A Novel Carbon Dioxide Desorption Phenomena using Potassium Acetate Aqueous Solution

A novel CO2 absorbent, 50–75 wt.% aqueous potassium acetate solution (AcK(aq)), which showed a CO2 absorption capacity of ~ 0.2 mol CO2/mol, and could almost immediately completely desorb CO2 on addition of 40 wt.% H2O at 30 ℃ was investigated. This novel phenomenon seemed contrary to the Le Chatelier's principle because H2O is reactant in this system. After characteristics of products by FTIR and XRD diffraction pattern, the novel desorption behavior was attributed to the acid-base reaction between KH(CH3COO)2 and KHCO3 precipitates within the absorbent sludge. As H2O was added, both compounds re-dissolved and CO2 was released. A similar observation was made when the absorbent sludge was heated to temperatures above 60 ℃, owing to an increase in solubility with temperature. The mechanism of CO2 captured and released by AcK(aq) was proposed in this study. This novel energy-saving CO2 absorption and desorption behavior reveals that AcK(aq) has a high potential for application in the commercial production process.