THE EVOLUTION OF CARBON DIOXIDE IN THE A.-C. ELECTROLYSIS OF SODIUM CARBONATE AND BICARBONATE SOLUTIONS, AND THE DISCHARGE POTENTIALS OF CARBONATE AND BICARBONATE IONS

1934 ◽  
Vol 11 (4) ◽  
pp. 539-546
Author(s):  
J. W. Shipley

The a.-c. electrolysis of sodium carbonate solutions at voltages as high as 110, even when arcing occurs on the electrodes, does not cause the evolution of carbon dioxide. In the a.-c. electrolysis of aqueous bicarbonate solutions with platinum electrodes, hydrogen, oxygen and carbon dioxide are evolved freely until all the bicarbonate has been transformed to carbonate, after which the evolution of carbon dioxide ceases and only hydrogen and oxygen are given off. In a.-c. electrolysis of sodium bicarbonate solutions and solutions of the sodium salts of aliphatic acids, a deposit of finely divided platinum is formed on the electrodes. This deposit inhibits the evolution of carbon dioxide, hydrogen and oxygen, but does not affect the current flow. The decomposition potential of bicarbonate solutions in respect to the evolution of carbon dioxide on smooth platinum and with d.c. was found to be 2.2 volts, and of carbonate solutions, 3.5 volts. The anodic discharge potential of HCO3− is − 1.45 to − 1.50 volts, and of CO3−−, − 1.90 to − 1.95 volts. The evolution of carbon dioxide does not appear to cause any polarizing effect on the anode.

2021 ◽  
Vol 4 (10(112)) ◽  
pp. 38-44
Author(s):  
Mykola Porokhnia ◽  
Musii Tseitlin ◽  
Svitlana Bukhkalo ◽  
Vladimir Panasenko ◽  
Tetiana Novozhylova

This paper reports a study into the influence of temperature and gas consumption on the carbonization kinetics (saturation with carbon dioxide) of sodium carbonate-bicarbonate solution. The study also examined the quality and speed of crystal formation in this process. This research is predetermined by the environmental problems faced by modern enterprises that produce purified sodium bicarbonate – an insufficient degree of carbonization and, as a result, excessive air pollution with carbon dioxide, which did not participate in the reaction during the process. This study addresses these particular issues. As a result of using specialized laboratory equipment, it was found that an increase in the absorbent temperature from 79 to 85 °C leads to a decrease in the maximum degree of carbonization of the solution from 64 to 59 %. In contrast, the quality of the resulting sodium bicarbonate crystals improves but only in the range from 79 to 82 °C. With a further increase in temperature, the quality stabilizes. It is shown that the carbonization rate increases with increasing specific consumption of the absorbent (carbon dioxide) and is characterized by a negative correlation with the value of oversaturation of the absorbent in terms of NaНCO3. The quality of sodium bicarbonate crystals decreases with increasing gas velocity. Thus, it was reasonable to assume that the established dependence of the kinetics of carbonization of Na2CO3 and NaНCO3 solution on the gas velocity in the apparatus is explained by the inhibition of СО2 absorption, which is caused by the diffusion resistance of sodium bicarbonate crystallization. To improve the quality of crystals and the productivity of carbonization by reducing the supersaturation in terms of NaНCO3, it is recommended to introduce a seed crystal in the zone of binding of crystals in the carbonization columns.


1933 ◽  
Vol 25 (5) ◽  
pp. 528-531 ◽  
Author(s):  
C. R. Harte ◽  
E. M. Baker ◽  
H. H. Purcell

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 371-376 ◽  
Author(s):  
Lluís Palou ◽  
Joseph L. Smilanick ◽  
Josep Usall ◽  
Inmaculada Viñas

Control of citrus blue mold, caused by Penicillium italicum, was evaluated on artificially inoculated oranges immersed in water at up to 75°C for 150 s; in 2 to 4% sodium carbonate (wt/vol) at 20 or 45°C for 60 or 150 s; or in 1 to 4% sodium bicarbonate at room temperature for 150 s, followed by storage at 20°C for 7 days. Hot water controlled blue mold at 50 to 55°C, temperatures near those that injured fruit, and its effectiveness declined after 14 days of storage. Sodium carbonate and sodium bicarbonate were superior to hot water. Temperature of sodium carbonate solutions influenced effectiveness more than concentration or immersion period. Sodium carbonate applied for 150 s at 45°C at 3 or 4% reduced decay more than 90%. Sodium bicarbonate applied at room temperature at 2 to 4% reduced blue mold by more than 50%, while 1% was ineffective. In another set of experiments, treatments of sodium bicarbonate at room temperature, sodium carbonate at 45°C, and hot water at 45°C reduced blue mold incidence on artificially inoculated oranges to 6, 14, and 27%, respectively, after 3 weeks of storage at 3°C. These treatments reduced green mold incidence to 6, 1, and 12%, respectively, while incidence among controls of both molds was about 100%. When reexamined 5 weeks later, the effectiveness of all, particularly hot water, declined. In conclusion, efficacy of hot water, sodium carbonate, and sodium bicarbonate treatments against blue mold compared to that against green mold was similar after storage at 20°C but proved inferior during long-term cold storage.


1941 ◽  
Vol 33 (9) ◽  
pp. 1129-1131 ◽  
Author(s):  
J. Harold Smith ◽  
Elton L. Quinn

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