Photocatalytic decomposition of methylene blue and methyl orange dyes using pistachio biochar/CoFe2O4/Mn-Fe-LDH composite as H2O2 activator

Photocatalysis has gained a lot more notice due to its simplicity, cost-effectiveness, and efficiency, especially for dye degradation. In this study, a novel composite (PBC/CoFe2O4/Mn-Fe-LDH) including pistachio biochar (PBC), CoFe2O4 magnetic nanoparticles, and Mn-Fe-layered doubled hydroxide (LDH) was produced using a co-precipitation method. The composite was utilized to remove methylene blue (MB) and methyl orange (MO) dyes from aqueous solutions by the photodegradation method. The Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analyses were used for characterization of the desired samples. The designed variables were pH (2-10), concentration of dye (10-30 mg.L−1), photocatalyst amount (0.2-1 g.L−1), H2O2 quantity (10-50 µL/100 mL), and time (10-50 min). The maximum degradation of MB and MO at optimal conditions (pH: 2 for MO and 10 for MB, dye concentration: 10 mg.L−1, catalyst mass: 1 g.L−1, time: 50 min, H2O2 value: 30 μL/100 mL) was obtained 99.10% and 99.89%, respectively. The scavenger effect investigation indicated that the species of OH• and O2•−, and h+ have the main function in the MB and MO degradation. The data were well explained by the pseudo-first-order kinetic model, and the constants for MB and MO dye elimination were established as 0.060 min−1 and 0.056 min−1, respectively. The PBC/CoFe2O4/Mn-Fe-LDH as a novel and promising composite could be useful for dye degradation in the photocatalytic reactor.