Preparation and characterization of carbon nanotubes/pyrite nanocomposite for degradation of methylene blue by a heterogeneous Fenton reaction

Carbon nanotubes/pyrite (CNTs/FeS2) nanocomposite was prepared by the co-precipitation of ferrous and ferric salts in presence of CNTs and subsequent sulfuration treatment of the prepared carbon nanotubes/iron oxide (CNTs/Fe3O4) material with elemental sulfur. The resulting nanocomposite was well characterized using FE-SEM, TEM, XRD, EDS and TGA techniques. The CNTs/FeS2 nanocomposite was employed as a heterogeneous catalyst for degradation of methylene blue (MB) dye in aqueous solution. The influence of reaction conditions including the hydrogen peroxide (H2O2) amount, hydroxylamine (NH2OH) amount, initial pH value and catalyst dosage on the dye degradation were studied. The degradation efficiency of MB (100 mg L-1) was up to 99.5% when the pH value, H2O2 amount, NH2OH amount and catalyst dosage were 3.0, 200 mu L, 60 mg and 0.2 g, respectively. Beside, the positive effect of NH2OH on MB degradation is caused by the acceleration of Fe3+ ions reduction and enhancement the oxidation reactivity in the Fenton system. The reusability of the catalyst was also studied after six successive cycles. In addition, an oxidation mechanism of MB by the present Fenton process was proposed. The present system has advantages on the viewpoint of high degradation performance, no sludge formation, short reaction time and catalyst reusability. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.