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

A yolk-shell-structured sphere composed of a superparamagnetic Fe3O4 core and a carbon shell (Fe3O4@HCS) was etched from Fe3O4@SiO2@carbon by NaOH, which was synthesized through the layer-by-layer coating of Fe3O4. 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.