Superparamagnetic MnFe2O4 dispersed over graphitic carbon sand composite and bentonite as magnetically recoverable photocatalyst for antibiotic mineralization

Herein, we report synthesis of graphitic carbon sand composite (GSC) and bentonite (BT) supported superparamagnetic MnFe2O4 nanoparticles to obtain MnFe2O4/GSC and MnFe2O4/BT nanocomposites. Graphitic carbon sand composite (GSC) was prepared by graphitization of sugar over river sand. The particle size of MnFe2O4/GSC and MnFe2O4/BT was found to be 50 and 60 nm respectively. BET adsorption experiments confirmed mesoporous nature of prepared photocatalysts. Magnetic studies revealed superparamagnetic behavior of MnFe2O4/GSC and MnFe2O4/BT. The band gaps of MnFe2O4/GSC and MnFe2O4/BT were 2.38 and 2.42 eV respectively. Both MnFe2O4/GSC and MnFe2O4/BT exhibited significant photocatalytic activity for the mineralization of ampicillin (AMP) and oxytetracycline (OTC) antibiotics under solar light. Simultaneous adsorption and degradation process (A + P) resulted in higher photodegradation of OTC and AMP. The applicability of power law model indicated intricacies of mineralization process. MnFe2O4/GSC and MnFe2O4/BT displayed significant recycle efficiency and easier recovery of photocatalyst for 10 consecutive catalytic cycles.