Data for: Synthesis and assessment of schwertmannite/few-layer graphene composite for the degradation of sulfamethazine in heterogeneous Fenton-like reaction

Schwertmannite, an iron oxyhydrosulfate mineral, can catalyze Fenton-like reaction to degrade organic contaminants, but the reduction of Fe(III) to Fe(II) on the surface of schwertmannite is a limiting step for the Fenton-like process. In the present study, the schwertmannite/few-layer graphene composite (sch-FLG) was synthesized to promote the catalytic activity of schwertmannite in Fenton-like reaction. It was found that schwertmannite can be successfully carried by FLG in sch-FLG composite, mainly via the chemical bond of Fe-O-C on the surface of sch-FLG. The sch-FLG exhibited a much higher catalytic activity than schwertmannite or FLG for the degradation of SMT in the heterogeneous Fenton-like reaction, which resulted from that the few-layer graphene can pass electrons efficiently. The degradation efficiency of SMT was around 100% under the reaction conditions of H2O2 200-500 mg L-1, sch-FLG dosage 1-2 g L-1, temperature 28-38 °C, and initial solution pH 1-9. During the repeated uses of sch-FLG in Fenton-like reaction, it maintained a certain catalytic activity for the degradation of SMT and the mineral structure was not changed. In addition, SMT may be finally mineralized in Fenton-like reaction catalyzed by sch-FLG, and the possible degradation pathways were proposed. Therefore, the sch-FLG is an excellent catalyst for SMT degradation in heterogeneous Fenton-like reaction.

Methods
The morphology of sch-FLG was characterized by using high-resolution transmission electron microscopy (HRTEM, JEOL). The crystal structure of sch-FLG was characterized by using X-ray diffraction (XRD, Thermo Fisher XTRA) at a scanning rate of 10° min-1 in the 2θ range of 10-70° with Cu-Kα radiation (λ = 1.5406 Å) at room temperature. The surface elements of sch-FLG were characterized by using X-ray photoelectron spectroscopy (XPS, Thermo Scientific ESCALAB 250Xi) system with Al Kα radiation (Energy 1486.6 eV). The Brunauer-Emmett-Teller (BET) specific surface area and Barret-Joyner-Halenda (BJH) pore volume of sch-FLG were measured by using N2 adsorption-desorption method (Tristar 3000, Micromeritics). The chemical structure of sch-FLG was characterized by using the Fourier transform infrared (FTIR, Thermo Nicolet 6700), and the samples were prepared with the powder pressing method in KBr pellet at room temperatu