The efficiency of the visible /H2O2/UV/LaMnO₃ nano photocatalytic compound in removing reactive black 5 (RB5) dye from aqueous solutions

Heliyon. 2025 Feb 1;11(4):e42307. doi: 10.1016/j.heliyon.2025.e42307. eCollection 2025 Feb 28.

Abstract

Perovskites are promising catalysts for destructing azo pollutants. Lanthanum manganate performs well under visible light irradiation, making it an ideal material to maximize using solar energy for catalysis. To investigate the capability of nanoperovskite LaMnO₃ in removing reactive black 5 (RB5) LaMnO₃ nanoparticles were prepared by the sol-gel method and used as photocatalysts for the degradation experiments of RB5 dye from aqueous. The structural characteristics, size, morphology, and optical properties of the synthesized nanoperovskite were confirmed through analyses and spectroscopic methods (FT-IR, XRD, FESEM, BET, DLS, and DRS). Highly porous LaMnO₃ nanoperovskite with a good band gap makes it catalytic and photocatalytic. The dye concentration (5 mg/l), oxidant concentration (50 mg/l), LaMnO₃ photocatalyst volume (100 mg), temperature (25 °C), retention time (40 min), pH = 5, and UVA lamp source (9 W) were optimized for RB5 degradation. A dye degradation efficiency of 70 % was obtained in these conditions. By changing the type of lamp to UVC the efficiency was 45 % and without a light source efficiency was below 10 %. An increase of 0.07 % in the BOD/COD degradability index shows the high LaMnO₃ photocatalyst's efficiency. Therefore, the visible nanophotocatalytic compound/H2O2/UV/LaMnO₃ could remove RB5 dye, yielding a high dye degradation percentage in optimal conditions.

Keywords: Heterogeneous catalyst; Oxidative degradation; Perovskite; Photocatalyst; Reactive black 5 dye; Ultraviolet–visible light; Wastewater.