Photocatalytic degradation of caffeine using graphitic carbon nitride as the catalyst

Research over the last few decades has shown that the pollutant contamination of the aquatic environment become a serious global problem. Due to the continuous and commonly ignorant release of pollutants without their prior treatment, we persistently influence the ecosystem and impact the living organisms. With this study, we present an attempt to degrade one of the pollutants, namely caffeine, with the non-toxic photocatalytic approach. Caffeine (CAF) was dispersed in a suspension of graphitic carbon nitride (CN) nanopowder, which was prepared by a simple thermal method at several treatment temperatures (at 500, 550, and 600 °C) using urea as a precursor. Synthesized CN catalysts were characterized using X-ray diffraction analysis (XRD) and photoluminescence (PL). Photocatalytic experiments were performed in an incubator under an ultraviolet A (UV-A) lamp (Supratec 18W/73, Osram) with a specified wavelength between 300 and 400 nm and a simulated solar lamp (Osram Ultra Vitalux 300W). We show that after the photo-degradation process, the concentration of CAF as a model pollutant was lower compared to the initial concentration (10 mgL-1 ). Furthermore, we also show how the thermal treatment of the CN influences the photocatalytic degradation of CAF. We also noticed that the degradation is faster under simulated solar irradiation compared to UV-A irradiation. For future work, we expect that the studied photocatalyst will be reusable through immobilization, which is also of utmost significance for their implementation under real conditions