indicating that our method is well suited to investigate NO sources in soils.

Chemical Methods for Cleaning Conventional Dentures: What is the Best Antimicrobial Option? An In Vitro Study.

To investigate the antimicrobial efficacy of different chemical agents used for denture cleaning. Biofilm samples collected from 10 removable dentures were subjected to 10 disinfection protocols: distilled water for 30 min (negative control); 1% sodium hypochlorite for 10 min (positive control); diluted sodium hypochlorite for 10 min; vinegar for 20 min; 0.2% peracetic acid for 5 min; alkaline peroxide solution for 5 min; alkaline peroxide solution for 30 min; 0.12% chlorhexidine digluconate for 10 min; 0.05% sodium salicylate solution for 10 min; and enzymatic detergent for 2 min. Each of the samples was plated on petri dishes with Mueller-Hinton agar. The numbers of microbial colonies after 48 h at 37°C were compared using the Kruskal-Wallis and Dunn's tests (α = 0.05). Diluted sodium hypochlorite, vinegar, and chlorhexidine digluconate inhibited bacterial growth, with an effect similar to that of 1% sodium hypochlorite. The 0.2% peracetic acid and 0.05% sodium salicylate solutions were ineffective against bacterial growth, while enzymatic detergent and alkaline peroxide achieved an intermediate effect. Diluted sodium hypochlorite, vinegar, and chlorhexidine digluconate can be considered adequate products for cleaning dentures due to their potential for inhibiting bacterial growth, similar to 1% sodium hypochlorite. However, the effect of these chemical agents on acrylic resin (polymethylmethacrylate) denture base materials needs to be examined to provide complete information about their clinical indication.

COLOR CHANGES COMPARISON OF HEAT CURED TYPE ACRYLIC RESIN IN IMMERSION OF ALKALINE PEROXIDES SOLUTION AND CELERY EXTRACT (APIUM GRAVEOLENS L.) 75

ABSTRACK Background: Heat cured-type acrylic resin is the most widely used as denture base. denture base that is less clean may result in the accumulation of microorganisms. The chemical denture cleanser solution such as alkaline peroxide and 75% celery extract are able to clean and inhibits the growth of fungi and bacteria. The disadvantage of acrylic resin is water absorbing includes denture cleanser solution that may result in color change of resin. Purpose: The study is aim at measuring the color change differences of heat cured-type acrylic resin in immersion of alkaline peroxide solution and 75% celery extract (Apium graveolens L.) as denture cleanser for 5 days and 15 days. Method: The study was a true experimental research with control group design pre-test and post-test, using sample of 2mm thickness and 15mm diameters based on ADA specification no 17. Total samples were 36, divided into 6 treatment groups that is immersed in alkalin peroxide solution, 75% celery extract and aquadest for 5 and 15 days. The color change was measured using tools spectrometer,101 photo detector and microvolt digital. The statistical test was using One-way ANOVA and Post Hoc Bonferroni with <0.05 significance. Result: There is significance differences of color change acrylic resin in immersion of alkaline peroxide solution and 75% celery extract for 5 days and 15 days. Mean value of color change alkalin peroxide solution (0,48mv), aquadest (0,33mv) and celery extract 75% (1,36mv) for 5 days, alkaline peroxide solution (0,50mv), aquadest (0,39mv) and 75% celery extract (1,00mv) for 15 days. Conclusion: The immersion in 75% celery extract (Apium graveolens L.) 5 days and 15 days had greater value in color change than alkaline peroxide solution. Keywords: Heat cured type Acrylic resin, Alkaline peroxide, 75% celery extract (Apium graveolens L), Color Change.

Determination of propyl gallate in edible oil by high-performance liquid chromatography with chemiluminescence detection

ABSTRACTA novel and convenient method based on high-performance liquid chromatography coupled with chemiluminescence (HPLC) for the determination of propyl gallate in edible oil is reported. The detection was based on the inhibition of chemiluminescence between luminol and hydrogen peroxide in alkaline solution. The analysis was performed using a C18 column with isocratic 60:40 methanol/water. Under the optimum conditions, the concentration of propyl gallate was linear from 9 × 10−6 mol L−1 to 1 × 10−4 mol L−1 with a detection limit of 2 × 10−7 mol L−1. The method is simple, sensitive, and inexpensive and was used for the determination of propyl gallate in edible oil.

Graphitized carbon materials for electrosynthesis of Н2О2 from О2 in gas-diffusion electrodes

New graphitized carbon materials: technical carbon N220, С140, and СН85 (Omsktekhuglerod) were studied as catalysts of electrosynthesis of alkaline solutions of hydrogen peroxide from oxygen in gasdiffusion electrodes (GDEs). The kinetic parameters of oxygen reduction in alkaline solution and the capacity of gas-diffusion electrodes based on technical carbon N220, С140, and СН85 were determined. Data on the kinetics of hydrogen peroxide accumulation were obtained at different current densities. The fraction of current γ spent on the reduction of oxygen to hydrogen peroxide was determined. The rate constants of hydrogen peroxide decomposition under the given conditions were calculated.

Determination of Dopamine Using the Alkaline Luminol–Hydrogen Peroxide System for Sequential Injection–Zone Fluidics Analysis

ABSTRACTLuminol–hydrogen peroxide chemiluminescence was used with photon counting in a tubular reactor with sequential injection analysis and zone fluidics for the determination of dopamine. The analyte was zone stacked and sandwiched between alkaline luminol and hydrogen peroxide solutions separated by air bubbles within head and tail zones inside a holding coil. These zones were reversed and rapidly dispensed into the reactor with zone penetration and trapped inside the cell for measurement by fluid stopped-flow techniques. The linear concentration range for dopamine was from 10−8 to 10−6 mol/L with a relative standard deviation of 3.30% and a limit of detection of 2.60 × 10−9 mol/L. The system provided a relative standard deviation of 2.57% and was used for the determination of dopamine in pharmaceuticals with a recovery of 99.63%.