Absorption of chlorine into aqueous bicarbonate solutions and aqueous hydroxide solutions

The absorption of Cl-2 into aqueous bicarbonate and aqueous hydroxide solutions was studied both experimentally and theoretically. The rate coefficient of the reaction between Cl-2 and OH- was estimated over the temperature range of 293-312 K and fitted by the Arrhenius equation: k(24)=3.56X10(11)exp(-1,617/T). If Cl-2 were assumed to react only with water and OH- in an aqueous bicarbonate solution, the predicted absorption rate would be much lower than that experimentally measured. This suggests that Cl-2 reacts with HCO3- in an aqueous bicarbonate solution. The rate coefficient of the reaction between Cl-2 and HCO3- was estimated over the temperature range of 293-313 K and fitted by the Arrhenius equation: k(21)=5.63x10(10)exp(-4,925/T). More importantly, under absorption conditions, the amount of hydroxide consumed for absorbing a specific amount of Cl-2 into an aqueous hydroxide solution is almost twice the amount of bicarbonate consumed for absorbing the same amount of Cl-2 into an aqueous bicarbonate solution.