The effects of Ag nanoparticles deposition on the photocatalytic activity of C3N4 for the degradation of tetracycline

Some organic contaminants can enter drinking water without being removed by conventional treatment methods. One group of these contaminants are antibiotics that, if present in water and entering the human body, can cause bacterial resistance over time. Therefore, finding new methods and materials that can remove this group of pollutants from the environment is significant. In the present study, carbon nitride nanolayers were prepared by heat decomposition of dicyanamide and then silver nanoparticles were deposited on the surface of carbon nitride. The photocatalytic properties of the synthesized composites for the degradation of the tetracycline in water were then investigated. The obtained powder was characterized by transmission electron microscopy, X-ray diffraction, surface area test and ultraviolet-visible spectroscopy. The results showed that carbon nitride was successfully synthesized and silver nanoparticles with average size of 30 nm were deposited on the carbon nitride surface. The produced samples showed absorption in the range of visible light (400 to 700 nm). Addition of silver nanoparticles improved the photocatalytic properties of carbon nitride by preventing electron-hole recombination. The sample containing 2 weight percent of silver had the highest photocatalytic properties. The produced composite samples degraded the tetracycline antibiotic in the water up to 89% after 30 min. The reaction rate constant increased from 0.0087 min-1 in the pure carbon nitride sample to 0.036 min-1 after deposition of silver nanoparticles.