PHOTOCATALYTIC REACTIVATION OF g-C3N4 BASED NANOSORBENT

In this work, we present new preparation method, photocatalytic activity and photocatalytic reactivation of photoactive layered graphitic carbon nitride (g-C3N4), which was incorporated into silica structure containing zinc-silicate nanoparticles (ZnO-m center dot SiO2). Prepared material exhibits more than ten times larger specific surface area than pure bulk g-C3N4. Material was prepared by sonication of intensively stirred aqueous solution of zinc acetate and g-C3N4 while sodium water glass was slowly added by drops into the mixture. Sodium water glass reacted with zinc acetate, which was in excess, and composite ZnO-m center dot SiO2 nanoparticles has precipitated on g-C3N4 nanosheets. Prepared nanodispersion was turned into powder material by vacuum freeze drying technique. This technique preserves most of particles specific surface area by conserving chaotic arrangement of given particles in water solution. Prepared powder was further calcinated at 500 degrees C for one hour. Photocatalytic reactivation was tested on TiO2 and ZnO-m center dot SiO2/g-C3N4 nanocomposite. Material was stirred in the dark with aqueous solution of methylene blue for one hour to reach an adsorption-desorption equilibrium. Material with adsorbed dye on its surface was than separated and collected from solution by centrifugation, transferred into pure demineralised water and adsorbed dye was than decomposed under LED light irradiation within half an hour. Dispersion was centrifugated again to separate by-products, dried by vacuum freeze drying and subjected to sorption process again. Although kinetic characteristics for both materials were different, sorption properties of both materials did not change after reactivation.