A Novel Reduced Graphene Oxide-Attapulgite (RGO-ATP) Supported Fe2O3 Catalyst for Heterogeneous Fenton-like Oxidation of Ciprofloxacin: Degradation Mechanism and Pathway

Abstract

Ciprofloxacin, a third-generation fluoroquinolones (FQs) antibiotic, is observed to increasingly pollute the environment. In this study, a three-dimensional reduced graphene oxide-attapulgite-based catalyst Fe2O3/RGO-ATP was prepared and used to analyze the degradation of ciprofloxacin in a heterogeneous Fenton reaction. The heterogeneous catalyst Fe2O3/RGO-ATP was prepared by a one-step hydrothermal method, and the samples were characterized using BET(Brunauer-Emmett-Teller) surface area, Raman spectroscopy, X-ray diffraction (XRD), Fourier infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effect of reaction time, temperature, pH, initial concentration, H2O2 dosage and reuse time on the degradation of ciprofloxacin by the catalyst Fe2O3/RGO-ATP was investigated. The optimum conditions of degradation of ciprofloxacin are observed to be 60 °C, pH 5, H2O2 concentration of 2.9724 mmol/L, and initial ciprofloxacin concentration of 50 mg/L. The catalyst could be reused several times with a decline in catalytic capacity. Fourier-transform ion cyclotron resonance mass spectrometer (FT) was also employed to study the degradation products of ciprofloxacin in the aqueous solution. The results show that the heterogeneous catalyst Fe2O3/RGO-ATP possessed an excellent ability for the catalytic degradation of ciprofloxacin. Direct hydroxyl oxidation is noted to be the main pathway of degradation of ciprofloxacin, and no defluorination reaction is observed during the degradation process.

Scalable Synthesis of Sm2O3/Fe2O3 Hierarchical Oxygen Vacancy-Based Gyroid-Inspired Morphology: With Enhanced Electrocatalytic Activity for Oxygen Evolution Performance

“…Figure c shows the spectrum of Fe 2p corresponding to two main peaks, the peak of Fe 2p 3/2 located at ∼715 eV that validates Fe 2p 3/2 and the peak of Fe located at ∼729 eV that represents Fe 2p 1/2 , which corresponds to the +2 oxidation state . The curve fitting method was used to resolve the spectrum broadness of the O 1s core level, and three Gaussian peaks were observed, as shown in Figure d.…”

Enhanced Heterogeneous Fenton-like Process for Sulfamethazine Removal via Dual-Reaction-Center Fe-Mo/rGO Catalyst

“…For rGO, the wide peak at 24° was designated as the characteristic plane of the graphite crystal structure. The peak of the rGO plane weakened in the Fe-Mo/rGO catalysts, indicating that the hybridization of Fe and Mo on the rGO plane resulted in a reduction in the expansion of the plane-to-layer spacing [ 21 ]. For the Fe/rGO catalyst, the Fe 3 O 4 diffraction peaks at 35.5°, 43.1°, and 62.6° were observed (JCPDS19-0629) [ 22 ].…”

Synthesis of CuO/GO-DE Catalyst and Its Catalytic Properties and Mechanism on Ciprofloxacin Degradation

“…Graphene oxide (GO) was prepared by the Hummers method [ 38 , 40 ]. A total of 1 g graphite powder and 1 g sodium nitrate were added into 60 mL concentrated sulfuric acid and stirred vigorously in a low-temperature water bath, then 6 g potassium permanganate was slowly added and stirred for 3 h. The reaction mixture was put into a water bath with a temperature of 35 °C and continuously stirred for 3 h, then 140 mL of deionized water was added and stirred at room temperature for 12 h. A total of 200 mL of deionized water was added into the mixed solution, then 20 mL of hydrogen peroxide was slowly added, stirred for 1 h and stood for 5 h. After the product was settled, it was washed with dilute hydrochloric acid, then washed with deionized water to neutral, and ultrasonic for 2 h at 100 Hz to obtain a viscous graphene oxide solution.…”

“…Metal oxides (Fe 2 O 3 , CeO 2 , CuO, etc.) can be employed as active components coated on catalyst supports because they have similar catalytic effects to Fe 2+ or Cu 2+ [ 38 , 39 ]; moreover, they are not easy to lose and can be used in a wide pH range. In this study, diatomaceous earth (DE) was modified by graphene oxide (GO) to improve the specific surface area and enhance surface capacity, and then the modified diatomite carrier was loaded with different active metal salts separately to screen the best active component (metal oxide) for CIP degradation.…”