Synthesis of Silver Nanoparticles Using Azadirachta indica (Neem) Extract and Usage in Water Purification

Nanotechnology is a developing field while reducing the matter on atomic and molecular scale sized between 1 to 100 nanometre in one dimension. This technology recently attracted various branches of application due to the dissimilar behaviour of the bulk material when reduced to its nano-size. One such application is the use of the nano structured material as adsorbents or catalysts to remove the toxic and harmful substances from air water. In this paper, the green synthesis of Silver Nanoparticles using Azadirachta indica (Neem) extract at room temperature is discussed along with the application of anti bacterial properties in water treatment. An aqueous solution of silver nitrate (AgNO3) was treated with neem leaf extract and the formation of crystalline structure was confirmed using UV spectrometer and Xray diffraction analysis. The Scanning and Transmission Electron Microscope results confirmed that the morphology and size of the nanoparticles were strongly dependent on number of process parameters such as reactants concentration, reaction pH, mixing ratio of reactants and interaction time of the reactants etc. To develop a filtrate system for water purification, the synthesized nanoparticles were coated on Polyurethane foams (PU) by overnight exposure to the aqueous solution. Several rounds of washing and air drying resulted in stable PU foam with uniform coating. The morphology of the foam was not altered after coating. The common bacteria Escherichia coli of 105 colony-forming units (CFU) per mL were prepared to be used as input water. The coated PU filter was soaked in this water for about 10 minutes and the analysis of the output water had shown the reduction in bacterial population. As the drinking water contamination with E-Coli is predominant in third world countries and the low cost of Neem extract due to it abundant availability and also the green synthesis without any toxic chemical will find great application in water treatment.