Effective demineralization of malachite green, and Janus green blue dyes with nickel oxide nanoparticles: a novel green chemistry method

Solution combustion method (SCM), with urea as a fuel, is a convenient method to synthesize nickel oxide (NiO) nanoparticles. NiO nanoparticles have been characterized using UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM) with EDX, transmission electron microscopy (TEM), and BET surface area determination. The average size of the NiO nanoparticles is 22 nm, and it has a band gap of 3.17 eV. It also showed a cubical assembly. Furthermore, the average size of NiO nanoparticles has been confirmed via TEM analysis, which is 25 nm. Malachite green (MG) and Janus green blue (JGB) dye degradation under solar irradiation could be prevented with synthetic NiO nanoparticles with the modification of catalytic concentration, pH, and the dye concentrations. The NiO nanoparticles demonstrated superior photocatalytic degradation against MG, and JGB as 97% and 96%. The catalyst concentration, pH, and dye concentration were varied with the aim to measure the degradation efficiency. A dye concentration of 1 × 10-4 mol/dm3 and a dye pH of 4 provided the most effective results.