Hedgehog-like ZnO nanostructures naturally formed in biochar: An innovative approach for cephalexin removal

Abstract

This study developed hedgehog-like ZnO nanostructures supported on biochar (B/ZnO), characterized by three-dimensional nanocrystal clusters radiating from a central core. These structures exhibit high specific surface area and porosity, enhancing their performance in adsorption and photocatalysis for removing emerging contaminants such as cephalexin (CEX) from aqueous solutions. The growing concern over antibiotics and their metabolites in water, coupled with the rise of antibiotic resistance, highlights the need for efficient methods to mitigate their environmental, agricultural, and health impacts. While optimization of ZnO particles for contaminant removal continues, this research introduces a biochar-supported ZnO hedgehog composed of nano-rods with a substantial specific surface area of 265 ± 0.2 m² g⁻¹. This feature significantly enhances its adsorption capacity and photocatalytic efficiency in the degradation of CEX. Experimental results indicate that the Langmuir adsorption model accurately describes the data, suggesting that adsorption predominantly occurs in a monolayer and follows a pseudo-second-order kinetic model. Photodegradation reaction rates of 2.70 × 10⁻² min⁻¹, 2.2 × 10⁻² min⁻¹, and 1.8 × 10⁻² min⁻¹ demonstrate the material’s high photocatalytic efficiency, reinforcing its potential as a viable solution for treating antibiotic-contaminated water.