Novel Bi2O3/MWCNT@TiO2 nanocomposite for enhanced photocatalytic degradation of Brilliant blue dye under visible light and ozonation

This study aimed to develop an efficient photocatalyst for the degradation of Brilliant Blue G (BBG) dye in aqueous solutions under visible light and ozonation. The research focused on synthesising and characterising a novel Bi 2 O 3 /MWCNT@TiO 2 nanocomposite (BMT) to enhance photocatalytic performance through synergistic effects. The Bi 2 O 3 /MWCNT@TiO 2 nanocomposite was prepared using a wet impregnation method. Techniques such as PXRD, UV-visible DRS, BET surface area analysis, SEM-EDX, and TEM were employed to evaluate structural and morphological properties. Variants, BMT-1 to BMT-5 , were synthesised with varying compositions and extensively characterised. The results revealed that BMT-1 and BMT-5 exhibited particle sizes in the range of 20-45 nm and band gaps of 2.76 eV and 3.0 eV, respectively, indicating their suitability for visible-light-driven photocatalysis. The nanocomposites demonstrated exceptional efficiency in degrading BBG dye under solar irradiation and ozonation. At an optimal catalyst dose of 0.025 g/L and an initial dye concentration of 20 ppm, a maximum degradation efficiency of 98.3% was achieved. The influence of pH was investigated at acidic (pH 3), natural, and alkaline (pH 11) conditions. BMT-5 exhibited superior performance at the dye's natural pH, while BMT-1 showed high degradation of 97% and 93% at pH 3 and 11, respectively. Additionally, the catalysts displayed excellent reusability, confirming their stability and potential application for practical wastewater treatment applications. This work highlights the usefulness of Bi 2 O 3 /MWCNT@TiO 2 as a robust photocatalyst for pollutant degradation under environmentally relevant conditions.