Comparison among OH, N and P functionalized carbon quantum dots/TiO2 nanocomposites for food industry wastewater remediation

TiO2 nanoparticles present limited efficiency under visible light in photocatalytic for food and agriculture wastewater remediation. Hence, the exploration of modifications to enhance their photocatalytic activity has been studied. Carbon Quantum Dots (CQDs) have recently gained attention as functional coatings for TiO2, but a comparison between different types of CQDs has not been performed before. In this study, TiO2 nanoparticles coated with CQD treated with NaOH, HNO3, and H3PO4 were synthesized and named OHTiO2, NTiO2 and PTiO2. The materials were characterized for the photocatalytic degradation of glucose, representing jam industry wastewater and showed enhanced photocatalytic activity under visible light irradiation when compared to bare TiO2 nanoparticles. The type of functional groups on the CQDs played a crucial role in determining the photocatalytic performance of the composites. In one case, they reduce the band gap, as observed in the NTiO2, while in another case, they mitigate the influence of interferents, as observed in the PTiO2. This research provides valuable insights into the design and optimization of functionalized quantum dots for photocatalytic applications.