Kinetics and liquid-gas mass transfer during the photocatalytic CO2 reduction: effect of the photocatalyst load and stirrer speed

BALLARI, MARÍA DE LOS MILAGROS; EDELMANNOVÁ, MIROSLAVA; RICKA, RUDOLF; RELI, MARTIN; KOCÍ, KAMILA

Cusco

Conferencia; 5th Iberoamerican Conference on Advanced Oxidation Technologies; 2022

A kinetic study of the photocatalytic CO2 reduction in a TiO2 slurry considering the mass transfer from liquid to gas phase of the main reaction by-products, CH4 and H2, was performed. Simplified kinetic expressions were proposed based on the photocatalytic complex reaction mechanism of the CO2 reduction and including the dependence with the radiation field in the TiO2 suspension. The main studied operating conditions were the magnetic stirrer speed and the TiO2 photocatalyst mass concentration. A good agreement between the experimental data and mathematical model predictions was observed. The fastest stirring speed in the liquid phase guarantees quicker species transport to the gas phase. On the other hand, the best products yield was observed for the lowest tested photocatalyst concentration, which presents better irradiation distribution in the reaction media and less particles agglomeration providing higher available active surface for the reaction.