Dong Wan

Degradation of p-Nitrophenol using magnetic Fe0/Fe3O4/Coke composite as a heterogeneous Fenton-like catalyst

A Coke supported Fe3O4 and Fe0 composite (Fe0/Fe3O4/Coke) was prepared for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the Fenton degradation of p-Nitrophenol (p-NP). A four factor Box-Behnken design (BBD) coupled with response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely Fe0/Fe3O4/Coke dosage, reaction temperature, initial pH and H2O2 concentration, on the removal efficiency of p-NP. A significant quadratic model (p-value<0.0001, R2=0.9952) was derived using analysis of variance (ANOVA). Optimum conditions were determined to be 1.3g/L catalyst, 32°C, pH3.1 and 11.3mM H2O2. 100% of p-NP (100mg/L) conversion and 81% of COD removal were achieved after 120min of reaction time, respectively, under the optimum conditions, which agreed well with the modeling prediction. The recyclability of Fe0/Fe3O4/Coke was also investigated after three successive runs, in which p-NP degradation performances showed a slight difference with the first oxidation cycle with an acceptable iron leaching. Moreover, according to the main intermediate products identified by gas chromatography-mass spectrometry (GC-MS), a possible pathway of p-NP degradation was proposed based on hydrogen radicals ([H]) or hydroxyl radicals (•OH) mechanism.

Heterogeneous Fenton degradation of Orange II by immobilization of Fe3O4 nanoparticles onto Al-Fe pillared bentonite

A novel catalyst, Fe3O4 nanoparticle decorated Al-Fe pillared bentonite (Fe3O4/Al-Fe-P-B), was prepared by in situ precipitation oxidization method. The catalyst was characterized by SEM, XRD and Raman spectroscopy. The Fe3O4 nanoparticles mainly exist on the surface or enter into the pore of bentonite, with better dispersing and less coaggregation. The catalytic activity of Fe3O4/Al-Fe-P-B was investigated in the degradation of Orange II (OII) by heterogeneous Fenton-like process. The effects of initial concentration of hydrogen peroxide, catalyst loading, temperature and initial pH on the degradation of OII were investigated. The Fe3O4/Al-Fe-P-B showed higher degradation efficiency of OII than bare Fe3O4 or Al-Fe-P-B in the degradation experiment. The enhanced catalytic activity of Fe3O4/Al-Fe-P-B in heterogeneous Fenton system was due to the synergistic effect between Al-Fe-P-B and Fe3O4. The novel catalyst can achieve solid-liquid separation easily by sample magnetic separation and has a good reusability and stability.

Synthesis and characterization of biomimetic Fe3O4/coke magnetic nanoparticles composite material

A composite material (Fe3O4/Coke) using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemical oxidation precipitation method and characterized by SEM, XRD, Raman, and FTIR. The results showed that the Fe3O4 nanoparticles existed steadily on the surface of coke, with better dispersing and smaller particle size. The catalytic ability of Fe3O4/Coke were investigatied by degrading p-nitrophenol (P-NP). The results showed that the apparent rate constant for the P-NP at 1.0 g·L−1 catalyst, 30 mmol·L−1 H2O2, pH=3.0, 30 °C and the best ratio of Coke/Fe3O4 0.6, was evaluated to be 0.027 min–1, the removal rate of CODCr was 75.47%, and the dissolubility of Fe was 2.42 mg·L–1. Compared with pure Fe3O4, the catalytic ability of Fe3O4/Coke in the presence of H2O2 was greatly enhanced. And Fe3O4/Coke was a green and environmental catalyst with high catalytic activity, showing a good chemical stability and reusability.

Preparation and Adsorbability for Orange II of CTAB Modified Bentonite

Surfactant modified bentonite was prepared using cetyltrimethylammonium bromide (CTAB) by a simple ion exchange method, and the organification of bentonite was proved by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron micrographic (SEM). The adsorption of Orange II(OII) dye onto CTAB modified bentonite was carried out. Compared with natural bentonite, the adsorption capacity of CTAB-Bent for OII was greatly enhanced. The adsorption isotherm of OII was in good agreement with the Langmuir equation.

Visible light induced photocatalytic degradation of rhodamine B by magnetic bentonite.

The photocatalytic activity of magnetic bentonite, Fe3O4 nanoparticles decorated Al-pillared bentonite (Fe3O4/Al-B), for the degradation of rhodamine B (RhB) in the presence of H2O2 under visible light (VL) was evaluated. The effects of different reaction parameters such as catalyst dose, dye concentration and externally added H2O2 were also investigated. The magnetic bentonite showed good photocatalytic activity, magnetic separability and stability for repeated use. More than 95% of 40 mg/L RhB was converted within 3 h under VL with a catalyst dose of 0.5 g/L. Suitable mechanisms have been proposed to account for the photocatalytic activities in the presence and absence of H2O2. The efficiency of H2O2 in VL process was much higher than that of the dark process. Results obtained in the current study may be useful to develop a suitable photocatalyst for photocatalytic remediation of different water contaminants including organic dyes.

Synthesis of magnetically modified Fe-Al pillared bentonite and heterogeneous Fenton-like degradation of orange II

Magnetically modified Fe-Al pillared bentonite (Fe3O4/Fe-Al-Bent) was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous catalysts in the presence of H2O2. The experimental result indicated that the synthetic materials had a high catalytic activity and good reusability.

Synthesis of Magnetic Modified Organobentonite as Adsorbent for Degradation of Orange II

Magnetic modified organobentonite (Fe3O4/CTAB–Bent) was synthesized by chemical co-precipitation method in which CTAB–Bent was firstly achieved via ion–exchange.The composite materials have been characterized by powder X–ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and Scanning electron microscopy (SEM) . The results revealed that basal spacing of bentonite was increased through organic modification and the Fe3O4 particles synthesized which covering the surfaces of bentonite .Compared with natural bentonite, the adsorption capacity of Fe3O4/CTAB–Bent for Orange II was greatly enhanced and can be easily separated from the reaction medium by an external magnetic field after the treatment.

Synthesis and Catalysis of Fe3O4 Nanoparticles for Degradation of Rhodamine B

Fe3O4 nanoparticles (Fe3O4 NPs) were successfully prepared via chemical co-precipitation method under the assistance of ultrasound irradiation and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). a series of experiments were carried out to investigate the degradation of Rhodamine B(RhB) by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The effects of catalyst loading,initial pH, reaction temperature, oxidant concentration were discussed. The result indicated that the optimal conditions were Fe3O4 NPs dosage 0.7 g/L, initial pH=3.0, reaction temperature 60°C, oxidant concentration 20 mmol /L.