Photocatalytic degradation of acetaminophen using a novel TiO2-orange peel-derived biochar composite: Synthesize, characterization and optimization of key factors

Abstract

The widespread presence of pharmaceutical pollutants like acetaminophen (ACT) poses a significant threat to aquatic ecosystems and human well-being. Herein, we employed a straightforward ultrasonic technique to synthesize TiO2 integrated with biochar derived from orange peel waste (TOBC) for the photocatalytic degradation of ACT. Parameters for the synthesis of TOBC, including biochar loading, ultrasonic power, and time, were optimized via Design Expert software and central composite design for response surface methodology (RSM-CCD). The resulting TiO2-orange peel-derived biochar 20 wt% (TOBC20) exhibited remarkable photocatalytic efficacy, achieving 94 % ACT degradation under optimized conditions (initial concentration = 20 mg. L−1, pH = 4, irradiation duration = 100 min, and catalyst dosage = 0.8 g. L−1). Thorough characterization, including XRD, FTIR, XPS, SEM, EDX, PL, EIS, and TPC analyses, offered insights into the biochar's innovative role as an electron acceptor and in separating electron-hole pairs. Trapping tests and ESR techniques elucidated the photocatalytic degradation mechanism, and the TOBC catalyst also demonstrated consistent stability over five cycles, confirming its suitability for eliminating non-biodegradable pharmaceuticals. Finally, results were validated by comparison with previous research, showing relatively consistent findings.