ABSTRACT
In the present work, mesoporous silica spheres-doping CuO (CuO/MSS) was prepared via a facile hydrothermal method. It acted as a peroxydisulfate (PDS) activator for the removal of bisphenol A (BPA). X-Ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) showed that CuO was successfully synthesized and silica spheres were doped in CuO. Nitrogen sorption isotherm showed that CuO/MSS, which had a high specific surface area and a narrow pore size distribution, exhibited a mesoporous structure. The effect of initial pH, PDS dosage, catalyst amount, and activation temperature was assessed. A removal efficiency of over 80% was observed after five consecutive cycles, suggesting the superior stability of the catalyst. X-ray photoelectron spectroscopy (XPS), radical quenching experiments, and electrochemical evaluation showed that BPA removal was dominated by the electron transfer among PDS, BPA, and the surface of CuO/MSS (non-radical pathway), while SO4·- and OH· radicals had a minor contribution (radical pathway). In addition, the degradation pathways of BPA were proposed according to the intermediates. Overall, this study indicates that CuO/MSS is a promising effective PDS activator to address the drawbacks of the classical Fenton process.
Subject(s)
Benzhydryl Compounds , Silicon Dioxide , Copper , PhenolsABSTRACT
Compared with natural enzymes, artificial mimic enzymes have been widely studied for their high stability and cost effectiveness. In this study, CuSe nanoplates as a simulated enzyme which does not contain precious metals, has peroxidase activity. CuSe nanoplates were prepared and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectrometer (EDS). Kinetic studies show that CuSe nanoplates exhibits a higher affinity for 3,3',5,5'-teramethylbenzidine (TMB) than horseradish peroxidase (HRP). The rapid colorimetric determination of H2O2 and L-cysteine were developed based on the catalytic efficiency. The linear range of detection for H2O2 is 5.0×10-6~8.0×10-5 M, and the detection limit is 2.9×10-6 M, while the relative standard error is less than 5%. In addition, L-cysteine was detected with a detection limit of 0.2×10-6 M. The good selectivity of the determination to H2O2 and L-cysteine in aqueous solution was also achieved. CuSe nanoplates as a simulated enzyme for sensor applications would be used in environmental monitoring and biomedical analysis.
