Photochemical Synthesis Of Silver Nanonparticles Assisted By Penicillium And Its Use For Catalytic Reduction Of Organic Dye

Nanoparticle is an ultra fine particle with at least one dimension in the range of1-100nanometers. Synthesis of metal nanoparticles has increased extensively due to their unique physical, chemical and biological properties and made them attractive in a variety of applications such as catalysis, biosensors, drug carriers, antibacterials and a series of fields. The synthesis of nanoparticle is one of the most fundamental and important work in the field of nanoresearch. In this paper, silver nanoparticles (AgNPs) were rapidly synthesized by photochemical method assisted by Penicillium. The approach for synthesis of nanoparticles is a green and environmentally friendly synthesis method with the advantage of mild condition, clean, non-toxic and non-polluting.The main research contents include the following sections:1. The preparation of silver nanoparticles. AgNPs were synthesized by photochemical method assisted by the cell filtrate of Penicillium. The synthesized AgNPs were characterized by means of UV-Vis absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM).2. The influence of pH on the formation of AgNPs. Nine pH levels of cell filtrate, i.e.,5,6,7,8,9,10,11,12and13, were adjusted using NaOH or HNO3solution, then AgNPs were synthesized by photochemical method. The synthesized AgNPs were characterized by means of UV-Vis absorption spectroscopy, XRD, TEM, selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS) with zeta potential.3. Evaluation the catalytic activity of the synthesized AgNPs. The AgNPs prepared at pH8were used as catalyst for the reduction of methylene blue (MB) and congo red (CR) in the presence of NaBH4solution at room temperature. And UV-Vis absorption spectra were recorded to monitor changes in the reaction mixture to evaluate the catalytic properties of AgNPs.The results showed that:1. AgNPs can be rapidly synthesized by using AgN03contacted with cell filtrate of Penicillium under simulated solar irradiation. The results showed that the light played an important role in nanoparticle synthesis.2. pH is an important parameter having effects on the different aspects of nanoparticles formation, which have an impact on the rate of synthesis, size, dispersion and stability of AgNPs. At pH8, the nanoparticles were spherical in shape with average particle size of6nm and dispersed in solution but with certain aggregation. At pH12, we successfully synthesized high stable AgNPs with average size of4nm, uniform particle size and well-dispersed in solution without obvious aggregation. Experiment results showed that the reaction could easily proceed under alkaline conditions.3. The AgNPs exhibited high catalytic property towards the reduction of MB and CR in the presence of NaBH4soluion.