Magnetic CoFe2O4 nanoparticles supported on graphene oxide (CoFe2O4/GO) with high catalytic activity for peroxymonosulfate activation and degradation of rhodamine B.

Rida Tabit,Abdallah Rhihil,Othmane Amadine,Younes Essamlali,Karim Dânoun,Mohamed Zahouily

doi:10.1039/c7ra09949e

Abstract

Herein, we report the preparation of magnetic CoFe2O4 nanoparticles and CoFe2O4/graphene oxide (GO) hybrids and evaluate their catalytic activity as heterogeneous peroxymonosulfate (PMS) activators for the decomposition of rhodamine B. The surface morphologies and structures of both CoFe2O4 nanoparticles and CoFe2O4/GO hybrids were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption–desorption isotherms. The magnetic properties of the samples were assessed using a SQUID magnetometer at 298 K. Catalytic oxidation experiments demonstrated that CoFe2O4/GO hybrids exhibited much better catalytic activity than CoFe2O4 nanoparticles or CoFe2O4/reduced graphene oxide (rGO) hybrids, suggesting that GO plays an important role in CoFe2O4/GO hybrids in the decomposition of rhodamine B. The influence of various reaction conditions such as temperature, concentration of PMS, pH and decomposition time of rhodamine B over the CoFe2O4/GO catalyst were investigated and optimized. The rhodamine B degradation process was found to fit a pseudo-first order kinetics model. The catalyst could be easily separated from the reaction mixture by applying an external magnet. In particular, the as-prepared CoFe2O4/GO hybrid exhibited good reusability and stability in successive degradation experiments in PMS solution.

Highlights

The dye industry discharges large amounts of industrial wastewater and it is one of the major sources of organic pollutants
We report a facile approach for preparing magnetic CoFe2O4 nanoparticles, CoFe2O4/reduced graphene oxide and CoFe2O4/graphene oxide (GO) and their catalytic performance toward activating PMS for the removal of rhodamine B
Cobalt and iron within CoFe2O4/GO were determined by inductively coupled plasma atomic emission spectroscopy (ICPAES) from Jab in Yvan and the carbon content was determined by a carbon/sulfur analyser (C.A) using HORIBA EMIA-320V2

Summary

Introduction

Sulfate radical-based oxidation processes have received much attention[4] for its efficient degradation of organic contaminants. The sulfate radical (SOc4À) generated from peroxymonosulfate, as an alternative to the hydroxyl radical (OHc), is a strong oxidant with a high redox potential It can react with many organic contaminants to yield a degradation performance similar to that expected for the hydroxyl radical (OHc). The Co2+ ion coupled with a PMS system for the degradation of organic contaminants has attracted tremendous interest since it exhibits better efficiencies than the Fenton reaction.[8,9] Despite the advantages of this homogeneous activation process, the application of this method in water treatment is limited due to. The catalytic activities of all prepared samples were investigated in terms of the reaction kinetics, reaction temperature, concentration of RhB and catalytic stability

Materials

Characterization

Catalytic test procedure

Results and discussion

Conclusion