Construction of a gelatin aerogel catalyst functionalized with LaCoO3 and g-C3N5 for efficient ciprofloxacin degradation via adsorption and peroxymonosulfate activation

Abstract

Three-dimensional porous gelatin-based aerogels functionalized with LaCoO3 and nitrogen-rich graphitic carbon nitride (g-C3N5) were successfully fabricated via a freeze-drying approach. Herein, the gelatin-based aerogels served as excellent adsorbents and catalysts activating peroxymonosulfate (PMS) to efficiently degrade ciprofloxacin (CIP) from aqueous solutions. In comparison to the pristine gelatin aerogel (GA), the optimized functionalized aerogel (GA–LCCN-1.5) demonstrated a 17.0% superior CIP adsorption performance. Remarkably, GA–LCCN-1.5 exhibited 95.7% removal efficiency for CIP, attributed to the effective generation of •OH, SO4•−, and 1O2 via PMS activation. In addition, high degradation efficiencies over 84.1% were maintained throughout a broad pH range of 3–9. Notably, GA–LCCN-1.5 demonstrated outstanding stability and reusability, with 93.2% CIP removal efficiency even after five reuse cycles indicating significant promise in real applications. Radical quenching and electron spin resonance (ESR) analysis suggest that CIP degradation was dominated by radical and non-radical routes through GA–LCCN-1.5 catalyzed PMS decomposition. Besides, the plausible CIP degradation mechanisms were systemically analyzed and proposed. The toxicities of CIP and the intermediate by-products were evaluated and reported. The findings of this study and insights demonstrate a facile construction of a biopolymer-based aerogel catalyst for synergistic and efficient PMS activation for the removal of antibiotics in water.