Unraveling the synergistic effect of adsorption-photocatalysis in magnetically recyclable Fe3O4/metal-organic gels/sodium alginate beads for chlortetracycline hydrochloride elimination

The development of highly efficient and easily recyclable materials remains at the forefront of chlortetracycline hydrochloride (CTC) remediation. Herein, two magnetic metal-organic gels (Fe3O4/Fe-MOG and Fe3O4/Al-MOG) are constituted by an ultrafast room-temperature synthesis of MOGs on the surface of carboxylated Fe3O4, affording exceptional adsorption-photocatalysis abilities towards CTC under visible light irradiation, along with favorable magnetic separation capabilities. Meanwhile, the proposed synergistic mechanisms of adsorption-photocatalysis, the probable degradation pathways of CTC, and the underlying toxicity evaluation of intermediates are expounded. More importantly, we ingeniously develop Fe3O4/MOGs/SA beads with sodium alginate (SA) as the backbone and magnetic MOGs as the reaction center, which minimizes the loss of powdered Fe3O4/MOGs and ameliorates the recyclability. Attractively, Fe3O4/MOGs/SA beads achieve long-term continuous operation for CTC degradation in various water samples under visible light irradiation. Overall, this work highlights a new possibility for devising immobilized magnetic MOGs with adsorption-photocatalysis synergies in actual and large-scale wastewater remediation.