Reaction Kinetics of Fe2O3 and BaCO3 to Prepare Ba2Fe2O5

2014 ◽  
Vol 33 (4) ◽  
pp. 319-323 ◽  
Author(s):  
Jun-Hao Liu ◽  
Guo-Hua Zhang ◽  
Kuo-Chih Chou

AbstractCarbon dioxide is a greenhouse gas and substantially affects the global warming and climate change, so study on the adsorption of carbon dioxide is very urgent. As a new CO2 captor, Ba2Fe2O5 was prepared by the solid state reaction of Fe2O3 with BaCO3, following formula Fe2O3 + 2BaCO3 = Ba2Fe2O5 + 2CO2. The reaction kinetics in isothermal condition was investigated by using the method of thermo-gravimetric analyzer (TGA). It was found that the reaction of Fe2O3 with BaCO3 was controlled by the diffusion step in the product layer, and the kinetics process could be described by the RPP model (Real Physical Picture) with the apparent activation energy extracted to be 161.122 kJ/mol.

Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.


2016 ◽  
Vol 33 ◽  
pp. 186-195 ◽  
Author(s):  
Abdelbaki Benamor ◽  
Mohammed Jaber Al-Marri ◽  
Majeda Khraisheh ◽  
Mustafa S. Nasser ◽  
Paitoon Tontiwachwuthikul

2020 ◽  
Vol 10 (6) ◽  
pp. 2014 ◽  
Author(s):  
Mariano Pierantozzi ◽  
Sebastiano Tomassetti ◽  
Giovanni Di Nicola

The most commonly used refrigerants are potent greenhouse gasses that can contribute to climate change. Hydro-Fluoro-Olefins are low Global Warming Potential fluids. A summary of our experimental research activity on the thermodynamic properties of two environmentally friendly Hydro-Fluoro-Olefins, namely R1234yf and R1234ze(E), is reported. In particular, the measurements were performed with an isochoric apparatus and the apparatus specifically built to reach temperatures down to about 100 K. The data elaboration confirms the validity of the choice and that R1234yf and R1234ze(E) can be adopted in many domestic applications. Moreover, considering the reduction of the flammability issues of R1234yf and R1234ze(E), the properties of binary systems containing these fluids and carbon dioxide were analyzed. The presented mixtures could be very interesting for low-temperature applications such as cascade cycles.


2013 ◽  
Vol 39 (3) ◽  
pp. 115-126 ◽  
Author(s):  
Yucheng Cao ◽  
Ewelina Staszewska

Abstract Uncontrolled emissions of landfill gas may contribute significantly to climate change, since its composition represents a high fraction of methane, a greenhouse gas with 100- year global warming potential 25 times that of carbon dioxide. Landfill cover could create favourable conditions for methanotrophy (microbial methane oxidation), an activity of using bacteria to oxidize methane to carbon dioxide. This paper presents a brief review of methanotrophic activities in landfill cover. Emphasis is given to the effects of cover materials, environmental conditions and landfill vegetation on the methane oxidation potential, and to their underlying effect mechanisms. Methanotrophs communities and methane oxidation kinetics are also discussed. Results from the overview suggest that well-engineered landfill cover can substantially increase its potential for reducing emissions of methane produced in landfill to the atmosphere.


Author(s):  
Malik Šehović ◽  
Lars Robben ◽  
Thorsten M. Gesing

AbstractWe report on the phase transformation and the reaction kinetics of aluminosilicate nitrite-sodalite |Na


2008 ◽  
Vol 21 (23) ◽  
pp. 6141-6155 ◽  
Author(s):  
Graeme L. Stephens ◽  
Todd D. Ellis

Abstract This paper examines the controls on global precipitation that are evident in the transient experiments conducted using coupled climate models collected for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The change in precipitation, water vapor, clouds, and radiative heating of the atmosphere evident in the 1% increase in carbon dioxide until doubled (1pctto2x) scenario is examined. As noted in other studies, the ensemble-mean changes in water vapor as carbon dioxide is doubled occur at a rate similar to that predicted by the Clausius–Clapeyron relationship. The ratio of global changes in precipitation to global changes in water vapor offers some insight on how readily increased water vapor is converted into precipitation in modeled climate change. This ratio ɛ is introduced in this paper as a gross indicator of the global precipitation efficiency under global warming. The main findings of this paper are threefold. First, increases in the global precipitation track increase atmospheric radiative energy loss and the ratio of precipitation sensitivity to water vapor sensitivity is primarily determined by changes to this atmospheric column energy loss. A reference limit to this ratio is introduced as the rate at which the emission of radiation from the clear-sky atmosphere increases as water vapor increases. It is shown that the derived efficiency based on the simple ratio of precipitation to water vapor sensitivities of models in fact closely matches the sensitivity derived from simple energy balance arguments involving changes to water vapor emission alone. Second, although the rate of increase of clear-sky emission is the dominant factor in the change to the energy balance of the atmosphere, there are two important and offsetting processes that contribute to ɛ in the model simulations studied: One involves a negative feedback through cloud radiative heating that acts to reduce the efficiency; the other is the global reduction in sensible heating that counteracts the effects of the cloud feedback and increases the efficiency. These counteracting feedbacks only apply on the global scale. Third, the negative cloud radiative heating feedback occurs through reductions of cloud amount in the middle troposphere, defined as the layer between 680 and 440 hPa, and by slight global cloud decreases in the lower troposphere. These changes act in a manner to expose the warmer atmosphere below to high clouds, thus resulting in a net warming of the atmospheric column by clouds and a negative feedback on the precipitation.


Sign in / Sign up

Export Citation Format

Share Document