Journal of Applied Chemistry and Biotechnology 

About: Journal of Applied Chemistry and Biotechnology is an academic journal. The journal publishes majorly in the area(s): Catalysis & Aqueous solution. It has an ISSN identifier of 1935-0554. Over the lifetime, 670 publications have been published receiving 6796 citations.

The reversibility of the reaction CaCO3 ⇄ CaO+CO2

Abstract: The reversibility of the reaction CaCO3 ⇌ CaO+CO2 has been examined through a large number of cycles (up to 40), mainly at 866 °C. The decomposition to the oxide is always 100% but the reactivity of the oxide so formed to carbon dioxide falls off markedly after a rapid initial reaction. There is a large increase in surface area on going from the non-porous calcium carbonate to the oxide and this is due to the formation of pores, mostly very small (< 4 nm). The fast component of the back reaction is a surface reaction and the subsequent slow reaction is controlled by the slow diffusion of carbon dioxide through the newly formed carbonate layer. The reversibility of the reaction decreases with the number of cycles, rapidly at first and then more slowly: the first effect is probably due to loss of pore volume in the oxide and the second to sintering of the carbonate.

The glass‐ionomer cement, a new translucent dental filling material

Abstract: A new translucent cement, the product of the reaction between ion-leachable glass and an aqueous solution of polyacrylic acid, is described. Its properties, with particular reference to dental applications, are reported and a proposed setting mechanism is advanced.

Hydrolysis of aluminium alkoxides and bayerite conversion

Abstract: A study of hydrolysis of aluminium alkoxides as a function of water temperature, and structural transformation of the resultant hydroxides was conducted. Hot water hydrolysis of aluminium alkoxides produces boehmite, whereas cold water hydrolysis results in formation of amorphous monohydroxide. This amorphous phase contains OR groups whose removal by water during aging causes the material to convert to bayerite or boehmite. Bayerite conversion takes place below 80 °C by a dissolution-recrystallisation process in which the gradual liberation of OR groups by water appears to play an important role. Boehmite conversion takes place above 80 °C where vigorous liberation of OR groups occurs and the slow stoichiometric bayerite conversion diminishes. Neither conversion takes place in pure alcohol.

Equilibrium between carbon dioxide and aqueous monoethanolamine solutions

Abstract: The University of Alberta measured the partial pressure of carbon dioxide over aqueous monoethanolamine solutions (1.0, 2.5, 3.75, and 5.0 N) at temperatures of 25/sup 0/, 40/sup 0/, 60/sup 0/, 80/sup 0/, 100/sup 0/, and 120/sup 0/C. Partial pressures of CO/sub 2/ ranged between 0.2 and 6616 kPa. The results, which extend previously published data to higher partial pressures, were compared with two methods of prediction based upon a thermodynamic model.

The reactivity of calcium oxide towards carbon dioxide and its use for energy storage

Abstract: By using calcium carbonate powder of particle size ∼ 10 nm (and therefore of high surface area) it has been shown that the reaction CaCO3 ⇄ CaO + CO2 can be made almost wholly reversible. A reactivity of 93% was achieved, (i.e. 93% of the calcium oxide reacted with carbon dioxide) and this was maintained for 30 24-h decomposition-back reaction cycles at 629 °C with no detectable decrease. This material has an energy storage capacity of 200 Wh/lb, but only about 1 kWh/ft.3 When this calcium carbonate was pressed, however, to increase its bulk density (from 0.1 to ∼ 1 g/ml) there was a large decrease in its surface area and a smaller decrease in its reactivity on undergoing a few decomposition and back reaction cycles. Scaling up of the sample size from 20 mg to 10 g only had a small (× 3) effect on the rates of decomposition and back reaction.