MOF-derived three-dimensional flower-like FeCu@C composite as an efficient Fenton-like catalyst for sulfamethazine degradation

Abstract

In this paper, a novel three-dimensional flower-like Fenton-like catalyst with iron-copper bimetallic NPs within the mesoporous carbon shell (FeCu@C) was successfully prepared through a simple pyrolysis of a [Fe,Cu]-BDC precursor and applied for catalytic degradation of sulfamethazine (SMT) in the presence of H2O2. The FeCu@C catalyst showed a 100% SMT removal within 90 min and a 72.3% total organic carbon (TOC) conversion within 240 min under the conditions of 20 mg L−1 SMT, 0.25 g L−1 FeCu@C, 1.5 mM H2O2, and initial solution pH 3.0. Combined with the characterization results, we proposed that the unique structure and composition of FeCu@C enable the catalyst to exhibit outstanding adsorption capability and catalytic performance in SMT degradation by H2O2 activation. The porous flower-like carbon matrix not only favors the rapid diffusion of reactants towards the internal bimetallic nanoparticles (NPs), but also offers specific adsorption for the enrichment of SMT molecules from bulk solution through π − π interaction. In addition, the iron and copper species existing in the inner bimetallic NPs are available active sites for a Fenton reaction, and a possible synergistic effect between them could facilitate the generation of additional OH radicals to enhance SMT degradation. Moreover, the accumulation (i.e. adsorption) of SMT molecules on the surface of FeCu@C could increase their contact probability with the OH radicals generated from H2O2 decomposition, further enhancing the reaction efficiency. With its high-magnetization properties, FeCu@C can be magnetically recovered and reused in SMT degradation. Furthermore, the possible reaction mechanism of the FeCu@C/H2O2 system and SMT degradation pathways were also tentatively proposed.