Radiation catalytical effects in the pre-irradiated and thermally treated catalyst BASF K-3-10

1987 ◽  
Vol 52 (10) ◽  
pp. 2383-2391 ◽  
Author(s):  
Alois Motl
Keyword(s):  
Catalyst Activity ◽  
Dose Dependence ◽  
Nitrogen Atmosphere ◽  
Beta Radiation ◽  
Fast Neutrons ◽  
Strong Decrease ◽  
Γ Radiation ◽  
Different Types ◽  
Total Disappearance ◽  
Thermal Stability Of

The effects of various thermal treatment methods on the radiation catalytical effects, induced by the pre-irradiation of the BASF K-3-10 catalyst by the γ- or β-radiation or by fast neutrons, were investigated. It has been found that the calcination of the irradiated non-reduced catalyst results in a strong decrease or even in total disappearance of the final radiation catalytical effects; however, at the same time the catalytical activity of the unirradiated catalyst was found to increase. The calcination of the catalysts in nitrogen atmosphere after reduction led also to a substantial decrease of the resulting positive radiation catalytical effects and exceeding a certain calcination temperature resulted in the decrease even of the unirradiated catalyst activity. It could be concluded that the calcination in nitrogen of the reduced irradiated samples decreases the radiation catalytical effects less than the calcination on air of the non-reduced irradiated samples. In both cases a different thermal stability of effects induced by different types of the ionizing radiation has been observed and it has been found that it increases in the sequence beta radiation – gamma radiation – fast neutrons. The investigation of the γ radiation dose dependence of the radiation catalytical effect on the catlyst calcinated before irradiation under the access of air showed that the final radiation catalytical effects are lower than those observed in the case of similarly irradiated but non-calcinated samples. At the same time the dose dependence of the effect has the same character in both cases.

Effect of the ionizing radiation on the catalytic activity of the BASF K-3-10 catalyst in the low-temperature conversion of carbon monoxide by water vapour. Catalytic activity of the pre-irradiated catalyst

1986 ◽  
Vol 51 (2) ◽  
pp. 279-287 ◽  
Author(s):  
Alois Motl
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Ionizing Radiation ◽  
Water Vapour ◽  
Effective Activation Energy ◽  
Absorbed Dose ◽  
Beta Radiation ◽  
Fast Neutrons ◽  
Different Types

The catalytic activity of the BASF K-3-10 catalyst with regard to the low-temperature conversion of carbon monoxide by water vapour and its changes after irradiation of the contact area by gamma or beta radiation or by fast neutrons has been investigated. The irradiated samples exhibit a moderately or even substantially higher catalytic activity in comparison with the non-irradiated catalyst, the change being dependent on the absorbed dose; moreover, the effective activation energy of the reaction increases, too. Important differences in the action of different types of the ionizing radiation used have been observed and their probable explanation is offered. In course of these experiments the catalysts were analyzed and the specific surface of the catalyst was measured at various stages of their history. It has been found that at all stages the specific surfaces of the irradiated catalyst are equal to the respective specific surfaces of the non-irradiated contacts.

Reducing the Ecotoxicity of Pesticide Polluted Waters by Electrochemical Methods

2019 ◽  
Vol 70 (5) ◽  
pp. 1574-1578
Author(s):  
Cristian Neamtu ◽  
Bogdan Tutunaru ◽  
Adriana Samide ◽  
Alexandru Popescu
Keyword(s):  
Nitrogen Atmosphere ◽  
Constant Current ◽  
Polluted Water ◽  
Gaseous Nitrogen ◽  
Constant Current Density ◽  
Electrochemical Approach ◽  
Saline Waters ◽  
Thermal Combustion ◽  
Polluted Waters ◽  
Thermal Stability Of

Electrochlorination constitutes an electrochemical approach for the treatment of pesticide-containing wastewaters. This study evaluated the electrochemical and thermal stability of four pesticides and the efficiency of electrochlorination to remove and detoxify the simulated polluted water with: Acetamiprid, Emamectin, Imidacloprid and Propineb. This study reports the experimental results obtained by cyclic voltammetry and electrolysis at constant current density in association with UV-Vis spectrophotometry. In saline waters this pesticides are electrochemical active and anodic peaks are registered in the corresponding voltammograms. After thermal combustion, in a gaseous nitrogen atmosphere, a residue ranging from 15 to 45 % is observed at 500 �C.

Non-Isothermal Decomposition Kinetic of Polypropylene/Hydrotalcite Composite

2019 ◽  
Vol 19 (11) ◽  
pp. 7493-7501 ◽  
Author(s):  
Sheng Xu ◽  
Min Zhang ◽  
Siyu Li ◽  
Moyu Yi ◽  
Shigen Shen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Nitrogen Atmosphere ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Kinetic And Thermodynamic Parameters ◽  
Málek Method ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Thermal Stability Of

P3O5-10 pillared Mg/Al hydrotalcite (HTs) as a functional fire-retarding filler was successfully prepared by impregnation-reconstruction, where the HTs was used to prepare polypropylene (PP) and HTs composite (PP/HTs). Thermal decomposition was crucial for correctly identifying the thermal behavior for the PP/HTs, and studied using thermogravimetry (TG) at different heating rates. Based on single TG curves and Málek method, as well as 41 mechanism functions, the thermal decompositions of the PP/HTs composite and PP in nitrogen atmosphere were studied under non-isothermal conditions. The mechanism functions of the thermal decomposition reactions for the PP/HTs composite and PP were separately “chemical reaction F3” and “phase boundary reaction R2,” which were also in good agreement with corresponding experimental data. It was found that the addition of the HTs increased the apparent activation energy Ea of the PP/HTs comparing to the PP, which improved the thermal stability of the polypropylene. A difference in the set of kinetic and thermodynamic parameters was also observed between the PP/HTs and PP, particularly with respect to lower ΔS≠ value assigned to higher thermal stability of the PP/HTs composite.

scholarly journals Morphological and Behavioral Effects in Zebrafish Embryos after Exposure to Smoke Dyes

Toxics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Kimberly T. To ◽  
Lindsey St. Mary ◽  
Allyson H. Wooley ◽  
Mitchell S. Wilbanks ◽  
Anthony J. Bednar ◽  
...  
Keyword(s):  
Dose Dependence ◽  
Behavioral Effects ◽  
Zebrafish Embryos ◽  
Comprehensive Understanding ◽  
Anthraquinone Dyes ◽  
Locomotor Movement ◽  
Different Types ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Significant Mortality

Solvent Violet 47 (SV47) and Disperse Blue 14 (DB14) are two anthraquinone dyes that were previously used in different formulations for the production of violet-colored smoke. Both dyes have shown potential for toxicity; however, there is no comprehensive understanding of their effects. Zebrafish embryos were exposed to SV47 or DB14 from 6 to 120 h post fertilization (hpf) to assess the dyes’ potential adverse effects on developing embryos. The potential ability of both dyes to cross the blood–brain barrier was also assessed. At concentrations between 0.55 and 5.23 mg/L, SV47 showed a dose-dependent increase in mortality, jaw malformation, axis curvature, and edemas. At concentrations between 0.15 and 7.54 mg/L, DB14 did not have this same dose-dependence but had similar morphological outcomes at the highest doses. Nevertheless, while SV47 showed significant mortality from 4.20 mg/L, there was no significant mortality on embryos exposed to DB14. Regardless, decreased locomotor movement was observed at all concentrations of DB14, suggesting an adverse neurodevelopmental effect. Overall, our results showed that at similar concentrations, SV47 and DB14 caused different types of phenotypic effects in zebrafish embryos.

Effect of the ionizing radiation on the catalytic activity of the BASF K-3-10 catalyst in the low-temperature conversion of carbon monoxide by water vapour. Stability of the radiation catalytic effects

1986 ◽  
Vol 51 (8) ◽  
pp. 1571-1578 ◽  
Author(s):  
Alois Motl
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Effect ◽  
Catalytic Properties ◽  
Beta Radiation ◽  
Fast Neutrons ◽  
Time Interval ◽  
The Stability ◽  
Catalytic Effects

The radiation catalytic properties of the BASF K-3-10 catalyst were studied, namely the dependence of these effects on the time interval between the catalyst irradiation and the reaction itself and also on the length of the catalyst use. The catalytic effects decrease exponentially with the interval between the irradiation and the reaction if the catalyst is kept in the presence of air. The stability of effects induced by various types of radiations increases in the sequence beta radiation - gamma radiation - fast neutrons. The radiation catalytic effect stability in the reaction increases in the same sequence.

scholarly journals Causes and timing of future biosphere extinctions

2006 ◽  
Vol 3 (1) ◽  
pp. 85-92 ◽  
Author(s):  
S. Franck ◽  
C. Bounama ◽  
W. von Bloh
Keyword(s):  
Global Carbon Cycle ◽  
Temperature Tolerance ◽  
Cambrian Explosion ◽  
Strong Decrease ◽  
The Earth ◽  
Reverse Sequence ◽  
Different Types ◽  
Global Surface ◽  
Global Carbon

Abstract. We present a minimal model for the global carbon cycle of the Earth containing the reservoirs mantle, ocean floor, continental crust, biosphere, and the kerogen, as well as the combined ocean and atmosphere reservoir. The model is specified by introducing three different types of biosphere: procaryotes, eucaryotes, and complex multicellular life. During the entire existence of the biosphere procaryotes are always present. 2 Gyr ago eucaryotic life first appears. The emergence of complex multicellular life is connected with an explosive increase in biomass and a strong decrease in Cambrian global surface temperature at about 0.54 Gyr ago. In the long-term future the three types of biosphere will die out in reverse sequence of their appearance. We show that there is no evidence for an implosion-like extinction in contrast to the Cambrian explosion. In dependence of their temperature tolerance complex multicellular life and eucaryotes become extinct in about 0.8–1.2 Gyr and 1.3–1.5 Gyr, respectively. The ultimate life span of the biosphere is defined by the extinction of procaryotes in about 1.6 Gyr.

Dose Dependence of Hypermethylation of Gene Promoters in Blood Leukocytes in Humans Occupationally Exposed to External γ-Radiation

2019 ◽  
Vol 46 (11) ◽  
pp. 1489-1495
Author(s):  
N. S. Kuzmina ◽  
N. Sh. Lapteva ◽  
G. G. Rusinova ◽  
T. V. Azizova ◽  
N. S. Vyazovskaya ◽  
...  
Keyword(s):  
Dose Dependence ◽  
Gene Promoters ◽  
Blood Leukocytes ◽  
Γ Radiation ◽  
Occupationally Exposed

Investigation on Thermal Stability of Geopolymer Based Zeolite in Fire Case Study

2020 ◽  
Vol 1009 ◽  
pp. 31-36
Author(s):  
Kanokwan Kanyalert ◽  
Prinya Chindaprasirt ◽  
Duangkanok Tanangteerapong
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Alkali Activation ◽  
Different Types ◽  
Temperature Exposure ◽  
In Fire ◽  
Thermal Stability Of

This work aims to reveal the effects of zeolite on properties of fly ash based geopolymer under high temperature at 300 °C, 600 °C and 900 °C. The specimens were prepared by alkali activation of fly ash, which was partially replaced by two different types of zeolite at 10%, 20% and 30% by weight. The specimens were analyzed for the maximum compressive strength, weight loss percentage, XRD and SEM. The results highlighted that the percentage of weight loss increased with the ratio of zeolite replacement. The compressive strength of geopolymer with synthetic zeolite and natural zeolite at 7, 28, 60 days were similar. The high-temperature exposure resulted in the reduction in compressive strength in all proportions. At the same temperature, compressive strength of all specimens were not significantly different.

PP/Wasted PET Fabric Composites Compatibilized by two Different Methods: Mechanical Properties, Morphology and Thermal Stability

2012 ◽  
Vol 476-478 ◽  
pp. 730-733
Author(s):  
Zhi Dan Lin ◽  
Zi Xian Guan ◽  
Neng Sheng Liu ◽  
Zheng Jun Li
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Maleic Anhydride ◽  
Injection Molding ◽  
Methyl Methacrylate ◽  
Pet Fabric ◽  
Fabric Composites ◽  
Different Types ◽  
Thermal Stability Of

The composites of polypropylene (PP) and wasted PET fabric (WF) were prepared by extrusion blending and injection molding, and then, the interface of the composites was modified by two different types of compatibilizers, i.e., maleic anhydride grafted PP (PP-g-MA) and the mixture of methyl methacrylate (MMA) and styrene (St). The mechanical properties, morphology and thermal stability of these composites were studied.

scholarly journals The Impact of CeO2 Loading on the Activity and Stability of PdO/γ-AlOOH/γ-Al2O3 Monolith Catalysts for CH4 Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 557
Author(s):  
Hamad AlMohamadi ◽  
Kevin J. Smith
Keyword(s):  
Catalyst Deactivation ◽  
Catalyst Activity ◽  
Ch4 Oxidation ◽  
Lean Burn ◽  
Oxidation Activity ◽  
Beneficial Effects ◽  
Temperature Programmed ◽  
The Impact ◽  
Monolith Catalysts ◽  
Thermal Stability Of

This study reports on the activity and stability of PdO/γ-AlOOH/γ-Al2O3 monolith catalysts, promoted with varying amounts of CeO2, for CH4 oxidation. Although the beneficial effects of CeO2 have been reported for powdered catalysts, this study used a cordierite (2MgO.2Al2O3.5SiO2) mini-monolith (400 cells per square inch, 1 cm diameter × 2.5 cm length; ~52 cells), washcoated with a suspension of γ-Al2O3 combined with boehmite (γ-AlOOH), followed by sequential deposition of Ce and Pd (0.5 wt.%) by wetness impregnation. The monolith catalysts’ CH4 oxidation activity and stability were assessed in the presence of CO, CO2, H2O and SO2 at low temperature (≤550 °C), relevant to emission control from lean-burn natural gas vehicles (NGVs). The CeO2 loading (0 to 4 wt.%) did not significantly impact the adhesion and thermal stability of the washcoat, but CeO2 reduced the inhibition of CH4 oxidation by H2O and SO2. The catalyst activity, measured by temperature-programmed methane oxidation (TPO) in a dry feed gas with 0.07 vol.% CH4, showed that adding CeO2 to the γ-AlOOH/γ-Al2O3 washcoat suppressed the activity of the catalysts; whereas, CeO2 improved the catalyst activity when H2O (2 and 5 vol.%) was present in the feed gas. Moreover, adding CeO2 decreased catalyst deactivation that occurred in the presence of 10 vol.% H2O and 5 ppmv SO2 at 500 °C, measured over a 25 h time-on-stream (TOS) period. The highest catalyst activity and stability for CH4 oxidation in the presence of H2O was obtained by adding 2 wt.% CeO2 to the washcoat.

Sign in / Sign up

Export Citation Format

Share Document