Comparison of different advanced oxidation processes for treatment of antibiotic aqueous solution

The study was undertaken to compare from technical and economic point of view the treatment of antibiotic aqueous solution containing amoxicillin, ampicillin, and cloxacillin by Fenton, photo-Fenton, TiO2 photocatalytic and UV/ZnO processes. The best operating conditions for treatment of antibiotic aqueous solution containing 104, 105 and 103 mg/L of amoxicillin, ampicillin, and cloxacillin, respectively were: Fenton process — COD/H2O2/Fe2+ molar ratio 1:3:0.30 and pH 3; photo-Fenton process — COD/H2O2/Fe2+ molar ratio 1:1.5:0.075 and pH 3; UV/TiO2/H2O2 process — TiO2 1 g/L, ambient pH ∼ 5 and H2O2 100 g/L; UV/ZnO process — ZnO 0.5 g/L and pH 11. All studied processes were able to degrade the antibiotics and improve biodegradability (BOD5/COD ratio), except for UV/ZnO process which did not improve biodegradability. Photo-Fenton process exhibited higher rate constant (0.029 min− 1) than that of Fenton process (0.0144 min− 1) and this may be ascribed to photochemical regeneration of Fe2 + ions by photoreduction of Fe3 + ions and hence increasing hydroxyl radical production rate. Rate constants of UV/ZnO process (0.00056 min− 1) and UV/TiO2/H2O2 process (0.0005 min− 1) were lower than that of Fenton and photo-Fenton processes. Photo-Fenton process appeared to be the most cost-effective compared to the other studied processes.