Sulfate radical-based oxidative degradation of acetaminophen over an efficient hybrid system: Peroxydisulfate decomposed by ferroferric oxide nanocatalyst anchored on activated carbon and UV light

In this work, a sulfate radical-based oxidation system was applied for degradation of acetaminophen (ACP) using peroxydisulfate (PDS) catalyzed by ferroferric oxide nanocatalyst (FON) coated on activated carbon (AC) (marked as FON@AC) and UV light. Textural, structural and physico-chemical properties of FON@AC catalyst were characterized by using XRD, BET, TEM, FESEM-EDS and VSM techniques. Tentative mechanisms of PDS activation and ACP degradation were also proposed. Results indicated a significant synergistic effect into ACP degradation for FON@AC coupled with UV and PDS. At optimum conditions (pH: 6.0, 0.4 g/L FON@AC, 4.0 mM PDS), the complete ACP (20 mg/L) and 72.8% of TOC were removed within 60 min reaction over FON@AC/PDS/UV system. A high potential for FON@AC into decomposition of three types of oxidants (PDS, peroxymonosulfate and H2O2) was also observed. An excellent durability was found for FON@AC, because the amount of leached Fe was negligible. After five consecutive degradation cycles, the elimination efficiencies of ACP and TOC were still above 84 and 54%, respectively. Kinetic behavior of ACP degradation followed the pseudo-first-order reaction model. As compared to other studies anions, the strongest suppression effect on ACP degradation was assigned to chloride ions. According to quenching tests, SO4 center dot- and HO center dot played an important role in the ACP degradation during FON@AC/PDS/UV process. Particularly, FON@AC/PDS/UV hybrid system can be introduced as an effective treatment process, thanks to good stability and recyclability, easy recovery, high catalytic activity in degradation and mineralization of organics.