The occurrence of pharmaceutical contaminants in wastewater poses an obstacle to aquatic ecosystems and human health due to their persistence and potential health hazard. Naproxen (NPX), a carboxylate-based and piroxicam (PIR), a non-carboxylate-based drug, are utilized non-steroidal anti-inflammatory drugs (NSAIDs) commonly found in wastewater. Therefore, the advancement of effective approaches for removing such pollutants is critical. In this study, a novel photocatalyst, magnetic FeAl2O4-modified activated carbon (MAC-WS II), derived from walnut shell (WS), was hydrothermally synthesized from acid-treated walnut shell for NPX and PIR removal. MAC-WS II demonstrated near-complete degradation efficiencies of 99.15 and 98.49% for NPX and PIR after 45 min, respectively, attributed to synergistic mechanism, integrating adsorption, photocatalysis and photo-Fenton process, which facilitated rapid charge transfer and effective electron-hole separation, as confirmed by UV-Vis DRS, photoluminescence (PL) and electrochemical characterization. The kinetics of the synergistic reaction represented enhancements of 8.80 and 2.16-fold for PIR, and 13.39 and 2.33-fold for NPX, compared to adsorption alone and photocatalysis with adsorption, respectively. Furthermore, the rate constants of MAC-WS II were 2.74 times higher for PIR and 6.66 times higher for NPX compared to AC-WS II, indicating the important role of iron active centers in enhancing photocatalytic performance. Radical scavenging experiments demonstrated that superoxide (•O2−) and hydroxyl (•OH) radicals act as the primary reactive species responsible for PIR degradation, whereas •O2− together with photogenerated electrons (e−) play the dominant role in NPX degradation. Moreover, the results indicated that the relative contribution of •O2− and •OH varies between the photocatalysis and photo-Fenton reactions. Additionally, MAC-WS II retained 90.1 and 87.07% removal efficiency for PIR and NPX, respectively after five cycles, with negligible Fe and Al leaching after seven days of immersion in different solutions, confirming its structural and chemical stability. These findings establish MAC-WS II as an effective photocatalyst for the removal of pharmaceutical contaminants from wastewater, offering a promising route for sustainable water remediation.

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