چكيده به لاتين
Protecting water as the basis of human and environmental survival is very fundamental. Organic pigments are known as one of the types of pollution of water resources, and various methods have been used to remove these pollutions. In this research, copper sulfides as well as its composites with graphite carbon nitride in different ratios were synthesized by solution combustion method and used as photocatalysts to remove methylene blue pollutant. Since by controlling the parameters in the solution combustion synthesis, a higher specific surface area and probably a higher photocatalytic performance can be achieved, in order to innovate in this research, the synthesis of copper sulfide was carried out by the solution combustion method. In this study, Se Abe copper nitrate was used as a copper source and thiourea, thioacetamide and glycine were used as sulfur and fuel sources in solution combustion synthesis. The effect of different thiourea, thioacetamide and glycine fuels and their mixture on copper sulfides and CuS/g-C3N4 composites by X-ray diffraction pattern (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), Diffuse Reflectance Spectroscopy (DRS), Ultraviolet-Visible Absorption Spectroscopy (UV-Vis) and Photoluminescence Spectroscopy (PL) were investigated. The photocatalytic performance of all samples was investigated in detail, and the optimal photocatalytic performance can be attributed to the synthesis of smaller sized particles. According to the results, the sample of copper sulfide synthesized with the ratio of glycine to thioacetamide 2 showed the highest photocatalytic degradation (86.8%) during 3 hours of visible light irradiation, the reason for the superiority of this performance was the formation of smaller spherical particles than other samples. Due to the good performance of the 2TA4Gl copper sulfide sample, its composite samples were synthesized in 90%, 80%, and 70% weight percentages of copper sulfide with graphite carbon nitride. According to the results, it can be seen that CuS in the composite composition with g-C3N4, in a low amount of copper sulfide (70%) provides better photocatalytic activity than the rest of the composites, which according to previous reports, the higher percentage of copper sulfide in the composite, leads to Blocking of active surface sites in the composite reduces light absorption and consequently photocatalytic performance. Also, the increased band gap of the 70% CuS composite sample (3.18 eV) also showed that the electron-hole recombination has decreased to a great extent, so its photocatalytic activity has increased. It is worth mentioning that in previous reports, superior photocatalytic activity was obtained when the majority of this binary composite was formed by graphitic carbon nitride and copper sulfide was only a small part of the composite. However, for more certainty, copper sulfide and graphite carbon nitride composites with different weight percentages need to be investigated. Finally, according to the results, it can be said that copper sulfide is a good absorber for pollutants and not a good destroyer.
