Kinetics Of Hydrogen Peroxide Decomposition Research Articles

Microfluidic-based in-situ determination for reaction kinetics of hydrogen peroxide decomposition

In this work, a microfluidic approach was presented to study the reaction kinetics of hydrogen peroxide (H2O2) decomposition. The production rate of oxygen correlated to the volume change of bubbles in microchannel via in-situ visualization in order to characterize H2O2 decomposition. Kinetic models were established to determine the reaction rate constant and activation energy of H2O2 decomposition reaction as a function of temperature, initial mass fraction of H2O2, light intensity, and pH value. Meanwhile, the reaction density functional theory calculation indicated a good agreement with the conclusions from the experimental observations. This method provides a rapid, accurate and common approach to determine the kinetics of liquid-to-gas decomposition reactions. Furthermore, the set of kinetic data are beneficial to the process optimization of reactions involving H2O2.

Kinetics of hydrogen peroxide decomposition catalyzed by Cu‐buserite over a well‐sealed and thermostated kinetics assembly

AbstractHerein a well‐sealed and thermostated kinetics assembly is designed and built, which can run stirred at different reaction temperatures. With the reaction assembly above and the volumetric method together, the hydrogen peroxide (H2O2) decomposition reaction kinetics is systematically investigated under a variety of reaction conditions over a copper‐doped buserite‐type layer manganese oxide (referred to as Cu‐buserite) as a heterogeneous catalyst. The overall second‐order rate law is fitted out by the linear regression analysis, with the reaction orders with respect to both H2O2 and Cu‐buserite determined to each be equal to 1, and then explicitly explained by the proposed Michaelis‐Menten like mechanism. The apparent activation energy Ea is estimated as 33.5 ± 2.5 kJ mol−1.

Mechanism and Kinetics of Hydrogen Peroxide Decomposition on Platinum Nanocatalysts.

The decomposition of H2O2 to H2O and O2 catalyzed by platinum nanocatalysts controls the energy yield of several energy conversion technologies, such as hydrogen fuel cells. However, the reaction mechanism and rate-limiting step of this reaction have been unsolved for more than 100 years. We determined both the reaction mechanism and rate-limiting step by studying the effect of different reaction conditions, nanoparticle size, and surface composition on the rates of H2O2 decomposition by three platinum nanocatalysts with average particle sizes of 3, 11, and 22 nm. Rate models indicate that the reaction pathway of H2O2 decomposition is similar for all three nanocatalysts. Larger particle size correlates with lower activation energy and enhanced catalytic activity, explained by a smaller work function for larger platinum particles, which favors chemisorption of oxygen onto platinum to form Pt(O). Our experiments also showed that incorporation of oxygen at the nanocatalyst surface results in a faster reaction rate because the rate-limiting step is skipped in the first cycle of reaction. Taken together, these results indicate that the reaction proceeds in two cyclic steps and that step 1 is the rate-limiting step. Step 1: Pt + H2 O2 → H2 O + Pt( O). Step 2: Pt( O) + H2 O2 → Pt + O2 + H2 O. Overall: 2 H2 O2 → O2 + 2 H2 O. Establishing relationships between the properties of commercial nanocatalysts and their catalytic activity, as we have done here for platinum in the decomposition of H2O2, opens the possibility of improving the performance of nanocatalysts used in applications. This study also demonstrates the advantage of combining detailed characterization and systematic reactivity experiments to understand property-behavior relationships.

Thermodynamic Analysis and Kinetics of Etching of Thin PbS Films in Hydrochloric Acid Solutions

A hydrochloric acid solution of hydrogen peroxide was suggested for etching lead sulfide films. The solubility of lead sulfide in relation to the hydrochloric acid concentration in the etching solution was calculated using thermodynamic analysis, taking into account the stability of lead complex species. The kinetics of hydrogen peroxide decomposition in the hydrochloric acid solution was studied, and the formal rate equation of the process was constructed.

Kinetics of the Decomposition of Hydrogen Peroxide in Acidic Copper Sulfate Solutions

A study on the decomposition kinetics of hydrogen peroxide in a solution of dilute sulfuric acid with added copper sulfate has been undertaken. The experiments were performed in a vacuum/Dewar flask, and the temperature of the reacting mixture was measured as a function of time. Because the decomposition was exothermic, the relationship between the temperature and time during the decomposition process was used to analyze the reaction kinetics. The decomposition reaction of hydrogen peroxide was found to be first-order, as reported by most of the previous researchers. It was found that, at an initial temperature of 67 °C, the decomposition of pure peroxide in dilute sulfuric acid had a rate constant of 0.0385 min–1. The addition of 5 g of copper sulfate increased the rate constant to 0.265 min–1, and with a further addition of copper sulfate, it asymptoted to 0.463 min–1. It was further rather surprisingly noted that the exothermic reaction was followed by an endothermic one that did not appear to be affec...

Hydrogen peroxide decomposition kinetics in aquaculture water

Hydrogen peroxide (HP) is used in aquaculture systems where preventive or curative water treatments occasionally are required. Use of chemical agents can be challenging in recirculating aquaculture systems (RAS) due to extended water retention time and because the agents must not damage the fish reared or the nitrifying bacteria in the biofilters at concentrations required to eliminating pathogens. This calls for quantitative insight into the fate of the disinfectant residuals during water treatment. This paper presents a kinetic model that describes the HP decomposition in aquaculture water facilitated by microbial enzyme activity. The model describes how the hydrogen peroxide removal declines and eventually stops at relatively low chemical oxygen demand (COD) concentrations. It is hypothesized that this is due to an enzyme deficit because it is destructed due to the reactive radicals created during the HP decomposition. The model assumes that the enzyme decay is controlled by an inactivation stoichiometry related to the HP decomposition. In order to make the model easily applicable, it is furthermore assumed that the COD is a proxy of the active biomass concentration of the water and thereby the enzyme activity. This was, however, not measured. The model developed successfully described the removal of HP in aquaculture water from three types of RAS and model parameters are estimated. The model and the model parameters provide new information and are valuable tools to improve HP application in RAS by addressing disinfection demand and identify efficient and safe water treatment routines.

Kinetic study of the catalytic decomposition of H2O2 in phosphoric acid medium

The kinetics of hydrogen peroxide decomposition in phosphoric acid media containing ferrous ion was investigated. The results indicated that this reaction followed the pseudo-first-order kinetic model. The decomposition rate of H2O2 was accelerated by increasing Fe2+ concentrations and temperature. However, higher levels of H2O2 inhibited the reaction kinetics. Based on the rate constants obtained at different temperatures, the empirical Arrhenius expression of H2O2 decomposition was derived. The derived activation energy for H2O2 decomposition by ferrous ions is 57.1 kJ/mol.

Performance of blast furnace waste for azo dye degradation through photo-Fenton-like processes

This study investigated the use of blast furnace dust (BFD) as a catalyst to degrade an azo dye (RR195) by photo-Fenton-like processes. This waste contains hematite, magnetite and maghemite as iron sources, and its dissolution provides more Fe3+ than Fe2+ for the Fenton reaction in solution. The effect of hydrogen peroxide concentration and catalyst dosage on the kinetics of hydrogen peroxide decomposition and dye decolorization was also studied. The photo-Fenton-like process was compared to Fenton-like (using BDF without irradiation), Fenton and photo-Fenton (using FeSO4 as iron source), UV/H2O2 and UV processes. The results indicated that BFD can be effectively used as a catalyst in the photocatalytic process because it was able to completely degrade H2O2 via an adjusted Langmuir–Hinshelwood model. Although the photo-Fenton-like reaction with BFD showed the same decolorization efficiency of RR195 as the homogeneous photo-Fenton process (using FeSO4), the catalyst considerably increased the reaction rates (more than five times) according pseudo-first-order kinetics. The results of the irradiated systems using BFD can be more efficient in dye decolorization due to greater hydroxyl radical production through Fe2+/Fe3+ cycling and by the occurrence of homogeneous and heterogeneous reactions. The practical use of the steel waste is promising, because it increases the reaction rates and its high density and magnetic proprieties enable an easy solid–liquid separation and reuse, making it a versatile material for environmental applications.

Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst

Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H2O2 concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents.

Metabolic activity and membrane integrity changes in Microcystis aeruginosa – new findings on hydrogen peroxide toxicity in cyanobacteria

The aim of our study was to investigate the intracellular toxicity mechanisms of the photoactive, potentially anti-cyanobacterial agent hydrogen peroxide (H2O2) in Microcystis aeruginosa, which represents one of the most significant toxin-producing cyanobacterial species in European water bodies. Metabolic activity and cell membrane integrity were evaluated by flow cytometry in cyanobacteria exposed to H2O2 in the dark or light; the relationships between exposure effects and the kinetics of hydrogen peroxide decomposition were studied. In the light (irradiance 140 µmol m−2 s−1), cyanobacteria were exposed to initial H2O2 concentrations of 0.00 (control), 0.75, 2.00, and 4.00 mg l−1 respectively, while in the dark concentrations were ten times higher. Flow cytometry and chlorophyll a fluorescence measurements suggested that hydrogen peroxide exposure elicits an immediate decline of metabolic (esterase) activity, measured as a decrease in fluorescein fluorescence after hydrolysis of fluorescein diacetate (FDA), and immediate changes of chlorophyll a fluorescence parameters, followed later by an increase in the percentage of membrane-compromised (SYTOX Green positive) cells. When the concentration of H2O2 used was lethal (in the two highly exposed treatments in the light), a significant drop in total cell counts was detected, whereas in other treatments no drop was observed during the entire experimental period (72 h). Our study also confirmed that light is one of the critical factors affecting H2O2 decomposition and thus greatly influences its toxicity. Whereas in the light, M. aeruginosa exposed to 0.75 mg l−1 H2O2 recovered after all the H2O2 had decomposed, in the dark H2O2 decomposed relatively slowly and its toxic effects on the cyanobacteria were observed over the whole 72-h period, though without cell lysis in any experimental concentration.

Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects

The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydrophobicity (log P), concentration of hydroxyl groups ([OH]), polarizability (α), Kamlet-Taft parameter (β) and Kosower parameter (Z). The relationships between the initial rate, kinetic constants and medium properties are analyzed by linear and multiple linear regression.

High-Temperature Epoxidation of Soybean Oil in Flow—Speeding up Elemental Reactions Wanted and Unwanted

The soybean oil epoxidation reaction is investigated theoretically through kinetic modeling of temperature effects enabled through flow processing under superheated conditions. Different from previous studies on such processing, here a complex reaction network superimposed by multiphase transport is considered; with one elemental step—the hydrogen peroxide decomposition—which can defeat the much boosted product formation. For such a delicate reaction network, the accessibility of accurate and reliable kinetics is absolutely essential, especially when exploring this completely new temperature range. Initially, an overview of the actual kinetic models is given, this gives rise to implications for the study developed here considering high temperature flow processing, heat removal efficiency, hotspot formation, and the effect of different hydrogen peroxide decomposition kinetics. Subsequently an optimized process involving the use of microreactors at different temperatures is proposed for the process manageme...

Batch and Semibatch Partial Oxidation of Starch by Hydrogen Peroxide in the Presence of an Iron Tetrasulfophthalocyanine Catalyst: The Effect of Ultrasound and the Catalyst Addition Policy

Oxidized starch is important for paper coating because of its good mechanical and sizing properties. Traditionally, starch oxidation is performed by different heavy metals as catalysts and chlorites or chlorines as oxidizing agents. In this study, an environmentally friendly method was developed, utilizing iron tetrasulfophthalocyanine as a catalyst only in small amounts and hydrogen peroxide as a clean oxidant. It has been previously shown that the method works well, but analysis of the kinetic data as well as catalyst deactivation was difficult because of the semibatch operation mode. In this study, hydrogen peroxide was employed in a batch mode, allowing more simple analysis methods for determining the degree of substitution, starch degradation, and hydrogen peroxide decomposition kinetics. Additionally, the effect of adding the catalyst continuously into the solution, as well as the influence of ultrasound treatment on starch prior to oxidation, was studied. The batch-mode results showed DSCOOH = 0.73 for 100 anhydroglucose units at 52 °C and pH 10, whereas adding the catalyst continuously increased DSCOOH to 1.62. An increased DSCOOH was obtained with the ultrasound-treated starch, which shows that ultrasound is a promising method for enhancing the reaction performance.

Catalase Activity of Cytochrome c Oxidase Assayed with Hydrogen Peroxide-Sensitive Electrode Microsensor

An iron-hexacyanide-covered microelectrode sensor has been used to continuously monitor the kinetics of hydrogen peroxide decomposition catalyzed by oxidized cytochrome oxidase. At cytochrome oxidase concentration ~1 µM, the catalase activity behaves as a first order process with respect to peroxide at concentrations up to ~300-400 µM and is fully blocked by heat inactivation of the enzyme. The catalase (or, rather, pseudocatalase) activity of bovine cytochrome oxidase is characterized by a second order rate constant of ~2·10(2) M(-1)·sec(-1) at pH 7.0 and room temperature, which, when divided by the number of H2O2 molecules disappearing in one catalytic turnover (between 2 and 3), agrees reasonably well with the second order rate constant for H2O2-dependent conversion of the oxidase intermediate F(I)-607 to F(II)-580. Accordingly, the catalase activity of bovine oxidase may be explained by H2O2 procession in the oxygen-reducing center of the enzyme yielding superoxide radicals. Much higher specific rates of H2O2 decomposition are observed with preparations of the bacterial cytochrome c oxidase from Rhodobacter sphaeroides. The observed second order rate constants (up to ~3000 M(-1)·sec(-1)) exceed the rate constant of peroxide binding with the oxygen-reducing center of the oxidized enzyme (~500 M(-1)·sec(-1)) several-fold and therefore cannot be explained by catalytic reaction in the a(3)/Cu(B) site of the enzyme. It is proposed that in the bacterial oxidase, H2O2 can be decomposed by reacting with the adventitious transition metal ions bound by the polyhistidine-tag present in the enzyme, or by virtue of reaction with the tightly-bound Mn2+, which in the bacterial enzyme substitutes for Mg2+ present in the mitochondrial oxidase.

Kinetics of phenol mineralization by Fenton-like oxidation

The kinetics of hydrogen peroxide decomposition and the mineralization rate of phenol in homogeneous aqueous solution (pH < 3) via Fenton-like reaction were studied. Results were correlated with the generation of hydroxyl radicals as well as with iron speciation. Batch experiments were carried out in de-ionized water in a completely mixed batch reactor under a wide range of experimental conditions (3500 ≤ [H 2O 2] ≤ 8250 mg/L; 100 mg/L ≤ [Fe] ≤ 2350 mg/L; 2.5 ≤ [H 2O 2]/[Fe] ≤ 83; 0 mg/L ≤ [TOC] ≤ 1000 mg/L). Results demonstrated that the rate of hydrogen peroxide decomposition, phenol mineralization and ferrous ions formation depended on both the initial concentration of the phenol and on the weight ratio between hydrogen peroxide and iron. A linear correlation was found between the mineralization rate of phenol and the decomposition rate of hydrogen peroxide indicated that 10 g of hydrogen peroxide was required to mineralize 1 g of phenol.

Design of In Situ Fenton Oxidation Based on the Integration of Experimental and Numerical Modelling

AbstractCriteria for the design of In-Situ Fenton Oxidation (ISFO) is proposed and applied to the development of a pilot-scale treatment of a former refinery site contaminated by hydrocarbons. The proposed criteria takes in account both the regulatory and technical constraints that typically characterize the application of in situ remediation technologies. The proposed design strategy of the ISFO treatment is based on coupling experimental and numerical modelling of the ISFO treatment in an iterative way. Batch tests are performed first, allowing to select the optimal operating conditions and the data on hydrogen peroxide decomposition kinetics. These data, together with the hydro-geological information collected in the field, are then used for the numerical modelling of the ISFO treatment, which allows to define the pilot plant layout and operating conditions and to evaluate the effective delivery of the oxidant and the hydraulic gradient developed in the field. These data are then used to design column scale tests aimed to evaluate the effective hydrogen peroxide longevity, the process performance and the extent of gas production from hydrogen peroxide decomposition.

Interaction of Hemin and Hydrogen Peroxide: Effect of Media

Maximum of catalytic activity of hemin (complex of iron(III) with protoporphyrin IX, FePP) in hydrogen peroxide decomposition is shown to correspond to an associated form (evidently, dimer) of FePP. Influence of NaHСO 3 , Na 2 HPO 4 , cetyltrimethylammonium bromide and poly-N-vinylpyrrolidon on kinetics of hydrogen peroxide decomposition catalyzed by FePP and destruction of FePP was studied.

Effect of solvent nature on the catalytic activity of iron-containing pyrocatecholsulfonic cationite in the reactions of H2O2 decomposition and benzene hydroxylation

Kinetics of hydrogen peroxide decomposition under the conditions of heterogenous catalysis with iron-containing pyrocatecholsulfonic cationite at 50°C in dimethyl sulfoxide, tetrahydrofuran, dioxane, acetonitrile, and nitromethane was studied. The value of rate constant of hydrogen peroxide decomposition in these solvents was found to diminish with increase of solvent nucleophilicity. At the hydroxylation of benzene in the aqueous acetonitrile medium the formation of phenol was observed. The phenol yield was found to depend on the composition of the binary solvent acetonitrile-water.

Kinetics and Mechanism of Decomposition of Hydrogen Peroxide over Pd/SiO2 Catalyst

Kinetics of hydrogen peroxide decomposition over Pd/SiO2 catalyst was investigated as part of a larger project to determine the overall kinetics of hydrogen peroxide formation by Pd/SiO2 catalyzed direct combination of hydrogen and oxygen. A Pd oxidative/reductive cycle mechanism for the decomposition of H2O2 over Pd/SiO2 was proposed. A Rideal−Eley rate expression based on this mechanism was shown to accurately correlate experimental data over a wide range of H2O2 concentration and temperature. This rate equation was shown to also apply in the presence of stabilizing concentrations of H2SO4.

Photochemistry of Peroxoborates: Borate Inhibition of the Photodecomposition of Hydrogen Peroxide

The UV absorbance and photochemical decomposition kinetics of hydrogen peroxide in borate/boric acid buffers were investigated as a function of pH, total peroxide concentration, and total boron concentration. At higher pH borate/boric acid inhibits the photodecomposition of hydrogen peroxide (molar absorptivity and quantum yield of H(2)O(2) and HO(2) (-), (19.0+/-0.3) M(-1) cm(-1) and 1, and (237+/-7) M(-1) cm(-1) and 0.8+/-0.1, respectively). The results are consistent with the equilibrium formation of the anions monoperoxoborate, K(BOOH)=[H(+)][HOOB(OH)(3) (-)]/([B(OH)(3)][H(2)O(2)]), 2.0 x 10(-8), R. Pizer, C. Tihal, Inorg. Chem. 1987, 26, 3639-3642, and monoperoxodiborate, K(BOOB)=[BOOB(2-)]/([B(OH)(4) (-)][HOOB(OH)(3) (-)]), 1.0+/-0.3 or 4.3+/-0.9, depending upon the conditions, with molar absorptivity, (19+/-1) M(-1) cm(-1) and (86+/-15) M(-1) cm(-1), respectively, and respective quantum yields, 1.1+/-0.1 and 0.04+/-0.04. The low quantum yield of monoperoxodiborate is discussed in terms of the slower diffusion apart of incipient (.)OB(OH)(3) (-) radicals than may be possible for (.)OH radicals, or a possible oxygen-bridged cyclic structure of the monoperoxodiborate.