A comparative study on Fe(III)/H2O2 and Fe(III)/S2O82− systems modified by catechin for the degradation of atenolol.

The processes of Fe(III) activated persulfate (PS) and H 2 O 2 modified by catechin (CAT) had been shown to be effective in degrading contaminants. In this study, the performance, mechanism, degradation pathways and products toxicity of PS (Fe(III)/PS/CAT) and H 2 O 2 (Fe(III)/H 2 O 2 /CAT) systems were compared using atenolol (ATL) as a model contaminant. 91.0% of ATL degradation was reached after 60 min in H 2 O 2 system which was much higher than that in PS system (52.4%) under the same experimental condition. CAT could react directly with H 2 O 2 to produce small amounts of HO• and the degradation efficiency of ATL was proportional to CAT concentration in H 2 O 2 system. However, the optimal CAT concentration was 5 μM in PS system. The performance of H 2 O 2 system was more susceptible to pH than that of PS system. Quenching experiments were conducted indicating that SO 4 •- and HO• were produced in PS system while HO• and O 2 •- accounted for ATL degradation in H 2 O 2 system. Seven pathways with nine byproducts and eight pathways with twelve byproducts were put forward in PS and H 2 O 2 systems respectively. Toxicity experiments showed that the inhibition rates of luminescent bacteria were both decreased about 25% after 60 min reaction in two systems. Although the software simulation result showed few intermediate products of both systems were More toxic than ATL, but the amounts of them were 1–2 orders of magnitude lower than ATL. Moreover, the mineralization rates were 16.4% and 19.0% in PS and H 2 O 2 systems respectively. [Display omitted] • Comparative studies were done in Fe(III)/H 2 O 2 /CAT and Fe(III)/PS/CAT system. • The performance of ATL degradation was efficient in Fe(III)/H 2 O 2 /CAT system. • The ATL degradation rates were slightly affected by pH in Fe(III)/PS/CAT system. • Degradation pathways of ATL in two systems were proposed and compared. • Several byproducts showed less toxicity in two systems. [ABSTRACT FROM AUTHOR]