Reduction of CO2 emission through a photocatalytic process using powder and coated zeolite-supported TiO2 under concentrated sunlight irradiation

The efficiency of a novel synthetic zeolite (Ze) prepared from stone cutting sludge and a natural zeolite (clinoptilolite, Cp) as the support of TiO 2 photocatalyst was examined for the CO 2 removal under solar irradiation using a designed parabolic trough collector (PTC). The used samples were characterized using XRF, BET, SEM/EDS, and XPS analyses. The enhanced sunlight irradiation obtained by PTC increased the performance of CO 2 photocatalytic removal. The maximum CO 2 adsorption by TiO 2 –Ze and TiO 2 –Cp composites was 21.1% and 28.4% which increased to 61.8% and 78.9% under sunlight irradiation, respectively. The efficiency of zeolite–TiO 2 composites for CO 2 removal was approximately two times higher than zeolites and TiO 2 alone. The performance of TiO 2 –Ze-coated composite with lower use of photocatalyst for CO 2 adsorption and photocatalytic removal was better than that of powder one. Regeneration of TiO 2 –Ze using NaOH solution improved its removal efficiency. The adsorption behavior of CO 2 on TiO 2 –Ze composite was well described by the Langmuir isotherm and the pseudo-first-order kinetic model. This work promises CO 2 reduction using natural and synthetic zeolite as an efficient photocatalyst support under solar irradiation.