Enhanced adsorption and catalytic degradation of organic dyes by nanometer iron oxide anchored to single-wall carbon nanotubes

Abstract

Abstract Arc discharge method with Fe catalyst was used to prepare single-wall carbon nanotubes (SWCNTs) and there are an amount of iron nanoparticles formed tightly on SWCNTs. Nanometer iron oxide anchored to SWCNT composite (AO-Fe-SWCNTs) was obtained in situ by oxidizing the above as-grown SWCNTs (As-Fe-SWCNTs) in air at 375 °C. AO-Fe-SWCNTs exhibited an excellent performance of adsorption, Fenton and photo-Fenton degradation of methyl blue (MB) and methyl orange (MO) in aqueous solutions. Adsorption of MB and MO by AO-Fe-SWCNTs could reach equilibrium within 10 min and its maximum adsorption capacity for MB and MO was up to 256.69 mg g−1 and 93.58 mg g−1, respectively. MB could almost be decomposed within 10 min depending on their concentration using AO-Fe-SWCNTs as catalyst under the assistance of H2O2. UV–Vis light irradiation further speeded up the above Fenton reaction and the degradation of MB and MO in solutions. It was revealed that the small sizes of iron oxides (several nanometers) and their good dispersion on SWCNTs are the main reason responsible for the good property of AO-Fe-SWCNTs. Furthermore, iron oxides-SWCNTs heterojunctions probably improve electron-hole separation during irradiation and promote the generation of hydroxyl radicals. The present study indicates that AO-Fe-SWCNTs with firm web structure are a promising material for adsorption and degradation of organic dyes.