چكيده به لاتين
In this project, first, titanium dioxide nanoparticles were synthesised using different weight percentages of phosphoric acid in order to reach different crystallite sizes by the co-precipitation method. The goal was to reach the optimal crystal size of titania for the degradation of Rhodamine B solution. However, in order to improve the photocatalytic activity and move the edge of the absorption spectrum towards higher wavelengths and a lower energy gap and to check the efficiency in the presence of visible light, they were coupled with graphite carbon nitride by the wet impregnation method. Characterization of catalysts using infrared spectroscopic analysis (FTIR), nitrogen absorption and desorption analysis (BET and BJH), X-ray diffraction (XRD), scanning electron microscope (FESEM), X-ray energy dispersive spectroscopy (EDS), ultraviolet-visible reflection spectroscopy)(DRS), and photoluminescence emission spectroscopy (PL) were performed. The results showed that all titania samples have the same isotherm and mesopore structure. According to the analysis, increasing the content of phosphoric acid as a peptizing agent changed the crystal size and pore size distribution to a smaller size and increased the specific surface area and pore volume. With increasing the amount of acid, surface reduction, an increase in particle size, and lumpiness were observed. The optimal sample showed a better pore distribution, and a spherical structure like titania particles and a layered block like graphitic carbon nitride were determined. EDS analysis verified that the carbon materials were successfully coupled with the optimal photocatalyst. As the calcination temperature increased from 300 to 700 °C, the intensity of the peak increased, which showed the increase in crystallinity of TiO2, and at 700 °C, the rutile phase was formed, but this increase resulted in sintering and a reduction of the specific surface area. The degradation process of rhodamine B up to 600 °C was observed to increase and then decrease. By examining the effect of operating conditions on the final composite, it was shown that under optimal operating conditions, 98.6% of the colour is removed after 20 minutes of visible light irradiation. The results of the stability tests showed that 84.28% of the paint was degraded after 5 cycles. Also, the destruction for the anionic dye indigo carmine (IC) and two antibiotics, ciprofloxacin (CIP) and ofloxacin (OFL), shows the destruction of 94% of the IC pollutant within 20 minutes of irradiation and 99.1% and 98% destruction for the pharmaceutical pollutants CIP and OFL, which expresses the unique photocatalytic power of this composite.
