Preparation of g-C3N4-PEI Quantum Dot Photocatalytic Flower and Its Performance Study for Degrading Tetracycline

This paper uses carbon nitride and PEI as precursors to prepare g-C3N4-PEI water-soluble photocatalytic materials and then uses that material and sodium alginate hydrogel to construct photocatalytic flowers. The main research content and conclusions are as follows:
(1) Five samples of g-C3N4-PEI were prepared using different ratios of both g-C3N4 and PEI materials; the g-C3N4: PEI=1:5 sample has the best degradation performance with a TC removal rate of 73.546%. The UV-Vis, FTIR, fluorescence, and XPS characterizations showed that g-C3N4-PEI had the basic s-triazine ring, carbon, and
nitrogen atom heterocycle (2p orbitals), graphitic C–N network, amino and hydroxyl groups. The optimal light absorption wavelength is 368(nm), and the quantum yield (λex = 340 nm) was 20.9%, using quinine sulfate as a standard.
(2) Throughout the experiments, the flower's removal rate of TC was (absorption 50%, photodegradation 66.75%), higher than pure g-C3N4 (6.23% and 52.76%).