Synthesis of zinc oxide nanoparticles (ZnO) by polyol method for concentration reduction of malachite green and rhodamine B dyes via photocatalytic

Zinc oxide nanoparticles (ZnO-P) were synthesized using the polyol method as a photocatalytic agent with a Zn2+ concentration of 0.5 mol/L, a base-to-Zn2+ ratio of 1, and an H2O-to-Zn2+ ratio of 5 (ZnOP-A) and 20 (ZnOP-B) for the reduction of malachite green and rhodamine B dye concentrations. XRD, FESEM, UV-DRS, and FT-IR were used to characterize ZnO-P. The results of the characterization revealed that the ZnO-P produced by the polyol method had a hexagonal crystal structure, a particle size of less than 100 nm, and a band gap energy (Eg) of approximately 3,2 eV. Depending on the hydrolysis ratio, the obtained particles have distinct morphologies. The particles synthesized with a hydrolysis ratio = 5 (ZnOP-A) were spherical and slightly elongated, whereas those synthesized with a hydrolysis ratio = 20 (ZnOP-B) were conical. Under UV-LED irradiation, the photocatalytic activity of zinc oxide nanoparticles to reduce the concentration of malachite green and rhodamine B dyes at concentrations of 20, 30, and 40 mg L-1 was evaluated. It was discovered that particle size and morphology affect the particles' ability to reduce the dye concentration. Within 12 minutes of irradiation, zinc oxide nanoparticles (ZnOP-A) reduced the concentration of rhodamine b dye by 98,454%, while malachite green dye concentration was reduced by 99,030% within 120 minutes of irradiation.