Magnetic recyclable Co-MOF derivate-modified steel slag for tetracycline removal by integrated adsorption and Fenton-like catalysis

As a category of emerging pollutants, the wide occurrence of antibiotics in water bodies has adverse effects on aquatic organisms. Herein, a Co-MOF derivate-modified magnetic steel slag (MSS@Co-CN) was fabricated and used to remove tetracycline hydrochloride (TCH), a representative antibiotic, from wastewater by the synergistic effect of adsorption and Fenton-like oxidation. MSS@Co-CN exhibited a high adsorption capacity (q(max) > 416.6 mg/g) and a strong Fenton-like catalytic oxidation capacity for TCH (80 % removal efficiency within 5 min) by activating peroxymonosulfate (PMS) in a wide pH range (pH = 2-11). The TCH adsorption on MSS@Co-CN, with equilibrium reached within 30 min, was proved to be an exothermic multilayer adsorption process by the Freundlich and Temkin models. It also exhibits excellent stability of catalytic activity in five adsorption-oxidation cycles. The superoxide anion radicals and singlet oxygen were the main active species in the Fenton-like reaction. The concentration of leaching iron ion (0.03 mg/L, far below the standard for surface water) after the reaction was significantly reduced after Co-CN modification. Furthermore, the good magnetic property of MSS@Co-CN makes it easily separatable from water, showing good application potential. This work is expected to provide insight into the fabrication of highly efficient catalysts for antibiotic removal by the synergistic effect of adsorption and Fenton-like catalysis.