Síntesis de nanopartículas de plata depositadas in situ en disilicato de litio para su uso como catalizador

Abstract

Water plays an important role in industry as a raw material in its processes and as a means of removing its waste, causing a negative variation in the characteristics of the water resource. Among the industries present in Colombia, the textile sector generates a series of environmental problems due to the load of dyes used in the dyeing area. P-nitrophenol is one of the main dyes responsible for harmful effects in water because it produces eutrophication, formation of recalcitrant compounds and the reduction of dissolved oxygen (DO). In this research work, three types of silver nanoparticles (AgNPs) deposited in situ in lithium disilicate were synthesized to evaluate their catalytic activity in reducing p-nitrophenol (4NP) to p-aminophenol (AP) with sodium borohydride. At the end of the reduction, a monitoring was performed using the technique of infrared spectroscopy to the catalyzed solution, observing characteristic peaks that indicated the presence of 4AP such as: a peak of asymmetric tension of the N-H bond at 3400 cm-1 and in the region of 1800 cm-1 the characteristic peaks of aromatic para-substituted, indicating the presence of 4AP. In addition, it was observed that the AgNPs reduce the 4NP from 80 to 100% in a time between 8 and 39 minutes, depending on the type of AgNPs synthesized. The AgNPs were characterized with dynamic light scattering (DLS), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS), confirming that the AgNPs have a size ranging from 15.6 to 30 nm; they also remain adsorbed on the surface of lithium disilicate. The results show that the proposed systems are an alternative for pre-treatment of recalcitrant water compounds