scholarly journals Catalytic Properties of V–Ti–O Catalysts in the Oxidation and Ammoxidation of o-xylene, Acenaphthene and β-picoline

2016 ◽  
Vol 5 (4) ◽  
pp. 267 ◽  
Author(s):  
L.I. Saurambaeva ◽  
D.Kh. Sembaev
Keyword(s):  
Solid Solution ◽  
Catalytic Activity ◽  
Titanium Oxide ◽  
Organic Compounds ◽  
Catalytic Properties ◽  
The Other ◽  
V2o5 Content ◽  
Oxidation Of Organic Compounds ◽  
Maximum Conversion ◽  
Vanadium Titanium

<p>Catalytic properties of vanadium–titanium oxide catalysts in the oxidation and ammoxidation of o-xylene, acenaphthene and β-picoline have been studied. Methods of preparation of catalysts with varying amounts contents of V<sub>2</sub>O<sub>5</sub> have been described. It has been shown that activity and selectivity in oxidation of organic compounds of different nature depends on the V2O5 content and the ratio of the oxides in the solid solution. Maximum selectivity in relation to phthalic and naphthalic anhydrides, naphthalimide and nitrile of nicotinic acid with the maximum conversion is observed with the catalysts having 4–6 wt.% of V<sub>2</sub>O<sub>5</sub>. Catalysts with other compositions showed lesser conversion of the initial substance. A catalyst, representing VO<sub>2</sub>–TiO<sub>2</sub> solid solution, exhibits the least activity and selectivity among the tested samples for oxidation of o-xylene and ammoxidation of β-picoline. For oxidation and ammoxidation of acenaphthene, the least activity and selectivity are exhibited by a catalyst, containing alongside with the solid solution no more than 3% by weight of V<sub>2</sub>O<sub>5</sub>. Catalysts with an equal V<sub>2</sub>O<sub>5</sub> amount, but differing one from the other by a composition of a solid solution, display different catalytic activity in o-xylene oxidation and β-picoline ammoxidation. Enrichment of solid solution with VO<sub>2</sub> or a decrease in the amount of the latter in the content decrease activity and selectivity of a catalyst.</p>

Study of Structural and Catalytic Properties of Pt/WOх/ZrO₂, Modified by Lanthanum Cations

2020 ◽  
pp. 133-141
Author(s):  
Svetlana A. Naumova ◽  
Anastasia V. Obukhova ◽  
Ludmila I. Kuznetsova
Keyword(s):  
Solid Solution ◽  
Catalytic Activity ◽  
Phase Composition ◽  
Structural Properties ◽  
Catalytic Properties ◽  
Surface Layers ◽  
Tetragonal Modification ◽  
Nanocrystalline Zirconia ◽  
Positive Effect

The effect of the addition of La3+ cations on the structural properties of Pt/WOх/ZrO₂ catalysts and the characteristics of catalytic activity in the process of hydroisomerization of n-heptane and benzene mixture was studied. The phase composition of the catalysts is represented by a solid solution of lanthanum cations in nanocrystalline zirconia of tetragonal modification with localization of lanthanum in the surface layers predominantly. The positive effect of La3+ additives on the selectivity and yield of isomerized products was shown

Stability and catalytic properties of μ-oxo and μ-nitrido dimeric iron tetrasulfophthalocyanines in the oxidation of Orange II by tert-butylhydroperoxide

2014 ◽  
Vol 18 (07) ◽  
pp. 604-613 ◽  
Author(s):  
Anna S. Makarova ◽  
Evgeny V. Kudrik ◽  
Sergei V. Makarov ◽  
Oskar I. Koifman
Keyword(s):  
Catalytic Activity ◽  
Aqueous Solutions ◽  
Catalytic Oxidation ◽  
Organic Compounds ◽  
High Stability ◽  
Catalytic Properties ◽  
Orange Ii ◽  
Tert Butylhydroperoxide ◽  
Good Catalytic Activity ◽  
Very High

A study of catalytic activity of μ-nitrido- and μ-oxo-dimeric iron tetrasulfophthalocyanines in the oxidation of Orange II by tert-butylhydroperoxide in aqueous solutions has been performed. It is shown that though in one catalytic cycle activity of μ-oxo-dimer is higher, stability of this complex in oxidative conditions is poor. μ-nitrido-dimer combines relatively good catalytic activity with very high stability in the presence of tert-butylhydroperoxide. The mechanisms of oxidative decomposition of dimers and catalytic oxidation of Orange II have been proposed on the base of kinetic results. The products of catalytic processes are shown to be bio-degradable non-toxic small organic compounds.

scholarly journals Mechanochemical and sonochemical syntheses of new nanocomposites

2021 ◽  
pp. 79-92
Author(s):  
Valery O. Zazhigalov ◽  
◽  
Olena V. Sachuk ◽  
Olena A. Diyuk ◽  
Iryna V. Bacherikova ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Titanium Oxide ◽  
Organic Compounds ◽  
Tin Oxide ◽  
Visible Light Irradiation ◽  
Amorphous Layer ◽  
Calcium Titanate ◽  
Oxide Surface ◽  
Compound Formation ◽  
First Time

For the first time the possibility of the complex nanodispersed compound formation at mechanochemical and sonochemical treatment of the initial compounds mixture was shown. Mechochemical treatment of the mixture of molybdenum oxide and bismuth nitrate permits to obtain of bismuth molybdate in form of nanoparticles, in the same time the treatment of mixture of titanium oxide and calcium hydroxide leads to formation of calcium titanate in form of nanoprisms. It was shown that mechanochemical treatment of the mixture of titanium oxide and tin oxide leads to formation of titanium oxide amorphous layer on tin oxide surface. The mechanism of nanodispersed zinc molybdate formation at sonochemical treatment of initial oxides was established. It was shown that nanocomposites synthesized by these methods demonstrate the higher catalytic activity in organic compounds neutralization processes in water solutions at visible light irradiation and in the process of bioethanol selective oxidation to acetaldehyde and hydrogen in comparison with known analogous catalysts synthesized by traditional methods.

Removal of Trace Metals From Wastewater by Activated Carbon

1973 ◽  
Vol 8 (1) ◽  
pp. 110-121
Author(s):  
A. Netzer ◽  
J.D. Norman
Keyword(s):  
Activated Carbon ◽  
Trace Metals ◽  
Organic Compounds ◽  
The Other ◽  
Published Data ◽  
Ph Adjustment ◽  
Nickel Silver ◽  
Ph Range ◽  
Carbon Treatment ◽  
Cobalt Copper

Abstract The merits of activated carbon for removal of organic compounds from wastewater have been well documented in the literature. On the other hand there is a lack of published data on the use of activated carbon for the removal of trace metals from wastewater. Experiments were designed to assess the possibility that activated carbon treatment would remove aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, silver and zinc from wastewater. All metals studied were tested over the pH range 3-11. Greater than 99.5% removal was achieved by pH adjustment and activated carbon treatment for most of the metals tested.

Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Nickel Oxide ◽  
Catalytic Properties ◽  
Cadmium Oxide ◽  
Chemisorb Oxygen ◽  
Composition Region ◽  
Chemisorbed Oxygen ◽  
Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Flower-Shaped C-Dots/Co3O4{111} Constructed with Dual-Reaction Centers for Enhancement of Fenton-Like Reaction Activity and Peroxymonosulfate Conversion to Sulfate Radical

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 135
Author(s):  
Zhibin Wen ◽  
Qianqian Zhu ◽  
Jiali Zhou ◽  
Shudi Zhao ◽  
Jinnan Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Centers ◽  
Organic Radicals ◽  
The Other ◽  
High Catalytic Activity ◽  
High Adsorption ◽  
High Turnover

Novel flower-shaped C-dots/Co3O4{111} with dual-reaction centers were constructed to improve the Fenton-like reaction activity and peroxymonosulfate (PMS) conversion to sulfate radicals. Due to the exposure of a high surface area and Co3O4{111} facets, flower-shaped C-dots/Co3O4{111} could provide more Co(II) for PMS activation than traditional spherical Co3O4{110}. Meanwhile, PMS was preferred for adsorption on Co3O4{111} facets because of a high adsorption energy and thereby facilitated the electron transfer from Co(II) to PMS. More importantly, the Co–O–C linkage between C-dots and Co3O4{111} induced the formation of the dual-reaction center, which promoted the production of reactive organic radicals (R•). PMS could be directly reduced to SO4−• by R• over C-dots. On the other hand, electron transferred from R• to Co via Co–O–C linkage could accelerate the redox of Co(II)/(III), avoiding the invalid decomposition of PMS. Thus, C-dots doped on Co3O4{111} improved the PMS conversion rate to SO4−• over the single active site, resulting in high turnover numbers (TONs). In addition, TPR analysis indicated that the optimal content of C-dots doped on Co3O4{111} is 2.5%. More than 99% of antibiotics and dyes were degraded over C-dots/Co3O4{111} within 10 min. Even after six cycles, C-dots/Co3O4{111} still remained a high catalytic activity.

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