In terms of biocompatibility, environmental friendliness, scalability, and cost-effectiveness, green nanoparticle (NP) synthesis is a modern area of nanotechnology that performs better than physical and chemical methods. The utilization of endophytic Penicillium oxalicum for the biogenesis of silica nanoparticles is the goal of the current work. The structural and optical properties of the fungal produced silica nanoparticles were investigated utilizing transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), x ray diffraction (XRD) and dynamic light scattering (DLS). All of the investigated parameters and their interactions were found to have a significant effect on the crystallite size, according to the results. The average diameter size of the biosynthesized SiO2-NPs was ranged between 20 -50 nm. The size of the biosynthesized SiO2-NPs was 28.7 nm, and their crystalline nature was confirmed by XRD, according to characterization results. A surface plasmon resonance spectrum of silica nanoparticles was obtained at 280 nm. Under UV light, Ribazol black b and Crystal violet dyes were photocatalytically degraded utilizing biosynthesized SiO2 nanoparticles. The highest decolorization percentage of Crystal violet and Ribazol black b was 94.1% ± 1.2% and 85.1% ± 0.93%, respectively after 90 and 120 min, for both crystal violet and Ribazol black b of incubation at 50.0 mg mL─1 of SiO2 nanoparticles. Furthermore, SiO2-NPs were successfully used more than once for biodegradation and that was regarded as its efficacy. Silica nanoparticles were used to remove Co, Pb, Cd, and Zn with percentages of 99.9% ± 1.2%, 99.9% ± 1.3%, 99.9% ± 1.3%, and 99.4% ± 1.4%, respectively. The phytotoxicity test was investigated by using Zea mays L seed which the root length increases to (28 ± 0.35) and (21 ± 0.51) cm, respectively when subjected tothe treated CV and Ribazole black b effluent... In conclusion, endophytic Penicillium oxalicum was used to successfully biosynthesize SiO2-NPs, which showed, phytotoxicity, heavy metal bioremediation, and photocatalytic activity against CV and Ribazol black b dye.
