Rare earth-incorporated cobalt ferrite anchored on reduced graphene oxide nanocomposites with enhanced peroxydisulfate photocatalytic degradation of bisphenol A in aqueous solution

In recent decades, emerging water contaminants have raised significant global concern due to their impact on water quality, driving the need for more effective treatment strategies. In this work, magnetically separable samarium-incorporated cobalt ferrite supported on reduced graphene oxide (SmCoFe₂O₄/rGO) nanocomposites were prepared using a dual co-precipitation–hydrothermal approach for the photocatalytic degradation of bisphenol A (BPA). The synthesized samples were characterized using, FTIR, XRD, SEM, TEM, UV-DRS and BET adsorption–desorption measurements. The photocatalytic activity of SmCoFe ₂ O ₄ /rGO was increased under visible-light irradiation and in the presence of peroxydisulfate (PDS), with a maximum BPA removal efficiency of 99.4% within 120 min under optimal conditions ([BPA] = 20 mg/L, [SmCoFe ₂ O ₄ /rGO] = 25 mg, [PDS] = 1.5 mM, pH = 7.0). The interaction between rGO and Sm nanoparticles exhibited a synergistic effect and reduced electron–hole recombination rate, thereby facilitating charge transport, while CoFe ₂ O ₄ enabled recyclability due to its magnetic properties. Radical scavenger experiments were used to identify the formation of free radicals (SO ₄ ^•− and ^• OH) as the main reactive oxygen species (ROS) during the PDS-assisted photodegradation processes. Furthermore, the SmCoFe ₂ O ₄ /rGO exhibited high stability after five consecutive cycles and maintained catalytic activity. Finally, SmCoFe ₂ O ₄ /rGO photocatalyst demonstrated promising potential for the purification of water/wastewater containing BPA.