Photodegradation of Penicillin Antibiotics in Aqueous Solutions

The degradation kinetics of penicillin antibiotics, using amoxicillin (AMX) as an example, was studied in photoinitiated double oxidant systems {UV/H 2 O 2 /S 2 O ₈^2 - } and {UV/H 2 O 2 /S 2 O ₈^2 - /Fe 2+ } under UV radiation from a KrCl* excilamp (λ = 222 nm). The optimal conditions for the oxidative degradation of AMX in the {UV/H 2 O 2 /S 2 O ₈^2 - } system are achieved at an equimolar ratio of the oxidants. Combined activation of the oxidants by iron ions and UV radiation of the excilamp in the {UV/H 2 O 2 /S 2 O ₈^2 - /Fe 2+ } system at [Fe 2+ ] = 0.1 mM led to high mineralization of total organic carbon (TOC) of up to 55% along with complete degradation of AMX, and a synergistic effect was established. The components of the real water matrix have an inhibitory effect on the processes of AMX degradation and TOC mineralization in the double oxidant systems; however, the degree of their influence is lower than in the mono oxidant systems. The results indicate that the {UV/H 2 O 2 /S 2 O ₈^2 - } and {UV/H 2 O 2 /S 2 O ₈^2 - /Fe 2+ } double oxidant systems are promising for the degradation of antibiotics to reduce their release into the environment, and they also show the necessity for further research.