Photo-fenton refreshable Fe3O4@HCS adsorbent for the elimination of tetracycline hydrochloride

A yolk–shell-structured sphere composed of a superparamagnetic Fe 3 O 4 core and a carbon shell (Fe 3 O 4 @HCS) was etched from Fe 3 O 4 @SiO 2 @carbon by NaOH, which was synthesized through the layer-by-layer coating of Fe 3 O 4 . This yolk–shell composite has a shell thickness of ca. 27 nm and a high specific surface area of 213.2 m 2  g −1 . Its performance for the magnetic removal of tetracycline hydrochloride from water was systematically examined. A high equilibrium adsorption capacity of ca. 49.0 mg g −1 was determined. Moreover, the adsorbent can be regenerated within 10 min through a photo-Fenton reaction. A stable adsorption capacity of 44.3 mg g −1 with a fluctuation <10% is preserved after 5 consecutive adsorption–degradation cycles, demonstrating its promising application potential in the decontamination of sewage water polluted by antibiotics.