Peroxyacetic acid activated sulfite process: Generation of reactive species and degradation of β-lactam antibiotics

Sulfite advanced oxidation process is a new chemical oxidation technology with strong development potential and can effectively produce many reactive species for the degradation of emerging contaminants (ECs). This study used the peracetic acid activated sulfite advanced oxidation process (PAA/S(IV) process) with no additional energy input and no heavy metal used to degrade typical β-lactam antibiotics. 79.68 % of amoxicillin (AMX) was rapidly degraded in the PAA/S(IV) process within 5 min, and the reaction pH of 7.0∼9.0 is the best degradation effect. In the PAA/S(IV) process, SO₄^•-, •OH and CH₃C(O)OO• that degrade AMX can be produced, and the contribution rates to the AMX degradation were 58.80 %, 22.24 %, and 18.96 %, respectively. The presence of HCO₃^– and HA cleared •OH and SO₄^•- affected the formation of CH₃C(O)OO• and then delayed the AMX degradation, while the effect of Cl^- on the AMX degradation was negligible. Under the action of the reactive species, the β-lactam ring is broken, and five degradation paths are proposed.