MXene-supported MIL-88A(Fe) as persulfate activator for removal of tetracycline

Abstract The poor conductivity, poor stability and agglomeration of MIL-88A(Fe) limit its application as persulfate (PS) activator in water purification. Herein, MXene-supported MIL-88A (Fe) composites (M88A/MX) were synthesized to enhance its adsorption and catalytic capability for tetracycline (TC) removal. M88A/MX-0.2 composites exhibits optimal degradation efficiency，reaching 98% under conditions of 0.2 g/L M88A/MX-0.2, 1.0 mM PS, 20 ppm TC, and pH 5. The degradation rate constants of M88A/MX-0.2 was 0.03217 min-1, which was much higher than that of MIL-88A(Fe) (0.00159 min-1) and MXene (0.00626 min-1). The removal effects of reaction parameters, such as dosage of M88A/MX-0.2 and PS, initial solution pH and the presence of the common co-existing constituents (humic acid and the inorganic anions) were investigated in detail. Additionally, the reuse of M88A/MX-0.2 showed that the composites had good cycling stability. The results of electron paramagnetic resonance (EPR) and quenching experiments indicated that ·OH, ·SO4- and ·O2- were involved in the M88A/MX-0.2/PS system. This study offered a new avenue for sulfate-based degradation of Fe-based metal organic framework.