Novel sandwich like interfacial engineering of Cu NPs on CuAl2O4 anchored Bi4O5Br2 nanoflower Z-scheme nano-heterojunction for enhanced photocatalytic degradation of doxycycline and tetracycline

Abstract

Background

The contamination of aquatic systems with antibiotics poses a significant threat to both human health and aquatic ecosystems, disrupting microbial communities, harming aquatic organisms, and contributing to the proliferation of antibiotic-resistant bacteria that compromise public health and medical treatment efficiency. In this study, the antibiotics doxycycline (DOX) and tetracycline (TET), widely used pharmaceuticals, are highlighted as complex contaminants that not only persist in the environment but also act as pollutants causing adverse effects.

Methods

This study employed interfacial engineering of Cu nanoparticles on CuAl₂O₄ to construct a Z-scheme heterojunction with varying concentrations of Bi₄O₅Br₂ (10, 20 and 30%) using an ultrasonication-assisted co-precipitation method. The resulting CuAl₂O₄- Bi₄O₅Br₂ nanocomposites (CCB NCs) demonstrated exceptional stability and photocatalytic efficiency under visible light irradiation, leveraging enhanced charge separation and transfer mechanisms to achieve superior degradation of DOX and TET.

Findings

The CCB NCs demonstrated remarkable photocatalytic degradation efficiencies of 95.2, 95.7 and 95.4 for TET, DOX and their combination which showcased the enhanced stability and reusability. The sandwich-like interfacial engineering of Cu nanoparticles on CuAl₂O₄ anchored with Bi₄O₅Br₂ nanoflowers facilitated Z-scheme nano-heterojunction formation, contributing to a larger surface area, narrow bandgap energy, high visible light absorption, and reduced recombination rates. PL and EIS analyses validated the superior charge separation and transfer abilities of the NCs. Structural, morphological, and compositional analyses using XRD, SEM, TEM, and XPS confirmed the material's characteristics. The photocatalytic mechanism was elucidated through ESR and radical scavenging experiments. The degradation pathway of TET and DOX was proposed via GC–MS/MS, and ECOSAR analysis confirming the nontoxicity of intermediates and end products to algae, fish, and daphnia. These findings underscore the potential of CCB NCs for real-time wastewater treatment applications and manufacturing innovation in future.