Preparation of magnetic ZIF-8/reduced graphene oxide composite aerogels for efficient removal of ofloxacin†

Abstract

To solve the problem of ofloxacin pollution in contaminated water, Fe₃O₄ and ZIF-8 were prepared by a solvothermal method and stirring at normal temperature, respectively. Furthermore, a series of magnetic ZIF-8/reduced graphene oxide (Fe₃O₄/ZIF-8/rGO) composite aerogels with different mass ratios were synthesized by reduction and freeze-drying methods. The products were characterized using a Fourier transform infrared spectrometer, an X-ray diffractometer, a field emission scanning electron microscope, and a thermogravimetric analyzer. Taking ofloxacin (OFL) as the target pollutant, an orthogonal test was carried out to explore the optimum conditions for removing ofloxacin with the composite aerogel: under the conditions of an illumination time of 8.0 h, a mass ratio of 10 : 15 : 20 for Fe₃O₄/ZIF-8/rGO, a composite aerogel dosage of 8 mg, and an initial concentration of ofloxacin of 50 mg L⁻¹, the removal rate of ofloxacin reached 98.87%. After being recycled five times, the removal rate remained at 90.23%. The prepared Fe₃O₄/ZIF-8/rGO composite aerogel and the developed ofloxacin removal procedure could provide a reference for the treatment of quinolone antibiotics and PPCPs in polluted water. Moreover, they can be expected to alleviate the energy crisis and enhance the application of solar energy to deal with environmental remediation in the future.