Absorption of chlorine into aqueous bicarbonate solutions and aqueous hydroxide solutions

Removal of chlorine from certain gas streams may be of industrial importance for certain chemical processes. The absorption of Cl{sub 2} into aqueous bicarbonate and aqueous hydroxide solutions was studied both experimentally and theoretically. The rate coefficient of the reaction between Cl{sub 2} and OH{sup {minus}} was estimated over the temperature range of 293--312 K and fitted by the Arrhenius equation: k{sub 24} = 3.56 {times} 10{sup 11} exp({minus}1,617/T). If Cl{sub 2} were assumed to react only with water and OH{sup {minus}} in an aqueous bicarbonate solution, the predicted absorption rate would be much lower than that experimentally measured. This suggests that Cl{sub 2} reacts with HCO{sub 3}{sup {minus}} in an aqueous bicarbonate solution. The rate coefficient of the reaction between Cl{sub 2} and HCO{sub 3}{sup {minus}} was estimated over the temperature range of 293--313 K and fitted by the Arrhenius equation: k{sub 21} = 5.63 {times} 10{sup 10} exp({minus}4,925/T). More importantly, under absorption conditions, the amount of hydroxide consumed for absorbing a specific amount of Cl{sub 2} into an aqueous hydroxide solution is almost twice the amount of bicarbonate consumed for absorbing the same amount of Cl{sub 2} into an aqueous bicarbonate solution.