Heterogeneous sulfate radical-based advanced oxidation process for the efficient pharmaceutical wastewater treatment:...

Magnetic ferrospinel nanoparticles have significant advantages for the oxidative degradation of recalcitrant organic contaminants during wastewater treatment. In this study, a sulfate radical-based oxidation process was conducted using multiwalled carbon nanotubes (CNT) decorated with ferrospinel CoFe₂O₄ (CFO) nanoparticles to catalyze peroxydisulfate (PDS) for the efficient degradation of tetracycline (TC) and pharmaceutical wastewater. CNT played a critical role in enhancing the catalytic activity of CFO to activate PDS, enabling rapid degradation (100 %, k_obs = 0.347 min^-1) and mineralization (62.8 %) of TC (20 mg/L) within 30 min of catalytic oxidation. Recycling tests demonstrated the high stability of the as-prepared nanocomposite with minimal leaching of metal ions during the oxidation reactions. The degradation mechanism was elucidated, implying that both radical (HO^•, SO₄^•-, and O₂^•-) and non-radical (¹O₂) species contributed significantly to TC degradation over the CNT@CFO/PDS system. When combined with other chemical oxidants, CNT@CFO exhibits noticeable catalytic activity, indicating a high potential for application in the purification of pharmaceutical wastewater. This study develops a valuable insight into water purification through the integration of adsorption and catalytic oxidation advantages in PDS activation. The results of this study demonstrate a feasible and easy approach for the preparation of magnetically recoverable catalysts with exceptional efficacy, which can be used for the efficient decontamination of antibiotics in aqueous solutions.