Decomposition of hydrogen peroxide on nickel-silver two-component catalyst

1984 ◽  
Vol 49 (10) ◽  
pp. 2222-2230 ◽  
Author(s):  
Viliam Múčka ◽  
Rostislav Silber
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Properties ◽  
Silver Ions ◽  
Surface Concentration ◽  
Chloride Ions ◽  
Nickel Silver ◽  
Silver Catalysts ◽  
Physico Chemical ◽  
Low Degree ◽  
Defective Crystal

The catalytic and physico-chemical properties of low-temperature nickel-silver catalysts with nickel oxide concentrations up to 43.8% (m/m) are examined via decomposition of hydrogen peroxide in aqueous solution. The mixed catalysts prepared at 250°C are composed of partly decomposed silver carbonate or oxide and nickel carbonate or hydroxide decomposed to a low degree only and exhibiting a very defective crystal structure. The activity of these catalysts is determined by the surface concentration of silver ions, which is affected by the nickel component present. The latter also contributes to the thermal stability of the catalytic centres of the silver component, viz. the Ag+ ions. The concentration of these ions varies with the temperature of the catalyst treatment, the activity varies qualitatively in the same manner, and the system approaches the Ag-NiO composition. The catalytic centres are very susceptible to poisoning by chloride ions. A previous exposition of the catalyst to a gamma dose of 10 kGy from a 60Co source has no measurable effect on the physico-chemical properties of the system.

scholarly journals ONE-POT-TWO-STEP SYNTHESIS OF BIOLUBRICANT BASE STOCK FROM RUBBER SEED OIL

2020 ◽  
Vol 45 (5) ◽  
Author(s):  
G.O . Madojemu ◽  
E.A. Elimian ◽  
M.C. Ejimadu ◽  
C.O. Okieimen ◽  
F.E. Okieimen
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Response Surface ◽  
Seed Oil ◽  
Chemical Properties ◽  
Base Stock ◽  
One Pot ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Physico Chemical

Biolubricant base stock was synthesized in this work from rubber seed oil in a one-pot-two-step process of epoxidation and hydroxylation. Rubber seed oil was extracted using a Soxhlet apparatus. The in situ epoxidation of the rubber seed oil with peracid (hydrogen peroxide and acetic acid) was analysed and optimized considering three process variables with their range of values given as temperature of 35-50 , time of 60-180 mins and mole ratio of hydrogen peroxide to acetic acid of 1:0.25-1:1 by applying the central composite design of response surface methodology. The ring opening reaction (hydroxylation) of the epoxide to polyhydroxylated oil (lubricant basestock) with ethanol was carried out using the optimum conditions obtained from the epoxidation process. The rubber seed oil, epoxide and lubricant basestock were characterized in terms of physico-chemical properties using standard methods and in terms of functional groups using Fourier Transform Infrared (FTIR) spectroscopy. Maximum epoxide content of 4.85% and maximum conversion of 71% of rubber seed oil to epoxide was achieved at a temperature of 50􀀀 , reaction time of 180 mins and 1: 0.39 mol/mol of hydrogen peroxide to acetic acid. The predicted values of the epoxidation process reasonably agreed with the experimental ones and model R-squared value of about 95% showed that response surface method can reasonably predict the epoxidation process using a quadratic polynomial model. There was 75% conversion of the epoxide to polyhydroxylated oil (biolubricant basestock), which represents a very high yield. The formation of epoxides and polyhydroxylated oil lead to modification (improvement) in the properties of rubber seed oil as confirmed by the physico-chemical properties and FTIR spectra analysis of the oil, epoxide and lubricant basestock. The study showed that chemical derivatives of rubber seed oils are an attractive, renewable, and ecofriendly alternative to mineral oils for lubricant formulations.

scholarly journals Sensors for analysis of hydrogen peroxide

2020 ◽  
Vol 3 ◽  
pp. 169-174
Author(s):  
Lala Gurbanova ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Sensors ◽  
Chemical Properties ◽  
Electrochemical System ◽  
Physico Chemical ◽  
New Type

The physico-chemical properties of new type catalase sensors, the so-called biomimetic sensors modulating some of catalase biosensor functions were investigated. These sensors have technological advantages ever their biological analogs due to the properties usually attributed to chemical sensors. The development electrochemical system stands in between bio- and chemical sensors.

scholarly journals OBTAINING AND PHYSICO-CHEMICAL PROPERTIES OF MATERIALS BASED ON EXPANDED VERMICULITES OF VARIOUS COMPOSITIONS

2018 ◽  
Vol 61 (6) ◽  
pp. 76
Author(s):  
Alexander V. Kalashnik ◽  
Sergey G. Ionov
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Properties ◽  
Decomposition Reaction ◽  
Chemical Compositions ◽  
Thermal Treatments ◽  
X Ray ◽  
Expanded Vermiculite ◽  
Physico Chemical ◽  
Developed Surface ◽  
Properties Of Materials

Optimal conditions for chemical and thermal treatments of natural vermiculites from various deposits were determined. The aim of obtaining expanded vermiculites with a minimum bulk density was pursued. Optimum temperature for producing thermal expanded vermiculites was 700 °C. According to scanning electron microscopy chemical expanded vermiculite has more developed surface in comparison with thermal expanded vermiculite. Chemical composition of natural vermiculites of various deposits and expanded vermiculites based on them was defined by X-ray fluorescence. It was shown that the vermiculite of the Tatar deposit contains a large amount of iron distributed over the surface. As a result, the vermiculite from Tatarstan can not be modified by hydrogen peroxide because of the active decomposition reaction of hydrogen peroxide on the surface of vermiculite. It was established that the chemical compositions of natural vermiculites as well as expanded vermiculites based on them do not differ. According to Mössbauer spectroscopy the ratio Fe(II)/Fe(III) in natural vermiculate was 1:4 and in thermal expanded vermiculite was 1:8. It should be noted that chemical expanded vermiculate contains only Fe(III). According to X-ray phase analysis the phase composition of natural vermiculite changes at 350 °C. It was defined that natural vermiculite and thermal expanded vermiculite after adsorption of moisture from the air have the same position of the X-ray maximum. When natural vermiculite was heated two areas of water loss were observed by the thermogravimetric analysis. The anisotropy of tensile strength for samples of the same density taken along and across the rolling axis of vermiculite foil obtained by pressing expanded vermiculite without a binder was described. The thermal conductivity coefficient of vermiculite foil was determined. This makes it possible to use the material as heat shield and fire protector.Forcitation:Kalashnik A.V., Ionov S.G. Obtaining and physico-chemical properties of materials based on expanded vermiculites of various compositions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 76-82

Hydrogen peroxide decomposition on a non-irradiated and gamma pre-irradiated NiO-U3O8 catalyst

1981 ◽  
Vol 46 (8) ◽  
pp. 1886-1897 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Hydrogen Peroxide ◽  
Gamma Rays ◽  
Catalytic Properties ◽  
Chemical Properties ◽  
Oxidation States ◽  
Hydrogen Peroxide Decomposition ◽  
Physico Chemical ◽  
Peroxide Decomposition ◽  
Charge Interaction ◽  
Observed Behaviour

This paper deals with some physico-chemical properties of a two component catalyst NiO-U3O8, prepared with varying ratio of both components. Special interest was given to the catalytic properties - tested by decomposition of aqueous solution of hydrogen peroxide. The study presented evidence of mutual charge interaction between both components of the catalyst. This enables one to explain the observed behaviour of the studied system on the basis of the principle of bivalent sites. A pre-irradiation of a catalyst by gamma rays leads to significant increase of the oxidation states of both catalyst components.

scholarly journals Investigation of the Physico-Chemical Properties of the Products Obtained after Mixed Organic-Inorganic Leaching of Spent Li-Ion Batteries

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6732
Author(s):  
Weronika Urbańska ◽  
Magdalena Osial
Keyword(s):  
Hydrogen Peroxide ◽  
Glutaric Acid ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Li Ion Batteries ◽  
X Ray Diffraction ◽  
Widespread Application ◽  
Portable Electronics ◽  
Physico Chemical ◽  
Li Ion

Lithium-ion batteries are currently one of the most important mobile energy storage units for portable electronics such as laptops, tablets, smartphones, etc. Their widespread application leads to the generation of large amounts of waste, so their recycling plays an important role in environmental policy. In this work, the process of leaching with sulfuric acid for the recovery of metals from spent Li-ion batteries in the presence of glutaric acid and hydrogen peroxide as reducing agents is presented. Experimental results indicate that glutaric-acid application improves the leaching performance compared to the use of just hydrogen peroxide under the same conditions. Obtained samples of leaching residues after mixed inorganic-organic leaching were characterized with Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction.

scholarly journals Chemical Denudation in a Geoecosystem in Acid Immision Conditions / Denudacja Chemiczna W Geoekosystemie W Warunkach Kwaśnej Imisji

2013 ◽  
Vol 20 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Rafał Kozłowski ◽  
Marek Jóźwiak
Keyword(s):  
Mineral Soil ◽  
Atmospheric Precipitation ◽  
Chemical Properties ◽  
Chloride Ions ◽  
Acid Neutralizing Capacity ◽  
Soil Horizon ◽  
Exchange Processes ◽  
Physico Chemical ◽  
Neutralizing Capacity ◽  
Substantial Drop

Abstract There is an analysis of the physico-chemical properties and the chemical composition of precipitation in a forest geoecosystem in acid immision conditions. The data used in the analysis was collected between 2000 and 2010. In that period, a drop in the immision scale of S-SO2 in the atmospheric air had been observed, which consequently was one of the reasons for a drop in the precipitation acidity. The conclusion was that rainwater, after penetrating treetops and trunks, undergoes a significant transformation whose intensity depends on species composition of the forest stand. Statistically relevant differences were found in coniferous stands, in which a substantial drop in pH was noted, in addition to an increase in the load of components accumulated in the soil in relation to atmospheric precipitation. The calculated indicators of the eco-chemical state of waters (Ma%) have revealed that throughfall waters in coniferous stands and fir and beech stemflow contain significant amounts of aluminium, manganese, iron and hydrogen ions in the sum of cations. Also the indicator of acid-neutralizing capacity (ANCaq) shows that these waters are more enriched with sulfate, nitrate and chloride ions than bulk precipitation. The recorded variation eventuates from processes related to dry and humid deposition, as well as ion-exchange processes occurring within the stand. The obtained results point to an intensification of chemical denudation within the trunks, triggering disadvantageous changes in both biotic and abiotic part of the ecosystem. The effects of the increased inflow of souring agents to the soil through stemflow are significant acidification of the top mineral soil horizon and an increase in the hydrolytic acidity.

scholarly journals Entrapment of Citrus limon var. pompia Essential Oil or Pure Citral in Liposomes Tailored as Mouthwash for the Treatment of Oral Cavity Diseases

2020 ◽  
Vol 13 (9) ◽  
pp. 216
Author(s):  
Lucia Palmas ◽  
Matteo Aroffu ◽  
Giacomo L. Petretto ◽  
Elvira Escribano-Ferrer ◽  
Octavio Díez-Sales ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Essential Oil ◽  
Chemical Properties ◽  
Citrus Limon ◽  
Cryogenic Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Skin Repair ◽  
Physico Chemical ◽  
Cariogenic Bacterium

This work aimed at developing a mouthwash based on liposomes loading Citrus limon var. pompia essential oil or citral to treat oropharyngeal diseases. Vesicles were prepared by dispersing phosphatidylcholine and pompia essential oil or citral at increasing amounts (12, 25 and 50 mg/mL) in water. Transparent vesicle dispersions were obtained by direct sonication avoiding the use of organic solvents. Cryogenic transmission electron microscopy (cryo-TEM) confirmed the formation of unilamellar, spherical and regularly shaped vesicles. Essential oil and citral loaded liposomes were small in size (~110 and ~100 nm, respectively) and negatively charged. Liposomes, especially those loading citral, were highly stable as their physico-chemical properties did not change during storage. The formulations were highly biocompatible against keratinocytes, were able to counteract the damages induced in cells by using hydrogen peroxide, and able to increase the rate of skin repair. In addition, liposomes loading citral at higher concentrations inhibited the proliferation of cariogenic bacterium.

scholarly journals Physico-chemical properties of Silicea terra 200cH and activity on macrophages in vitro

2021 ◽  
Vol 18 (02) ◽  
pp. 07-07
Author(s):  
Sandra Pinto ◽  
Michelle Sanchez Aguiar ◽  
Elizabeth Hurtado ◽  
Leoni Villano Bonamin
Keyword(s):  
Electrical Conductivity ◽  
Hydrogen Peroxide ◽  
Chronic Wounds ◽  
Pure Water ◽  
Chemical Properties ◽  
Raw 264.7 Macrophages ◽  
Macrophage Activity ◽  
Micro Particles ◽  
Physico Chemical

Introduction Silicea terra 200cH can modulate macrophage activity in mice inducing resolution of chronic wounds, whose mechanisms are unknown. Herein, we describe the relation between the activity of Silicea terra 200cH in vitro, on macrophages infected with Calmette-Guérin Bacilli (BCG) - a microorganism involved in chronic granuloma lesions - and physico-chemical properties of the remedy. Objective Establish the relation between physico-chemical properties and biological activity of Silicea terra 200cH in vitro. Methods BCG-infected RAW 264.7 macrophages were analyzed considering their capacity of bacilli internalization, lysosome activity, hydrogen peroxide (H2O2) and cytokines production, using a CBA (BD) kit. The vehicle (succussed water) was used as control. The electrical conductivity and the presence of micro particles in the remedy were also studied. Results Silicea terra 200cH showed significant reduction of hydrogen peroxide production (p?0.001), higher lysosome activity (p?0.001) and increase of IL-10 production (p?0.05), an anti-inflammatory cytokine, in relation to the control. The electrical conductivity of Silicea terra 200cH was statistically higher in relation to pure water (p

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