Degradation of Aqueous Tetracycline Hydrochloride through Radical-based Advanced Oxidation Processes Using UV 222 nm/S₂O₈²⁻ and UV 222 nm/H₂O₂

Abstract

This research investigated the effectiveness of UV 222 nm (UV222)/hydrogen peroxide (UV222/H₂O₂) and UV222/sulfate anion (UV222/S₂O₈²⁻) using a KrCl* excilamp (222 nm) in degrading tetracycline hydrochloride (TCH) antibiotics in water. The optimal production of hydroxy radicals occurred with a 0.05% H₂O₂ concentration in the UV222/H₂O₂ process. Additionally, UV222/H₂O₂ showed more significant degradation of organic dyes (methyl orange and methylene blue) compared to UV222 alone. Compared to UV222/H₂O₂, the processes involving UV222/S₂O₈²⁻ were found to be more effective in degrading methyl orange due to the prolonged half-life of sulfate radicals and their electron transfer mechanism. Similarly, the degradation of TCH was more efficient in UV222/S₂O₈²⁻ than in UV222/H₂O₂. The solution pH had minimal impact on TCH degradation in UV222/S₂O₈²⁻, while the presence of anions influenced the process. The degradation of TCH was not affected by Cl⁻ or SO₄²⁻, but it was enhanced by HPO₄²⁻. On the other hand, NO₃⁻ hindered TCH degradation. Additionally, in the UV222/S₂O₈²⁻ system, TCH degradation was three times greater in tap water than in deionized water. The UV222/S₂O₈²⁻ system showed potential for efficiently degrading TCH in real water samples, highlighting the applicability of UV222-based advanced oxidation processes in eliminating antibiotic contaminants from natural aqueous environments.