La 3+ -Schiff base Complex for the Degradation of Rhodamine B: Kinetic Studies and Reactive Species Identification

Abstract

The research investigates the nature of the La-H₂L complex using molar conductivity experiments and UV-visible spectroscopy, subsequently exploring its photocatalytic activity for the degradation of Rhodamine B (RhB) dye. Photocatalytic degradation of RhB was evaluated under UV light, with optimization studies conducted for pH, initial dye concentration, and catalyst dosage. The decay proceeded according to pseudo-first-order kinetics, exhibiting a rate constant of 0.0169 min^− 1. Scavenger studies identified hydroxyl radicals as the main reactive species along with holes and superoxide radicals. HRMS spectra revealed intermediate products formed during degradation, elucidating plausible degradation pathways. The La-H₂L complex demonstrated high stability and reusability, maintaining significant degradation efficiency over four cycles. XRD and FTIR spectra confirmed the stability of the complex after degradation. These findings highlight the potential of the La-H₂L complex as an efficient and stable photocatalyst for environmental remediation applications.