Structural characterization of carbon quantum dots derived from tea residue and their photocatalytic application in CQDs-modified Al2(SO4)3 nanoparticles for sustainable pesticide degradation

Effect of Carbon Quantum Dots (CQDs) on the photocatalyst performance of Al₂(SO₄)₃/CQDs composites. CQDs were synthesized from tea residue using a hydrothermal method, which has been studied. The investigation included a comprehensive nanostructure analysis through X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), UV–Vis Spectroscopy, and Photoluminescence (PL) Analysis. TEM revealed the formation of coral-shaped clusters in the Al₂(SO₄)₃/CQDs composite, with nanoparticle sizes ranging from 2 to 10 nm. Notably, the Al₂(SO₄)₃/CQDs II variant, comprising 95 % Al₂(SO₄)₃ and 5 % CQDs, demonstrated the highest photocatalytic performance. This composite effectively degraded fipronil pesticide, achieving an impressive 84 % degradation within 60 min. This performance can be attributed to several factors, including the narrowed d-spacing, the work effectiveness of hydroxyl radical active species, the lowest bandgap, and the profound impact on C–C bonds within Al₂(SO₄)₃/CQDs II. The findings suggest that the Al₂(SO₄)₃/CQDs composite holds great promise as an advanced material for photocatalytic pesticide degradation, thereby contributing to the broader goal of ensuring sustainable access to clean water resources. This study provides valuable insights into the design and development of advanced photocatalytic materials, with the potential to significantly impact the field of water purification and environmental sustainability.