Bisphenol A/Bisphenol F mineralization in the presence of self-decorated carbon-QDs@Bi2O2CO3/Ti3C2/g-C3N4 nanocomposites under multi-frequency ultrasound assisted sonophotocatalysis

Abstract

Herein, we attempted to synthesize a novel, highly efficient, surface-modified nanocatalyst supported by emerging 2D materials such as MXene (Ti₃C₂). A Bi₂O₂CO₃/Ti₃C₂/g-C₃N₄ ternary Z-scheme nanostructure tethered with self-decorated Carbon Quantum Dots (C-QDs) was successfully synthesized via a simple hydrothermal method. The study presents a pioneering attempt of multi-frequency ultrasound assisted sonophotocatalysis (MFASP) for the catalytic degradation of bisphenols. The surface morphology and various contours of pristine and nanocomposites were confirmed through various analytical techniques. The decorated C-QDs, ranging from 6 to 8 nm in size were uniformly distributed across the surface of the resulting nanocomposites. The sonophotocatalytic efficiency for BPA degradation was evaluated under various operational conditions, including catalytic dosage, combinational frequencies, and nanocatalyst variations. Notably, under 20 + 40 + 80 kHz sonophotocatalytic conditions, the C-QDs@Bi₂O₂CO₃/Ti₃C₂/g-C₃N₄ catalyst achieved 80 % degradation of BPA within 90 min (k = 0.0180 min⁻¹). The comparison studies revealed that the order BPA elimination at MFASP was BTG > BGC > BOC > TiO₂ > BMC > g-C₃N₄ > Ti₂C₃. The enhanced production of hydroxyl radicals in multi-frequency conditions was confirmed via terephthalic acid dosimetry method. Additionally, an attempt was conducted under optimized MFASP conditions for the simultaneous removal of BPA and BPF. Ultimately, more than 16 degradation intermediates proceeded through 4 different pathways (ring rupture, decarboxylation, dehydroxylation, bis-benzene ring cleavage) were identified by HRMS/QToFMS analysis, and a plausible decontamination mechanism was proposed.