Statistical optimization of active chlorine production from a synthetic saline effluent by electrolysis

This study examines the possibility to optimally produce active chlorine from a synthetic concentrate of seawater by electrolysis using an experimental design methodology. Different operating parameters were investigated such as current density, reaction time, hydrochloric acid concentration and chloride ion concentration. Using a 24 factorial matrix, the best performance for active chlorine production (46 mg/l of HClO) was obtained at a current intensity of 1.6 A during 35 min of treatment time in the presence of 0.11 M of H3O+ and 0.8 M of NaCl. The current intensity and treatment time were the main parameters influencing the active chlorine production. Subsequently, a central composite design methodology has been investigated to determine the optimal experimental parameters for chlorine production. The electrolytic cell applied under optimal conditions (at a current intensity of 1.6 A during 27 min in the presence of 0.11 M of NaCl and 0.8 M of H3O+) is able to produce 31 mg/l of chlorine for an energy consumption of 0.54 kWh/m3.

► RSM is a helpful method to study chlorine production by saline water electrolysis.
► Time and current intensity were the main parameters influencing chlorine production.
► The effect of these two main factors is around 82.8% on the investigated response.
► Active chlorine (31 mg/l) could be optimally produced for 0.54 kWh/m3