CoFe2O4 nanoparticles decorated onto graphene oxide and graphitic carbon nitride layers as a separable catalyst for ultrasound-assisted photocatalytic degradation of Bisphenol-A

Abstract

The advanced oxidation process (AOP) through ultrasound-assisted photocatalytic degradation has attracted much attention in removing emerging contaminants. Herein, CoFe₂O₄-GO and CoFe₂O₄-g-C₃N₄ nanocomposites were synthesized using the ultrasound-assisted co-precipitation method. TEM, XRD, XPS, EDS, SEM, and FT-IR techniques characterized the structural, morphological, and chemical properties of the synthesized nanocomposites. The analyses showed that CoFe₂O₄ structure was nano-sized and distributed more homogeneously in graphene oxide (GO) layers with oxygenated functional groups than graphitic carbon nitride (g-C₃N₄). While the efficiency of composite catalysts, as photocatalysts, for degradation of bisphenol-A (BPA) was low in the visible region in the presence of persulfate, their catalytic efficacy was higher with sonolytic activation. The addition of persulfate as an oxidant remarkably enhanced the target pollutant degradation and TOC removal of BPA solution. Both composite catalysts showed 100 % BPA removal with the synergistic effect of visible region photocatalytic oxidation and sonocatalytic oxidation in the presence of persulfate at pH 6.8. In ultrasound-assisted photocatalytic oxidation of BPA, the highest mineralization efficiencies were obtained at 2 h treatment time, pH 6.8, 16 mM PS, catalyst dosages of 0.1 g/L CoFe₂O₄-GO, and 0.4 g/L CoFe₂O₄-g-C₃N₄ as 62 % and 55 %, respectively. An effective catalyst was obtained by reducing e^-/h⁺ recombination and charge transfer resistance by decorating the GO layers with CoFe₂O₄.

Keywords: Bisphenol-A; Cobalt ferrite; Graphene oxide; Graphitic carbon nitride; Photocatalyst; Sonocatalyst.