A green method on dipole solvent as “Activators”: γ-valerolactone/H₂O system promoted degradation of ciprofloxacin by ferrate(Ⅵ)

This paper investigates the efficient degradation of ciprofloxacin (CIP) in a sustainable γ-valerolactone (GVL) and water (H₂O) mixed system by controlling proton transfer and reducing the self-decay rate of Fe(VI). The kinetic model reveals that the GVL/H₂O system exhibits a rate constant of (9.7 ± 0.7) × 10 M⁻¹ s⁻¹, significantly higher than the (6.8 ± 0.5) × 10 M⁻¹ s⁻¹ observed in pure H₂O. Furthermore, the self-decay rate decreases from (3.1 ± 0.4) × 10⁻² s⁻¹ in H₂O to (1.4 ± 0.2) × 10⁻² s⁻¹ in the GVL/H₂O system. The role of Fe(IV)/Fe(V) in the degradation process was confirmed using dimethyl sulfoxide (DMSO). Dynamic light scattering (DLS) results indicated that GVL could confine water clusters within the range of 1.69–3.68 nm. Density functional theory (DFT) and theoretical calculations demonstrated that the nucleophilic site of CIP in the GVL/H₂O system shifted to the carboxyl group. The toxicity analysis of the degradation products underscored the significance of CIP transfer treatment. This study highlights using the green water treatment agent Fe(VI) and the biodegradable solvent GVL to effectively reduce environmental impact, presenting significant potential for environmental pollution control.