Continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution

• Published in: Journal of hazardous materials 2009-11, Vol.171 (1), p.606-612
• Main Authors: Kim, Kwang-Wook, Kim, Yeon-Hwa, Lee, Se-Yoon, Lee, Eil-Hee, Song, Kyusuk, Song, Kee-Chan
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; Carbon - chemistry; Carbon dioxide; Carbon Dioxide - chemistry; Carbonates; Carbonates - chemistry; Cations; Chemical engineering; Continuous; Decarbonation; Electrochemistry - methods; Electrolytic; Exact sciences and technology; Feeding; Gases; Hydrogen-Ion Concentration; Hydroxides - chemistry; Ion exchange; Metals - chemistry; Models, Chemical; Pollution; Recovery; Salt solutions; Salts - chemistry; Sodium Hydroxide - chemistry; Stacked-cell; Steady state; Water Pollutants, Chemical - analysis; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.06.043

This work studied the characteristic changes of a continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution with changes of operational variables in an electrolytic system which consisted of a cell-stacked electrolyzer equipped with a cation exchange membrane and a gas absorber. The system could completely recover the carbonate salt solution from a uranyl carbonato complex solution in a continuous operation. The cathodic feed rate could control the carbonate concentration of the recovered solution and it affected the most transient pH drop phenomenon of a well type within the gas absorber before a steady state was reached, which caused the possibility of a CO 2 gas slip from the gas absorber. The pH drop problem could be overcome by temporarily increasing the OH − concentration of the cathodic solution flowing down within the gas absorber only during the time required for a steady state to be obtained in the case without the addition of outside NaOH. An overshooting peak of the carbonate concentration in the recovered solution before a steady state was observed, which was ascribed to the decarbonation of the initial solution filled within the stacked cells by a redundant current leftover from the complete decarbonation of the feeding carbonate solution.