Eco-friendly synthesis of biochar supported with zinc oxide as a heterogeneous catalyst for photocatalytic decontamination of Rhodamine B under sunlight illumination

In the current study, biochar, as a porous and low-cost carbon derived from Pontederia crassipes L. leaves, was loaded with zinc oxide for the photocatalytic discoloration of Rhodamine B dye in aqueous suspension under solar light irradiation. For the comparison, the unmodified zinc oxide and biochar samples were prepared. The synthesizing materials were investigated by X-ray powder diffraction, UV-DRS spectrophotometer, field emission scanning electron microscopy, Fourier transform infrared spectrometer, and Raman spectroscopy. The synthe-sized ZnO/Biochar hybrid has improved features, besides narrowing the band gap energy, and enhancing the surface area of the photocatalyst. The ZnO/biochar nanohybrid displayed an excellent photocatalytic degrada-tion efficiency (99. 67 %) of Rhodamine B in the presence of H2O2 with 120 min of solar light irradiation. The results of recyclability study of ZnO/Biochar in the photocatalysis process verified its physical and chemical stability after five repeated cycles, hence it retained of 82.24 % of initial activity. Furthermore, the photo -catalytic discoloration reaction was compatible with the pseudo-first-order kinetic model