Sulfonic acid metal-organic frameworks derived iron-doped carbon as novel heterogeneous electro-Fenton catalysts for the degradation of tetracycline: Performance and mechanism investigation

Designing efficient heterogeneous electro-Fenton (HEF) catalysts for in-situ H2O2 generation and organic pollutant degradation in water has become a hot research topic. In this study, a series of novel UiO-66-SO3H/Fe(x)-800 materials were successfully prepared by carbonizing sulfonic acid metal-organic frameworks (UiO-66-SO3H) doped with iron for tetracycline (TC) HEF degradation. The catalytic performance of UiO-66-SO3H/Fe(x)-800 was evaluated by comparing different HEF systems, and the effects of different operating parameters and co-existing substances were investigated. The results indicated that UiO-66-SO3H/Fe(1:1)-800 displayed excellent performance for TC degradation over a broad pH range, with an optimal TC degradation efficiency of 90.10% in 90 min and a low energy consumption of 4.39 kWh/kg/TOC. Furthermore, the superior stability and reusability of this catalyst were proved in continuous cycling experiments with low iron leaching (<1.000 ug/L). The mechanism exploration demonstrated that TC was mainly oxidized by ‧OH and 1O2. In addition, iron-doped porous carbon carrier improved the utilization rate of H2O2 and accelerated the regeneration of Fe2+, which played an important role in the HEF process. The HEF system based on UiO-66-SO3H/Fe(1:1)-800 also exhibited satisfactory performance when treating actual water samples, presenting broad application prospects.