Microwave-assisted green synthesis of silver nanoparticles by carboxymethyl cellulose sodium and silver nitrate

In the present work, silver nanoparticles are prepared by a simple green method. Carboxymethyl cellulose sodium (CMS) is employed to work as both a reducing and a stabilizing reagent in the reaction. Although the hydrolysis of CMS in aqueous solution without the help of catalyst is nearly impossible using conventional heating method, our experimental results show that it can be achieved when the reactive system is radiated by microwave. Consequently, silver ion can be reduced by the hydrolyzate of CMS to form silver nanoparticles. Further studies reveal that CMS with a high concentration will lead to high reactive speed and big particles, however, the inborn silver nanoparticles will be smaller when the CMS concentration is higher than 0.04% for 0.1 mM AgNO3. Experimental results have also shown that the concentration of CMS has very small effect on the size distribution, whereas the impact of AgNO3 concentration is obvious. AgNO3 with high concentration will result in big particle and broad size distribution in this reaction. The silver nanoparticles prepared in this way are uniform and stable, which can be stored at room temperature for 2 months without any visible change.