In this study, the CuCoFe-layered double hydroxide was employed for the degradation of glyphosate in water via peroxymonosulfate (PMS) activation. Scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller analyses were used to characterize the material. The effects of the catalytic system, initial solution pH, and catalyst and PMS dose on the degradation efficiency of glyphosate were investigated. The results indicated that after 6 min the CuCoFe-LDH/PMS system can degrade 99.54 % of glyphosate (100 mg/L) using 100 mg/L of CuCoFe-LDH, 200 mg/L of PMS, and pH 11. In addition, radical quenching experiments prove that the reactive oxygen species (e.g., SO 4 ●- , HO ● , O 2 ●– , and 1 O 2 ) are formed and SO 4 ●- plays a decisive role in glyphosate degradation. Moreover, the CuCoFe-LDH catalyst is reusable and stable with a glyphosate removal efficiency of 90.34 % after five continuous degradation cycles.
Nguyen Quang Tung,Do Thi Cam Van,Dam Xuan Thang,Nguyen Thi Kim An,Tran Thi Trang,Bui Dinh Nhi,Nguyen Phuong Thao,Le The Son,Nguyen Nhat Huy,Nguyen Trung Dung
In this study, the CuCoFe-LDH catalyst was synthesized by hydrothermal method and applied to degrade levofloxacin (LFX) by peroxymonosulfate (PMS) activation. The physicochemical properties of the synthesized samples were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The influence of various factors such as catalyst system, pH, catalyst content, PMS , pH, and coexisting ions on the degradation of LFX was systematically investigated. The results showed that after 10 min, 94.57 % of LFX was decomposed under the conditions of 200 mg/L of catalyst, 500 mg/L of PMS, 10 mg/L of LFX, and pH 7.0. Besides, the CuCoFe-LDH/PMS system can effectively remove LFX over a wide pH range from 3.5 to 9.0. Both radical superoxide (O 2 •- ) and non-radical singlet oxygen ( 1 O 2 ) were major reactive oxygen species in the CuCoFe-LDH/PMS system. Mass spectrometry identified 16 major degradation products of LFX, and 38.43 % of LFX was mineralized after 30 min of reaction. Besides, the CuCoFe-LDH/PMS system had the ability to effectively degrade different groups of antibiotics (e.g., fluoroquinolone, tetracycline , and sulfonamide). The mechanism of PMS activation by CuCoFe-LDH and the LFX degradation pathway were proposed. Finally, testing the reusability of CuCoFe-LDH in LFX degradation showed that a decrease of nearly 7 % occurred after five consecutive cycles, suggesting its stability for practical applications.
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