Abstract
The presence of antibiotics in aquatic environments has attracted global concern. Fenton process is an attractive yet challenging method for antibiotics degradation, especially when such a reaction can be conducted at neutral pH values. In this study, a novel composite Fe/Co catalyst was synthesized via the modification of steel converter slag (SCS) by salicylic acid–methanol (SAM) and cobalt nitrate (Co(NO3)2). The catalysts were characterized by N2-Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results indicated that the Co-SAM-SCS/H2O2 Fenton-like system was very effective for sulfamethazine (SMZ) degradation at a wide pH range. At initial pH of 7.0, the degradation rate of SMZ in Co-SAM-SCS/H2O2 system was 2.48, 3.20, 6.18, and 16.21 times of that in Fe-SAM-SCS/H2O2, SAM-SCS/H2O2, Co(NO3)2/H2O2 and SCS/H2O2 system, respectively. The preliminary analysis suggested that high surface area of Co-SAM-SCS sample and synergistic effect between introduced Co and SAM-SCS are responsible for the efficient catalytic activity. During the degradation, three main intermediates were identified by high performance liquid chromatography–mass spectrometry (HPLC–MS) analysis. Based on this, a possible degradation pathway was proposed. The SEM images, XRD patterns and XPS spectra before and after the reactions demonstrate that the crystal and chemical structure of Co-SAM-SCS after five cycles are almost unchanged. Besides, the Co-SAM-SCS presented low iron and cobalt leaching (0.17 mg/L and 2.36 mg/L, respectively). The studied Fenton-like process also showed high degradation of SMZ in river water and municipal wastewater. The progress will bring valuable insights to develop high-performance heterogeneous Fenton-like catalysts for environmental remediation.
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•The preparation of a novel Fenton-like catalyst (Co-SAM-SCS) was studied.•Co-SAM-SCS/H2O2 system can work efficiently at slightly basic pH conditions.•The completely removal of 50 mg/L of SMZ has been achieved in 4 h.•HO.• are mainly responsible for the degradation of sulfamethazine (SMZ).•This system is found to be stable and efficient for several repeated cycles.