Novel approaches to the degradation of nitrophenols using TiO₂-biopolymer-ligand-metal complex as photocatalysts

Nitrophenols has become a significant threat to the ecosystem and the health of the human beings. Photocatalytic degradation is considered to be the utmost competent approach for the amputation of nitroaromatic pollutants. In this research, 2-nitrophenol (MNP), 2,4-dinitrophenols (DNP), and 2,4,6-trinitrophenol or picric acid (PA) are taken for the degradation studies using the photo-Fenton catalyst of synthesized TiO₂ nanoparticle modified with biopolymer containing organic and inorganic functionalities. The morphological study reveals the uniformly distributed TiO₂ nanoparticles (15 nm) surfaces are encapsulated by the active site-rich chitosan-ligand-copper complex facilitating more absorption and enhancing the photocatalytic activity toward the target molecules. The UV spectra confirm the predominant shifting of absorption peak in the range 305–310 nm which results due to the formation of TiO₂-CBGCu nanocomposites. The zeta potential of the synthesized nanocomposites TiO₂-CBGCu 5%, TiO₂-CBGCu 10%, and TiO₂-CBGCu 20% are − 12, − 20, and − 29 mV which reveals that the value increases with the increase in CBGCu content which in turn signifies the more stability in aqueous solution. Amid the prepared nanocomposites, TiO₂-CBGCu 10% demonstrates the imperative catalytic performances toward MNP, DNP, and PA pollutants along with the Fenton’s reagent at pH 3.0 under visible light and solar light. It shows effective degradation for strong acid PA within 18 min in visible light compared to MNP and DNP due to the presence of more active sites in the synthesized nanocomposites. This work has created awareness about the multifunctional catalyst and the effectiveness of the same has opened a new passage to eliminate nitrophenols from the agonized environment.