EDTA-based Fenton's and photo Fenton’s oxidation of ciprofloxacin using a potential iron catalyst Bioschwertmannite

<b>ABSTRACT</b>The study investigated bioschwertmannite's potential as an iron catalyst in Fenton's and Photo-Fenton's oxidation of ciprofloxacin with EDTA near neutral pH. Bioschwertmannite, an iron oxyhydroxy sulphate mineral, was synthesised using <i>Acidithiobacillus ferrooxidans</i>. This work presents a novel approach by utilising biologically synthesised schwertmannite as a heterogeneous catalyst for the degradation of ciprofloxacin, addressing the need for sustainable and cost-effective treatment methods. The catalytic role of bioschwertmannite in the degradation of ciprofloxacin was examined with various parameters, including catalyst dose (0.1-1 g/L), H₂O₂ concentration (100-1000 mg/L), pH values (3, 5, 7, and 9), initial ciprofloxacin concentrations (1-10 mg/L), and EDTA concentrations (10-100 mM). The maximum removal efficiency, around 99.16%, was achieved using Photo-Fenton's Oxidation utilising 0.5 g/L of bioschwertmannite and 500 mg/L of H₂O₂, in the presence of EDTA, resulting in a rate constant of 0.0357/min. Fenton's oxidation exhibits 82% degradation at identical conditions, with a rate constant of 0.0129/min. The degradation efficiency improved with increasing H₂O₂ concentration, reaching a maximum with oxidising agent concentration of 500 mg/L, beyond which a scavenging effect was seen. Increasing bioschwertmannite dosage from 0.1 to 0.5 g/L enhanced degradation by 14.5%. Results indicate that bioschwertmannite has favourable properties as an iron catalyst for the oxidation of ciprofloxacin with EDTA at near-neutral pH.