Effect Of Peroxide Concentration Research Articles

Effect of peroxide concentration on the epoxidation of vegetable seed oil

The present study focuses on the development of a novel epoxidized vegetable oil (EKO) prepared by the insitu epoxidation of Karingotta oil (KO), a non-edible feedstock with high iodine value (119 g/100 g oil). The key parameters that affect the epoxidation reaction are temperature, time, molar ratio of DB (No. of double bonds in oil): H2O2, molar ratio of DB: CH3COOH and the amount of catalyst. The effect of molar ratio of DB:H2O2 on the epoxidation of Karingotta oil is presented here. Epoxidation was carried out at three different ratios of DB: H2O2 viz, 1:1.1 (P1.1), 1:1.5 (P 1.5) and 1:2.0 (P2.0). The determination of iodine value indicated that the double bond conversion was higher for P1.5 in comparison to P1.1 and P2.0. The increase in the concentration of peroxide from 1.5 to 2.0 did not affect the double bond conversion. Further, the oxirane value increased for P1.5 compared to P1.1 However, for P2.0, the oxirane value reduced indicating the possibility of ring opening side reaction of epoxy group at higher concentration of H2O2. FTIR spectra of all the epoxidized samples exhibited characteristic peak at 827 cm−1 confirming the formation of epoxy functionality in the oil. Quantitative estimation of epoxidation was carried out using 1H NMR which indicated 43 % epoxidation for P1.1, 54 % epoxidation for P1.5 and 43 % epoxidation for P2.0. The iodine value, oxirane value and 1H NMR spectral analysis revealed that a DB:H2O2 ratio of 1:1.5 can promote significant epoxidation of Karingotta oil which can be a potential source for epoxy prepolymers.

Effects of Hydrogen Peroxide Concentration and Heat Treatment on the Mechanical Characteristics and Corrosion Resistance of Hydroxyapatite Coatings

Effects of Hydrogen Peroxide Concentration and Heat Treatment on the Mechanical Characteristics and Corrosion Resistance of Hydroxyapatite Coatings

Investigation of the structure, filler interaction and degradation of disulfide elastomers made by Reversible Radical Recombination Polymerization (R3P)

In this paper we report the synthesis and analysis of cyclic polydisulfides, their redox depolymerization as well as their interaction with carbon black. Cyclic poly(3,6-dioxa-1,8-octanedithiol)s (pDODT) were synthesized by Reversible Radical Recombination Polymerization (R3P). R3P is a scalable “green” polymerization process using triethylamine (TEA), H2O2 and air for the polymerization of dithiol monomers. pDODTs were synthesized in 5 and 20 g batches. The effect of peroxide concentration (3, 5, 10, 20, 30 %) was investigated. It was found that the molecular weights increased exponentially with increasing peroxide concentrations. At 30 % peroxide concentration pDODTs with Mn up to 400,000 g/mol and polydispersity of 2 were obtained. 700 and 800 MHz NMR were used for investigating the chemical structure of the polymers. The absence of thiol end group signals in polymers made with > 10 wt % H2O2 and Mn < 100,000 g/mol, including a sample of a fractionated polymer with starting Mn = 600,000 g/mol, verified cyclic structures. Dithiothreitol reduced the polymers to monomer and a small percentage of oligomers. Carbon black was shown to increase the moduli of high molecular weight pDODTs. Swelling tests in chloroform showed that polymers made with 20 and 30 w% peroxide swelled 14 and 10 times of their starting weight without dissolving, indicating chemical interaction between the polymers and carbon black. Further analysis of these interesting elastomers, available at the 20 g scale, is in progress.

PENGARUH KONSENTRASI HIDROGEN PEROKSIDA DAN WAKTU PROSES BLEACHING TERHADAP KARAKTERISTIK SELULOSA SERAT SABUT KELAPA (Cocos nucifera L.)

Indonesia is the largest coconut producing country in the world. The abundant potential of coco fiber has not been fully utilized optimally. The purpose of this study was to determine the effect of hydrogen peroxide concentration and time of the bleaching process on the cellulose’s characteristics of coconut fiber, as well as to determine the concentration of hydrogen peroxide and time of the bleaching process to produce cellulose from coconut fiber with the best characteristics. This study used a factorial Randomized Block Design with two treatment factors, namely the concentration of H2O2 (K) (20%, 30% and 40%) and the bleaching process time (W) (60 minutes and 120 minutes). Variables observed were yield, degree of whiteness, cellulose, hemicellulose and lignin. The concentration of hydrogen peroxide and the time of the bleaching process affect the yield, whiteness, cellulose, hemicellulose and lignin on cellulose of coconut fiber. The interaction between treatments affected the degree of whiteness, cellulose, hemicellulose, and lignin but had no effect on the yield of the bleached coconut fiber. The best treatment in the bleaching process to produce cellulose from coco fiber is the combination of 40% hydrogen peroxide concentration and 120 minutes of bleaching time. The cellulose characteristics of coco fiber produced were yield, whiteness, cellulose, hemicellulose and lignin is 38.45±2.51%, 76.23±1.54%, 90.19±0.66 %, 5.53±0.58%, and 3.66±0.18%, respectively.

Cold plasma-activated hydrogen peroxide aerosols inactivate Salmonella Typhimurium and Listeria innocua on smooth surfaces and stem scars of tomatoes: Modeling effects of hydrogen peroxide concentration, treatment time and dwell time

This study was conducted to evaluate the effects of hydrogen peroxide (H 2 O 2 ) concentration, treatment time, and dwell time on the efficacy of cold plasma-activated hydrogen peroxide aerosols against bacteria on stem scar and smooth surfaces of tomatoes. Cherry tomatoes inoculated with cocktails of Salmonella Typhimurium and Listeria innocua on the smooth surface and stem scar area were treated for 10, 20 and 30 s followed by 15 and 30 min dwell times in a treatment chamber with cold plasma-activated aerosols generated from 0, 1, 2, 3, 4 and 6% and 7.8% H 2 O 2 . Results showed that the efficacy of the treatments was mostly influenced by the H 2 O 2 concentration and treatment time. The reductions of the two bacteria were modeled as sigmoidal or exponential functions of H 2 O 2 . The models indicated that at H 2 O 2 concentrations ≥4.2%, the treatments reduced populations of L. innocua to non-detectable levels (detection level: 0.70 log CFU/piece) achieving an average 5 log reduction on the smooth surface of tomatoes for all tested treatment times and dwell times. To achieve an average 5-log reduction of Salmonella populations on the smooth surface, H 2 O 2 at concentrations ≥5.7% H 2 O 2 was required. On the stem scar area of tomatoes, populations of Listeria and Salmonella were reduced by less than 2 logs. Our results demonstrated that the efficacy of cold plasma-activated hydrogen peroxide aerosol mainly depended on the concentration of H 2 O 2 , and type and location of inoculated bacteria. • Three main parameters for cold plasma-activated H 2 O 2 process were evaluated. • Non-linear regression models were developed for estimating the efficacy of H 2 O 2 . • Listeria was more sensitive to the activated H 2 O 2 aerosol than Salmonella on tomatoes. • At ≥5.7% H 2 O 2 , both bacteria on the surface of tomatoes were reduced by 5 logs. • Bacteria on stem scar area were more difficult to inactivate than those on surface.

The effect of hydrogen peroxide concentration and water temperature on yellowtail kingfish Seriola lalandi in a repeated bathing treatment

Hydrogen peroxide is routinely used in commercial yellowtail kingfish culture to treat monogenean infections. As the culture of this species expands into warmer geographical areas, this study aimed to compare the effects of a repeated exposure to different hydrogen peroxide concentrations at two rearing temperatures, 18 and 26 °C. The repeat bath occurred 14 days after the initial bath in line with commercial treatment regimes. The three concentrations tested were 85, 170 and 340 mg L−1, with bathing conducted for 30 min. Mortality occurred following the second bath at 340 mg L−1 at 26 °C.The highest hydrogen peroxide dose caused epithelial lifting in gill filaments and significantly reduced the size and abundance of common mucus cells within the skin epithelium following the repeat bath in warm water. Despite the highest dose causing gill damage and mortality in warm water, there were no significant effects of hydrogen peroxide concentration on any of the conventional blood parameters, except in moribund fish. A novel measurement of plasma thiol oxidation, however, was found to be significantly elevated at the highest bathing concentration.Whilst yellowtail kingfish appeared to be tolerant of the high concentration of hydrogen peroxide tested in the current study at ambient water temperature, these fish were not infected with monogeneans, and any such burden is likely to increase the susceptibility of the fish to the effects of hydrogen peroxide.

Effects of Hydrogen Peroxide Concentration on Properties of Black Silicon Fabricated by Two-Step Silver-Assisted Wet Chemical Etching for Photovoltaics

Crystalline silicon (c-Si) has low optical absorption due to its high surface reflection of incident light. Nanotexturing of c-Si which produces black silicon (b-Si) offers a promising solution. In this work, effect of H2O2 concentrations towards surface morphological and optical properties of b-Si fabricated by two-step silver-assisted wet chemical etching (Ag-based two-step MACE) for potential photovoltaic (PV) applications is presented. The method involves a 30 s deposition of silver nanoparticles (Ag NPs) in an aqueous solution of AgNO3:HF (5:6) and an optimized etching in HF:H2O2:DI H2O solution under 0.62 M, 1.85 M, 2.47 M, and 3.7 M concentrations of H2O2 at 5 M HF. On the b-Si, nanowires with 250-950 nm heights and an average diameter of 150-280 nm are obtained. Low concentrations of H2O2 result in denser nanowires with an average length of 900-950 nm and diameters of about 150-190 nm. The b-Si exhibit outstanding broadband antireflection due to the refractive index grading effect represented as WAR within the 300-1100 nm wavelength region. B-Si obtained after etching in a solution with 0.62 M concentration of H2O2, demonstrate WAR of 7.5%. WAR of 7.5% results in an absorption of up to 95.5 % at a wavelength of 600 nm. The enhanced broadband light absorption yields maximum potential short-circuit current density (Jsc(max)) of up to 38.2 mA/cm2, or 45.2% enhancement compared to the planar c-Si reference.

Effect of Hydrogen Peroxide Concentration to Fluorescence Properties of Carbon Dot from HDPE

This research paper describes the effect of hydrogen peroxide concentrations (0; 1; 3; 5 and 7 wt%) on fluorescence properties of carbon dots (CDs) from high-density polyethylene (HDPE) plastic. Synthesis of CDs has been carried out using modified pyrolysis and hydrothermal methods. The CDs obtained were characterized by FTIR, XRD, UV-Visible and fluorescence spectrophotometer. Based on UV-Visible spectra, the maximum wavelength of carbon dot ranges from 287 to 291 nm, indicating there is an π -π* electron transition belonging to the core site (C=C), then the absorption widens to 400 nm which indicated n-π* electron transition relating to the CDs surface functional group (carbonyl, hydroxyl, and carboxyl). The use of hydrogen peroxide (5 wt%) can produce CDs with the best fluorescence properties based on fluorescence spectra. CDs has a structure like graphite which is rich in functional groups on its surface. The photocatalytic activity of carbon dot has been tested and it showed that CDs can degrade methylene blue (MB) dye under visible light (80.3%).

Electrochemical Investigation of the Effect of Hydrogen Peroxide Concentration on Platinum-Particle-Assisted Etching of p-Type Silicon in a Hydrofluoric Acid Solution

Metal-assisted etching (metal-assisted chemical etching) has attracted increasing attention as a low-cost and versatile microfabrication technique of semiconductors. In platinum (Pt)-particle-assisted etching of silicon (Si), a composite structure of straight macropores and a mesoporous layer can be produced, but the mechanism of the structure formation is still open to discussion. We employed an electrochemical approach to investigate the composite structure formation by the Pt-assisted etching. Polarization curves of Pt-deposited Si and bare Si were measured in hydrofluoric acid (HF) solutions containing different concentrations of hydrogen peroxide (H2O2). The open circuit potential during the Pt-assisted etching was more positive than that of the bare Si and it shifted in the positive direction with increasing the H2O2 concentration as a consequence of the enhancement of the H2O2 reduction reaction. For the structure observation, both the macropore depth and the mesoporous layer thickness increased with increasing the H2O2 concentration, while the ratio between them changed. We discussed the structure change on the basis of the polarization characteristics. The mesoporous layer formation can be explained by the hole consumption at the Si surface under the positive potential which is determined by mixed potential theory.

Influence of Bleaching Gel Peroxide Concentration on Color and Penetration through the Tooth Structure

The purpose of this study was to assess the effect of hydrogen peroxide concentration on the bleaching efficacy and penetration through the tooth structure. One hundred enamel/dentin specimens with cylindrical shape were obtained from bovine incisors. The surfaces were polished and the size standardized. They were divided into five groups (n = 20), following the concentration of hydrogen peroxide in the bleaching gels: 20, 25, 30, 35, and 40% (w/w). The specimens were placed over artificial pulpal chambers containing acetate buffer solution and bleached for 30 minutes (three applications of 10 minutes each). Aliquots of the acetate solution were collected, and the peroxide concentration was measured by an analytic spectrophotometer. The color of the samples was analyzed using a colorimetric spectrophotometer at the baseline and 7 days after the bleaching procedure. The color difference was calculated using the ∆Eab formula. The data were analyzed by one-way ANOVA and Tukey's test (p <0.05). The peroxide concentrations of 20-30% showed smaller bleaching effect than the higher concentrations (p = 0.001). The peroxide penetration was significantly higher (p = 0.001) for the more concentrated gels (35 and 40%). The higher peroxide concentrations enhance the bleaching efficacy, but also increased the peroxide penetration through the tooth structure. In-office bleaching gels with higher concentrations of hydrogen peroxide (35 and 40%) present superior whitening efficacy. Nevertheless, they might also intensify the negative biological effects on the pulpal tissue, since they exhibit increased penetration potential. How to cite this article: Torres CRG, Zanatta RF, Godoy MMM, et al. Influence of Bleaching Gel Peroxide Concentration on Color and Penetration through the Tooth Structure. J Contemp Dent Pract 2021;22(5):479-483.

Adsorption of elemental mercury in flue gas using biomass porous carbons modified by microwave/hydrogen peroxide

In order to enhance the mercury adsorption capacity of bio-char and reduce the potential environmental damage caused by modification methods, a clean modification method combining microwave activation and H2O2 impregnation of bio-char was proposed in this paper. The effects of hydrogen peroxide concentration, reaction temperature and flue gas components (NO/O2/SO2/H2O) on Hg0 removal efficiency of the modified samples were studied. The physicochemical properties of the biomass porous carbons were analyzed by various characterization methods (i.e. BET, SEM, FTIR, XPS). The results show that the biomass porous carbons, WSW10 and RSW10, exhibit the best Hg0 adsorption performance at 130 ℃. Microwave activation and hydrogen peroxide modification can increase the specific surface area to improve the pore structure of biomass porous carbons. The number of surface functional groups of biomass porous carbons can be increased by the H2O2 impregnation, which can improve the Hg0 removal performance of biomass porous carbons. O2 and NO contribute to the removal of Hg0. With the increase of SO2 or H2O concentration, the Hg0 removal efficiency decreases. The results of kinetic simulation show that the pseudo-second-order model can well fit the mercury adsorption process of the modified biomass porous carbons, and chemisorption occurs on the surface of the adsorbent. The C-O functional groups and chemically adsorbed oxygen play an important role in the Hg0 removal.

Effect of hydrogen peroxide concentration on the maintenance and differentiation of cultured skeletal muscle cells

We have studied the effects of hydrogen peroxide (H2O2) on the differentiation and maintenance of C2C12 myoblasts. The effects of H2O2 were evaluated by cell viability, total protein concentration, the relative amount of muscle-related proteins, sarcomere structure, and active tension generation. Oxidative stress is one of the major causes of myopathy after exercise and thus establishing the method to evaluate the effects on muscle function is essential. The primary function of striated muscle is to generate force, thus, the measurement of active tension is important in assessing the effect of chemicals on muscle. Among the indices we tested, the sarcomere structure was the most sensitive to the H2O2 exposure while the cell viability was less sensitive. The effects of H2O2 on active tension correlated with a decrease in the amount of muscle proteins. In this study, our results showed that the effect of chemicals on muscle should be measured in multiple ways, including active tension generation, for a better understanding of its physiological impact.

Effect of Mordant Bleaching on the Optical and Mechanical Properties of Black Tunisian Wool and Optimization of the Bleaching Process

ABSTRACT White wool occupies a very important place on the commercial market because it can be dyed in any color. In nature, however, wool fibers are usually found white but may be black; sometimes they are shades of white, yellow and, in some cases, brown or black, because of their natural pigment, melanin. In this study, copper sulfate and iron sulfate were used in the treatment of Tunisian wool (Black of Thibar) to evaluate their effectiveness in terms of color removal and minimal damage to wool fibers. Once the most effective mordant agent was chosen, the effects of hydrogen peroxide concentration, bleaching time, and temperature on the wool sample bleaching were studied. The results showed that iron sulfate is the most effective mordant agent in the bleaching process of pigmented wool for a good base of dyeing and finishing, since it guarantees the best optical properties with the minimum damage to the fibers. In addition, it was found that the optimal bleaching was achieved for a hydrogen peroxide concentration of 87.5 mL/L, a treatment time of about 90 min and a temperature of about 60#xB0;C.

Using hydrogen peroxide to supplement oxygen for nitrogen removal in constructed wetlands

Nitrification is often the main mechanism to remove ammonium in constructed wetlands. An important factor hindering this biochemical process in constructed wetlands is the availability of dissolved oxygen. This study introduced hydrogen peroxide-based chemical oxygenation to saturated vertical flow constructed wetlands for removal of nitrogen. Hydrogen peroxide is decomposed into water and oxygen in the presence of catalase. Three hydrogen peroxide concentrations, 0.6%, 1% and 2% (w/v), were applied over three operating periods at the same dosage to test the effects of hydrogen peroxide concentration on nitrogen removal and growth of wetland plants in secondary effluent. More than 92% ammonia was removed in all the three periods. Ammonia removal via nitrification was not adversely affected by hydrogen peroxide at the tested concentrations. As hydrogen peroxide dosing concentration was increased, concentration of nitrate in the effluent decreased substantially due to stimulated plant growth and plant uptake of nitrate instead of ammonia. Dosing hydrogen peroxide to constructed wetlands extended ammonia removal via nitrification to total inorganic nitrogen removal by nitrification and stimulated plant uptake of nitrate. The optimum dosing solution appeared to be 1–2% hydrogen peroxide.

Investigation of alkaline hydrogen peroxide pretreatment to enhance enzymatic hydrolysis and phenolic compounds of oil palm trunk.

Alkaline hydrogen peroxide (AHP) as a pretreatment effectively enhances the increasing enzymatic digestibility of oil palm trunk (OPT) for conversion to biofuels and bioproducts in the biorefinery processes. The effect of hydrogen peroxide concentration (1-5%), temperature (50-90°C), and time (30-90min) were studied to find out the optimum condition for the removal of lignin. The optimum condition attained at 70°C, 30min, and 3% H2O2 g /g of biomass not only increased the cellulose content from 38.67% in raw material to 73.96% but also removed lignin and hemicellulose up to 50% and 57.12%, respectively. The AHP-treated fibers subjected to enzyme hydrolysis showed significant improvement in glucose concentration that increased from 11.77 (± 0.84) g/L (raw material) to 46.15 (± 0.32) g/L with 59.82% enzyme digestibility at 96h. Scanning electron microscopy (SEM) and Fourier transformation infrared (FT-IR) were employed to analyze the morphology and structural changes of untreated and AHP-treated fibers. SEM results showed disruption of the intact OPT structure resulting in increase of enzyme accessibility to cellulose. The FT-IR identified changes in peaks which indicated structural transformation and dissolution of both lignin and hemicellulose molecules caused by AHP treatment. The black liquor obtained from AHP treatment contained about 5.13mg gallic acid equivalent (GAE)/g of dry sample of total phenolic content (TPC) and an antioxidant activity of 59.80% and 65.51% inhibitions of DPPH and ABTS assays, respectively. Hence, it is a sustainable approach to utilize waste for the recovery of multiple value-added products during pretreatment process.

Effect of Hydrogen Peroxide Concentration on 100% Cotton Knit Fabric Bleaching

This paper focuses on the effect of different concentration of hydrogen peroxide (an oxidizing bleaching agent) on 100% single jersey cotton knit fabric. Five different concentrations (25%, 30%, 35%, 40% and 45%) of hydrogen peroxide solution (5% stock solution) were adopted for this experiment. For each individual concentration, bleaching was performed in three different quantities (6gm/L, 8gm/L and 10gm/L) at the same temperature (100˚C) and same time (60 minute) cycle. 5gm samples were taken where 1:10 material and liquor ratio was maintained in each operation. Spectrophotometer (data color 650) was used to test the reflectance of all bleached samples, and their bursting strengths were measured by an Auto burst instrument following ISO 13938-1 method. The effects of hydrogen peroxide concentration on various physical properties such as weight loss, absorbency, GSM, bursting strength, and whiteness was studied to minimize the cost of bleaching process by optimizing the concentration of hydrogen peroxide. As majority of industries have concerned to alineate the production cost with maximum quality assurance which has been obtained through bleaching at 30% concentration.

Effect of hydrogen peroxide concentration on the nanostructure of hydroxyapatite coatings via ultrasonic-assisted electrodeposition

Hydroxyapatite (HA) coating is prepared by ultrasonic-assisted electrodeposition from the electrolytes containing hydrogen peroxide (H2O2). Effects of H2O2 concentrations (0, 0.5, 2.0, 4.0 mL/L) on the morphology, chemical bonds, crystallinity and roughness of the HA coatings are investigated. The results show that the HA coating via ultrasonic-assisted electrodeposition is spindle-like in the absence of H2O2, but becomes flake-like and wrinkle-like morphology after adding different concentrations of H2O2 into the electrolyte. The SEM image of HA coating at half of the deposition time (i.e. 30 min) reveals the transition from spindle-like to wrinkle-like. TEM image shows that wrinkle-like HA coating electrodeposited at 4.0 mL/L H2O2 is also found with spindle-like HA crystal nanostructure. The influencing mechanism of H2O2 on the HA coating nanostructure is also proposed. This study provides a new idea for the preparation of hydroxyapatite electrodeposited coatings.

The effect of hydrogen peroxide concentration on the partial oxidation of methane to methanol in an atmospheric dielectric barrier discharge

It was proved that atmospheric non-equilibrium plasma can be deemed as “reaction carrier”, and is an effective method of partial oxidation of methane to methanol and other higher hydrocarbons. In this paper, hydrogen peroxide vapor is selected as oxygen-containing oxidizer and used to activate and convert methane into methanol in an atmospheric dielectric barrier discharge. A detailed axisymmetric 2D fluid model in CH4/H2O/H2O2 gas mixture is developed, with an emphasis on gas-phase plasma chemistry for partial oxidation of methane and methanol formation. Especially, the effect of hydrogen peroxide concentration on the conversion of methane to methanol is studied. The spatial and temporal distributions of various plasma species are shown as a function of hydrogen peroxide concentration. In addition, the main plasma species and reaction pathways governing the production and loss of CH3OH and OH are determined. It is shown that the increasing hydrogen peroxide concentration results in increase of OH and CH3OH production. Hydroxyl appears to play a significant role during the process of methanol synthesis, which is primarily produced by electron-impact dissociation of H2O2 and H2O molecules.

Humic like substances for the treatment of scarcely soluble pollutants by mild photo-Fenton process

Humic-like substances (HLS) extracted from urban wastes have been tested as auxiliaries for the photo-Fenton removal of thiabendazole (TBZ) under simulated sunlight. Experimental design methodology based on Doehlert matrices was employed to check the effects of hydrogen peroxide concentration, HLS amount as well as TBZ loading; this last parameter was studied in the range 25–100 mg/L, to include values below and above the limit of solubility at pH = 5. Very satisfactory results were reached when TBZ was above solubility if HLS and H2O2 amounts were high. This could be attributed to an interaction of HLS-TBZ that enhances the solubility of the pollutant. Additional evidence supporting the latter interaction was obtained by fluorescence measurements (excitation emission matrices) and parallel factor analysis (PARAFAC).

Effects of Hydrogen Peroxide Concentration and Activation Time on Hydroxyl Radical Generation and the Bleaching Effect

Effects of Hydrogen Peroxide Concentration and Activation Time on Hydroxyl Radical Generation and the Bleaching Effect