Fabrication and characterization of recyclable, magnetic (CoFe2O4)x/Ag2S-ZnO composites for visible-light-induced photocatalytic degradation of methylene blue dye
Emmanuel Ichipi, António Benjamim Mapossa, Ana Cristina Figueiredo de Melo Costa, Evans M. N. Chirwa, Shepherd M. Tichapondwa
Abstract
Magnetic (CoFe2O4)x/Ag2S-ZnO composites (where x = 0.25, 0.5, 0.75 and 1 wt% CoFe2O4) were successfully synthesised and investigated in the removal of methylene blue (MB) from aqueous medium under visible-light irradiation. X-ray diffraction (XRD) analysis confirmed the crystallinity of the as-synthesised materials and established the average crystal size of these materials to be <8.5 nm. Vibrating sample magnetometer (VSM) analysis confirmed that all cobalt ferrite doped nanocomposites exhibited ferrimagnetic behavior with saturation magnetization values varying from 6.55 to 40.52 emu/g being recorded. Near complete degradation (99 %) was attained when 1 gL−1 of (CoFe2O4)0.5/Ag2S-ZnO composite was added to a 10 ppm solution of methylene blue (MB) at neutral pH for 4 h of visible light irradiation. The catalyst showed good stability, removing 93.1 % of MB dye after five reuse cycles. The composite catalyst reported in this study is therefore a promising material for large-scale water and wastewater treatment processes.