Optimizing the synthesis conditions of silver nanoparticles using corn starch and their catalytic reduction of 4-nitrophenol
Hosam I Salaheldin
Abstract
In this study, silver nanoparticles (SNPs) were synthesised in an aqueous solution of corn starch. To fabricate the SNPs, reaction conditions, such as varying silver nitrate (AgNO3) concentration, time, temperature and solution pH of the reaction, were optimized. Since, the optimum reaction conditions were found 1 mmo l−1, 15 min and 90 °C, respectively. Then, to study the role of pH on SNP synthesis, varying pH values of the solution (3, 5, 7, 9 and 11) were investigated. Subsequently, the obtained silver/starch nanocomposites were characterised using different techniques. The x-ray diffraction (XRD) results revealed that the particles were face-centred cubic (FCC), and had an average particle size of 7.5 nm. This was confirmed by high-resolution transmission electron microscopy (HR-TEM) images. Moreover, the synthesised SNPs, at different pH values, were used as nanocatalyst for the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. Under optimum reaction conditions, the higher catalytic activity was obtained with SNPs synthesised at pH 11 compared to lower pH of 7 or 9. Therefore, the rapid, reproducible, cost-effective silver/starch nanocomposite can be widely used for various applications such as drug manufacturing (e.g. analgesics and antipyretics) and the removal of pollutants from wastewater
