Oxidation–coagulation of β-blockers by K2FeVIO4 in hospital wastewater: Assessment of degradation products and biodegradability

This study investigated the degradation of atenolol, metoprolol and propranolol beta-blockers by ferrate (K2FeO4) in hospital wastewater and in aqueous solution. In the case of hospital wastewater, the effect of the independent variables pH and [Fe(VI)] was evaluated by means of response surface methodology. The results showed that Fe(VI) plays an important role in the oxidation–coagulation process, and the treatment of the hospital wastewater led to degradations above 90% for all the three β-blockers, and to reductions of aromaticity that were close to 60%. In addition, only 17% of the organic load was removed. In aqueous solution, the degradation of the β-blockers atenolol, metoprolol and propranolol was 71.7%, 24.7% and 96.5%, respectively, when a ratio of 1:10 [β-blocker]:[Fe(VI)] was used. No mineralization was achieved, which suggests that there was a conversion of the β-blockers to degradation products identified by liquid chromatography/mass spectrometry tandem. Degradation pathways were proposed, which took account of the role of Fe(VI). Furthermore, the ready biodegradability of the post-process samples was evaluated by using the closed bottle test, and showed an increase in biodegradability. The use of the ferrate advanced oxidation technology seems to be a useful means of ensuring the remediation of hospital and similar wastewater.

► Degradation of β-blockers by Fe(VI) in real hospital wastewater.
► Fe(VI) oxidized more than 90% of the β-blockers and reduced the aromaticity by 60%.
► 34 different degradation products were identified by means of LC-ESI-IT-MS.
► Degradation pathways were charted for atenolol, metoprolol and propranolol.
► The oxidation–coagulation increased the ready biodegradability of atenolol and propranolol.