Environmental synthesis of silver nanoparticles using hydroxypropyl starch and their characterization

Silver nanoparticles (AgNPs) were synthesized in an alkaline aqueous solution of silver nitrate (AgNO3)/hydroxypropyl starch (HPS) using chemical reduction method. HPS is water soluble/biocompatible starch derivative which play a dual rule as reducing agent for silver ions and as stabilizing agent too for the formed AgNPs. The influences of the reaction parameters, such as the concentrations of HPS and AgNO3. pH, temperature, and duration of the reaction medium on the size and agglomeration of the formed AgNPs were studied. The formation of AgNPs has been confirmed with ultraviolet-visible spectra and transmission electron microscopy (TEM) images. The diameter range of well stabilized AgNPs solution with a concentration of 500 ppm of a diameter of 6-8 nm was obtained. The obtained AgNPs remain without aggregation for more than six months. The advantage of this methodology is that it is possible to prepare AgNPs without any organic solvents or other reducing agents. (C) 2011 Elsevier Ltd. All rights reserved.