Green synthesis, characterization and photocatalytic application of silver nanoparticles synthesized by various plant extracts

Abstract Recently, the discharge of effluent containing dyes and other chemicals into river, lakes, and land has become a serious problem which increases the pollution level drastically. The dyes in the effluent are very difficult to be removed by conventional water treatment methods. Thus, there is a great need for more advanced methods that are cost-effective and more efficient. In this study, silver nano particles (AgNps) were synthesized by green method using extracts of onion (O), tomato (T), acacia catechu (C)alone, and mixed COT extracts. The reduction and formation of AgNps and its ions have been characterized by using several techniques, Ultra visible spectroscopy (UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM)-energy dispersive X-ray spectrometer (EDX), Fourier transmission infrared spectroscopy (FTIR), and dynamic light scattering (DLS). These techniques revealed that the particle sizes of synthesized AgNps in all the extracts were ranged in between 5 – 100 nm with a crystalline nature. The synthesized AgNps were used as catalysts for the degradation of three different types of dyes, methyl orange (MO), methyl red (MR), and congo red (CR) in the liquid state. The excellent catalytic application of all the synthesized AgNps on the degradation of the studied dyes was confirmed via UV-visible results by studying the reduction in the absorbance maxima value within a very short interval of time. COT synthesized products were found to achieve the best performance for all dyes degradation among all products.