关键词: 二氧化碳, 吸收, 反应动力学, 模型

Abstract: pH measurement was adopted to obtain the absorption rate of CO₂. Liquid composition was correlated to the dynamic change of pH. Piecewise fitting was further used on liquid composition to obtain the CO₂ absorption rate. Therefore, the liquid composition on the absorption rate of CO₂ was then achieved. For low concentration sodium hydroxide, the absorption rate of CO₂ does not change until CO₂ physical absorbed into NaHCO₃. While for high concentration NaOH, CO₂ absorption rate decreases when NaOH is fully converted to Na₂CO₃. However, within the two stages of absorption, CO₂ absorption rate does not change. When CO₂ is absorbed into NaHCO₃, CO₂ absorption rate decreases with the increase of saturation state for the solution. As for CO₂ absorption into NaOH, both CO₂ and sodium concentration promote the absorption, with more influence by sodium concentration; For CO₂ absorption into Na₂CO₃, the absorption rate does not increase when the concentration of Na₂CO₃ is higher 0.05mol/L; For CO₂ absorption into NaHCO₃, low concentration NaHCO₃ promotes the absorption of CO₂ while high concentration of NaHCO₃ inhibits CO₂ absorption due to salt-out effect. To reduce CO₂ absorption into solutions, high concentration of NaHCO₃ larger than 0.5mol/L is preferable.

Key words: carbon dioxide, absorption, chemical kinetics, model