Hydrogen Peroxide In Aqueous Solution Research Articles

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the safe use of an aqueous solution of hydrogen peroxide, acetic acid and peracetic acid (23/17/15) as a processing aid for the bacterial disinfection of the washing water used for cut carrots and lettuces, peeled garlic, sweet potatoes, persimmons, mangoes and avocados in processing

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the safe use of an aqueous solution of hydrogen peroxide, acetic acid and peracetic acid (23/17/15) as a processing aid for the bacterial disinfection of the washing water used for cut carrots and lettuces, peeled garlic, sweet potatoes, persimmons, mangoes and avocados in processing

Green and efficient two-step degradation approach for converting Powder River Basin coal into fuels/chemicals and insights into their chemical compositions

A green and efficient two-step degradation approach, including supercritical CO2/ethanol degradation and oxidation in aqueous hydrogen peroxide solution, was reported to convert Powder River Basin coal into fuels/chemicals. In total, 43.5 wt% liquid tar and 23.3 wt% oxidation products were obtained from the two-step degradation. The liquid tar was facilely separated into light oil and asphaltene, with yields of 27.3 wt% and 16.5 wt%, respectively. The first-step degradation has high energy recovery (50%) and low energy consumption ratio (minimum 0.17), indicating an energetic net energy gain. The light oil is a promising feedstock as clean liquid fuels due to its high H/C ratio (1.58) and heating value (34.56 MJ/kg). The asphaltene with lower H/C and O/C ratios but higher aromaticity (0.83) could be a good precursor for carbon materials. The light oil can be upgraded into clean liquid fuels by hydrodeoxygenation or used as feedstock for producing oxygenated chemicals because it is rich in oxygenated components. Phenols and aliphatic esters account for 74.2% of the volatile components in the light oil. High resolution mass spectrometric analysis revealed that the O1–O4 class species are dominant components with relative abundance of 71% in the light oil. Valuable carboxylic acids with total yields of 19.7 wt%, especially alkanedioic and alkanetricarboxylic acids, were produced from oxidation of the scCO2/ethanol degradation residue, which is a promising second-step degradation to utilize the residue. This study provides an efficient coal conversion processes for producing fuels/chemicals and reducing energy consumption and environmental impact.

Deposition of a Chitosan Coating on Celgard Porous Matrices in the Presence of Carbon Dioxide under Pressure

It is shown that a chitosan coating can be deposited on the pore surface of Celgard polyolefin matrices from aqueous solutions of chitosan saturated with carbon dioxide under high pressure; i.e., when carbonic acid is formed. To ensure the stability of the coating, the initially hydrophobic matrices should be pretreated in the presence of peroxycarbonic acid, which is formed when the aqueous solution of hydrogen peroxide is saturated with carbon dioxide at a high pressure. The morphology of the deposited coating is studied by high-resolution microscopy. The introduced hydrophilic properties are evaluated from a change in the nature of the wetting of the matrix surface with water. It is found that the hydrophilized matrix modified with chitosan, in spite of a lower characteristic pore size, has ~1.5 times higher permeability for water than the initial matrix.

Floor- or Ceiling-Sliding for Chemically Active, Gyrotactic, Sedimenting Janus Particles.

Chemically active particles achieve motility without external forces and torques (“self-propulsion”) due to catalytic chemical reactions at their surfaces, which change the chemical composition of the surrounding solution (called “chemical field”) and induce hydrodynamic flow of the solution. By coupling the distortions of these fields back to its motion, a chemically active particle experiences an effective interaction with confining surfaces. This coupling can lead to a rich behavior, such as the occurrence of wall-bound steady states of “sliding”. Most active particles are density mismatched with the solution and, thus, tend to sediment. Moreover, the often employed Janus spheres, which consist of an inert core material decorated with a cap-like, thin layer of a catalyst, are gyrotactic (i.e., “bottom-heavy”). Whether or not they may exhibit sliding states at horizontal walls depends on the interplay between the active motion and the gravity-driven sedimentation and alignment, such as the gyrotactic tendency to align the axis along the gravity direction being overcome by a competing, activity-driven alignment with a different orientation. It is therefore important to understand and quantify the influence of these gravity-induced effects on the behavior of model chemically active particles moving in the vicinity of walls. For model gyrotactic, self-phoretic Janus particles, here we study theoretically the occurrence of sliding states at horizontal planar walls that are either below (“floor”) or above (“ceiling”) the particle. We construct “state diagrams” characterizing the occurrence of such states as a function of the sedimentation velocity and of the gyrotactic response of the particle, as well as of the phoretic mobility of the particle. We show that in certain cases sliding states may emerge simultaneously at both the ceiling and the floor, while the larger part of the experimentally relevant parameter space corresponds to particles that would exhibit sliding states only either at the floor or at the ceiling—or there are no sliding states at all. These predictions are critically compared with the results of previous experimental studies, as well as with our dedicated experiments carried out with Pt-coated, polystyrene-core, or silica-core Janus spheres immersed in aqueous hydrogen peroxide solutions.

Фармакологические свойства гемостатического препарата на основе неполной серебряной соли полиакриловой кислоты на модели паренхиматозного кровотечения

In this work, hemostatic properties of the Hemoblock preparation were studied using a model of parenchymal bleeding, in comparison with a 3% aqueous solution of hydrogen peroxide. The study was carried out on 30 white rats of both sexes weighing 180–200 g. under general anesthesia. Parenchymal bleeding was modeled by applying a wound on the left lobe of the liver with a scalpel. After the use of drugs, the wound was sutured in layers, tightly. An intradermal suture was applied to the skin. To assess the hemostatic effect, the time to stop bleeding was taken into account, as well as the presence or absence of relapse of parenchymal bleeding. As a result of studies, it was found that in animals after application of the studied drug, a complete stop of bleeding was observed after 120,7±4,3 seconds. Relapses of bleeding were absent. The wound surface was without signs of tissue damage. Stable hemostasis was achieved in 100% of cases.

Conformational dynamics of aqueous hydrogen peroxide from first principles molecular dynamics simulations.

We performed first principles molecular dynamics simulations of a relatively dilute aqueous hydrogen peroxide (H2O2) solution to examine its structural alterations and relevant dynamics upon solvation. The internal rotation of the OH groups about the O-O bond facilitates the flexible structure of H2O2. Structural calculations reveal dihedral angle fluctuations in the aqueous solution. Water molecules make stronger hydrogen bonds through the hydrogen atom of the solute than the oxygen atom leading to distinct hydrogen bonding configurations inside the first solvation shell. Time-dependent dihedral angle alterations result in conformational changes and the normalized dihedral angle distribution plot displays characteristic peaks at ∼100-120° and ∼230°, illustrating various conformational states. Within the simulation time, flexibility-induced interconversion of hydrogen peroxide gives rise to several cisoid and transoid conformers. In this study, we examine the relative population of the associated conformational states and the lifetime of the cisoid and transoid conformers from the torsion angle variations. We also determine the free energy landscape of the rotational isomerization process in H2O2 and explore two distinct energy barriers during such interconversion.

Explosive potential of energetic mixtures based on hydrogen peroxide

The explosion and detonation of energetic compositions based on hydrogen peroxide (H2O2, HP) is investigated. Fuels with different oxygen balance were considered in the mixture with HP/methanol, ethylene glycol, glycerine ethanol. Detonation performance at a wide range of reciprocal HP/fuel concentrations was examined. Heats of explosion at constant volume, detonation velocity, as well as volume of gaseous products of reaction were estimated in thermochemical evaluations. The modification of explosive properties of the high-energetic CHNO material by addition of hydrogen peroxide, was also investigated. To represent CHNO explosives, nitromethane was considered. In the performed analysis, aqueous solutions of hydrogen peroxide were considered with the aim of obtaining the appropriate fuel/HP/water ratios to predict potential explosive compositions.

Improvement of hydrophilicity and conductivity for graphite derivative by microwave irradiation with a hydrogen peroxide aqueous solution

The dispersibility improvement of graphite for water is achieved by using microwave irradiation in a hydrogen peroxide aqueous solution without catalyst and a strong oxidation reagent. The dispersibility is improved by introducing oxygen functional groups by chemical reaction graphite and hydroxyl radicals. However, the chemical reaction occurs only at the graphite edge which is different from other chemical methods with strong oxidant. As a result, the sample maintains a slightly expanded graphite structure. The obtained samples show higher conductivity than that of raw graphite in spite of a non-reduction. The conductivity increases with increasing microwave irradiation time and the maximum value was reached at about 140 S mm−1. This result is explained by high crystallinity and low defect density. Therefore, the microwave-irradiated graphite oxide is expected as a printable conductive carbon material.

Processes for Electrochemical Production of Electrolyte-free Hydrogen Peroxide

Hydrogen peroxide is the focus of growing attention for distributed manufacturing, reflecting its decentralized applications and shipping hazards. Two recent reports, one in Science by Wang and colleaugues and one in this issue of Joule by Surendranath, Hatton, and colleaugues, introduce innovative electrochemical methods to produce electrolyte-free aqueous solutions of hydrogen peroxide.

Evaluation of Influence on Etching Process of Sulfuric Acid-Hydrogen Peroxide Aqueous Solution by Impurity Addition

Evaluation of Influence on Etching Process of Sulfuric Acid-Hydrogen Peroxide Aqueous Solution by Impurity Addition

Conjugated processes of bulk aluminum and hydrogen combustion in water-oxygen mixtures

The article deals with the investigation of the combustion of aluminum bulk samples in water vapor, an aqueous solution of hydrogen peroxide (33.1 wt%), and water-oxygen mixture at uniform heating of the reactor (1 K/min) up to 773 K. It is revealed that the major portion of hydrogen peroxide is decomposed directly in aqueous solution. The resulting oxygen, as well as oxygen added to the water, provided oxidation of only a part of hydrogen (≈25%) released during the complete oxidation of aluminum by water. The time dependences of the reactants’ temperature and pressure, as well as the temperature corresponding to the onset of the H2 release were determined. The most intense oxidation of aluminum in water vapor was noted within the temperature range of 593–769 K, as well as in a hydrogen peroxide solution at 548–693 K, and in H2O/O2 mixture at 567–742 K. It is revealed that the oxidation of hydrogen with oxygen intensifies water oxidation of aluminum to a greater extent than it follows from the heat effects of H2 oxidation. As a result of oxidation, a loose powder of aluminum oxide nanoparticles was obtained.

Comparative Analysis of Separation Schemes of Reaction Mixtures of Epichlorohydrin Production in the Presence of Various Solvents

On the basis of a thermodynamic–topological analysis of phase equilibrium diagrams of reaction mixtures formed during the liquid phase epoxidation of allyl chloride with an aqueous solution of hydrogen peroxide in an organic solvent in the presence of a heterogeneous catalyst, two principal technological separation schemes are proposed. Two lower alcohols are considered as solvents: methanol and propanol-2. Both schemes are aimed at the isolation of all components in pure form and are based on the use of special separation methods: extractive rectification with dimethyl sulfoxide (separation of allyl chloride–methanol and propanol-2–water component pairs) and a combination of rectification and delamination (separation of binary allyl chloride–water and water mixtures–epichlorohydrin). The material balances of separation schemes for mixtures of a specific composition are calculated (one composition for both mixtures is considered). To determine the operation parameters of rectification columns (the number of separation stages, feed plate, and reflux ratio), a computational experiment is conducted using the Aspen Plus® software. Preference is given to parameters ensuring the production of all substances with a purity that meets GOST (State Standard) with minimum energy consumption. The separation scheme of the mixture with propanol-2 containing one column less is characterized by a lower total number of separation stages (by 32 theoretical plates) and lower (by 11%) energy consumption compared to the separation scheme of the mixture with methanol. In addition, the epoxidation reaction with an excess of propanol-2 (the alcohol concentration should be at least 68 wt %) can significantly simplify the allocation of the target product of epichlorohydrin, which is impossible for a system with methanol.

Method of preparation and biological activity of aqueous hydrogen peroxide solution

The possibility of increasing the concentration of hydrogen peroxide by using an electrolyte based on aqueous solutions of sodium sulfate or potassium sulfate salts is substantiated and implemented. Limit values of acidity and values of electrochemical potential of the activated aqueous solution are established. The obtained experimental confirmation of the possibility of the use of activated solution “Plasmolite” as a plant growth regulator.

Phenylalanine Photoinduced Fluorescence and Characterization of the Photoproducts by LC-MS.

Phenylalanine (Phe) is a direct precursor of tyrosine and several neurotransmitters. The accumulation of Phe in the brain generates serious and not recoverable pathologies in children. Early detection in newborns is fundamental to apply the appropriate therapy and avoid irreversible health problems. Although fluorescence is a sensitive and selective technique for the determination of amino acids, the fluorescent analysis of Phe is limited since it exhibits a very low fluorescence quantum yield; however, the fluorescence of Phe increases drastically under UV irradiation when a peroxide medium is used. The aim of this research was to analyze the effect of the UV-radiation on Phe aqueous-peroxide solutions and to study the influence of the chemical environment on the photoinducted fluorescence process. The nature and characteristics of the fluorescent photoproducts generated under off-line UV irradiation in hydrogen peroxide medium were achieved by high performance liquid chromatography (HPLC) using a spectrophotometer detector (DAD) coupled in series with a mass spectrometer (MS) or with a fast scan spectrofluorimetric detector (FSFD). Environmental characteristics such as pH, initial concentration of Phe, hydrogen peroxide amount and irradiation time were studied in order to establish their influence on the formation of each one of the photoproducts. As the formation of several highly fluorescent photoproducts has been confirmed, the possibility of designing a chromatographic system with a post-column on-line photoreactor is open. The measure of the total fluorescence signal generated from Phe at the optimized irradiation time, could be used for the determination, with high sensitivity, of the initial amount of Phe in aqueous media, such as human serum or environmental samples. These aspects are being studied at present. .

Photogeneration of reactive oxygen species over ultrafine TiO2 particles functionalized with rutin\u2013ligand induced sensitization and crystallization effects

Interaction of amorphous and crystalline TiO2 ultrafine particles (2–6 nm) with rutin results in the formation of colored nanomaterials of an excellent dispersity and enhanced colloidal stability in aqueous media. The FTIR and Raman spectra confirmed attachment of the rutin ligand via vicinal hydroxyl groups in a catechol-like fashion. The binding of rutin to amorphous TiO2 gives rise to spontaneous crystallization of the parent nanoparticles into hydrogen titanates (H2Ti3O7 and H2Ti12O25). Such structural transformations result in photosensitization toward visible light with enhanced efficiency of the charge separation and interfacial charge transfer processes, confirmed by detailed photoelectrochemical studies of the examined nanomaterials. The effectiveness of the photocatalytic ROS generation reactions was also strongly influenced by hydrogen peroxide, which plays a double role of a reactant prone to reduction and generation of hydroxyl radicals or a redox agent destroying the intra-band gap electronic states, suppressing thereby charge recombination. The photoinduced charge transfer processes lead to generation of various reactive oxygen species, which were detected by EPR using DMPO spin trap (HOO· detection) and in the reaction with terephthalic acid acting as a chemical scavenger (HO· detection). Complexation of TiO2 particles with rutin shifts the photogeneration of hydroperoxyl (HOO·) and hydroxyl (HO·) radicals toward visible light (λ > 400 nm). A triple effect of rutin attachment to titania was established. It consists in pronounced photosensitization, promotion of crystallization and enhancement of the colloidal stability of ultrafine titania particles. Environmental implications of these assets on the photoinduced redox reactions with hydrogen peroxide in aqueous solutions upon UV or visible light irradiation were also discussed.

NOx scrubbing with H2O2/HNO3 solutions achieved with a laboratory bubble contactor

In this work, the removal of dilute nitrogen oxides NOx from the gaseous effluents of Tunisian nitric acid plant by absorption into aqueous hydrogen peroxide solutions containing or not nitric acid was studied. All semi-continuous absorption tests were carried out at ambient conditions and at 40 Pa as NOx partial pressure. The effects of the gas flow rate, the initial H2O2 concentration and the presence of HNO3 on the NOx absorption efficiency (ANOx) were studied. The tests results revealed that ANOx increases with an increase in initial H2O2 concentration in the scrubbing liquid, but decreases with an increase of gas flow rate. Furthermore, the presence of nitric acid in the aqueous hydrogen peroxide solution has a positive effect on ANOx. These results confirmed that the removal of NOx liberated from the plants of the Tunisian Chemical Group (TCG) by absorption into H2O2 solution is a feasible and an effective solution.

Light-Driven ZnO Brush-Shaped Self-Propelled Micromachines for Nitroaromatic Explosives Decomposition.

Self-propelled micromachines have recently attracted lots of attention for environmental remediation. Developing a large-scale but template-free fabrication of self-propelled rod/tubular micro/nanomotors is very crucial but still challenging. Here, a new strategy based on vertically aligned ZnO arrays is employed for the large-scale and template-free fabrication of self-propelled ZnO-based micromotors with H2 O2 -free light-driven propulsion ability. Brush-shaped ZnO-based micromotors with different diameters and lengths are fully studied, which present a fast response to multicycles UV light on/off switches with different interval times (2/5 s) in pure water and slow directional motion in aqueous hydrogen peroxide solution in the absence of UV light. Light-induced electrophoretic and self-diffusiophoretic effects are responsible for these two different self-motion behaviors under different conditions, respectively. In addition, the pH of the media and the presence of H2 O2 show important effects on the motion behavior and microstructure of the ZnO-based micromotors. Finally, these novel ZnO-based brush-shaped micromotors are demonstrated in a proof-of-concept study on nitroaromatic explosive degradation, i.e., picric acid. This work opens a completely new avenue for the template-free fabrication of brush-shaped light-responsive micromotors on a large scale based on vertically aligned ZnO arrays.

Surface Charge-Reversible Tubular Micromotors for Extraction of Nucleic Acids in Microsystems.

Extraction of nucleic acids in microsystems is of significance for biomedical applications, but the current extraction methods generally require sophisticated microchannels and external equipment, hindering their practical applications. In this work, we have demonstrated a simple, versatile and efficient approach to extract nucleic acids in microsystems by developing cationic branched polyethyleneimine (PEI)-functionalized tubular micromotors. The as-developed tubular micromotors are fabricated by a two-step process combining the template-assisted electrodeposition and carbodiimide chemistry, and contain an inner catalytic Pt layer, a middle magnetic Ni layer and an outer cationic PEI layer. They exhibit autonomous bubble-propelled motion in aqueous hydrogen peroxide solutions, which can be guided by an external magnetic field, and the surface charges can be reversibly modulated by changing the pH value of the solution. Consequently, the as-developed tubular micromotors can selectively absorb nucleic acids from acidic solutions and desorb them into alkaline solutions, leading to the extraction of nucleic acids with high efficiency without external stirring. Furthermore, they can be operated in a microchannel chip without the aid of a pumping system. Our results indicate that this PEI-functionalized tubular micromotor platform provides a novel, simple and versatile microsystem nucleic acid extraction technology, holding considerable promise for important practical applications.

Processing of sanitary and household waste in biotechnical life support systems

In order to establish material loops in biotechnical life support systems (BTLSS), various types of organic waste generated within the system need to be effectively processed. A universal method should be developed to produce mineral fertilizers for the higher-plant compartment of the BTLSS regardless of the level of reduction of the organic compounds contained in the waste and the contents of mineral elements in it. A method of producing mineral fertilizers by organic waste oxidation in the hydrogen peroxide aqueous solution under application of an alternating current electric field is proposed as a possible approach. Methods of processing of human wastes and inedible plant biomass were discussed in previous studies. The present study demonstrates the approach to processing cotton waste and kitchen wastewater. The study describes processing of such wastes by using a supplementary oxidizer (nitric acid) and co-oxidation with other types of organic waste typically generated in the BTLSS. Recommendations are offered on using these approaches to process sanitary/household waste in the BTLSS.

Stable Immobilization of Enzymes in a Macro- and Mesoporous Silica Monolith.

Horseradish peroxidase isoenzyme C (HRP) and Engyodontium album proteinase K (proK) were immobilized inside macro- and mesoporous silica monoliths. Stable immobilization was achieved through simple noncovalent adsorption of conjugates, which were prepared from a polycationic, water-soluble second generation dendronized polymer (denpol) and the enzymes. Conjugates prepared from three denpols with the same type of repeating unit (r.u.), but different average lengths were compared. It was shown that there is no obvious advantage of using denpols with very long chains. Excellent results were achieved with denpols having on average 750 or 1000 r.u. The enzyme-loaded monoliths were tested as flow reactors. Comparison was made with microscopy glass coverslips onto which the conjugates were immobilized and with glass micropipettes containing adsorbed conjugates. High enzyme loading was achieved using the monoliths. Monoliths containing immobilized denpol–HRP conjugates exhibited good operational stability at 25 °C (for at least several hours), and good storage stability at 4 °C (at least for weeks) was demonstrated. Such HRP-containing monoliths were applied as continuous flow reactors for the quantitative determination of hydrogen peroxide in aqueous solution between 1 μM (34 ng/mL) and 50 μM (1.7 μg/mL). Although many methods for immobilizing enzymes on silica surfaces exist, there are only a few approaches with porous silica materials for the development of flow reactors. The work presented is a promising contribution to this field of research toward bioanalytical and biosynthetic applications.