Fast 4-nitrophenol reduction using gelatin hydrogel containing silver nanoparticles

Abstract

The current study reports the synthesis of gelatin hydrogel containing silver nanoparticles (AgNPs) and its role as a catalyst. A porous gelatin hydrogel, with pore size of 15-100 nm, was prepared by cooling its hot solution to room temperature with glutaraldehyde as crosslinker. The gelatin hydrogel was immersed in 1 mM silver nitrate solution for 24 h through ex-situ impregnation. The impregnation of AgNPs was confirmed through field-emission scanning electron microscopy (FE-SEM) which showed uniform dispersion of nanoparticles on the hydrogel surface and partial impregnation into the matrix. Thermogravimetric analysis (TGA) showed the impregnation of 9 wt% of AgNPs in the hydrogel composite which also contributed to its improved thermal properties. X-ray diffraction (XRD) analysis confirmed the amorphous nature of gelatin and addition of AgNPs. The AgNPs/gelatin hydrogel effectively reduced 4-nitrophenol by sodium tetrahydroborate at a reaction rate constant of 0.498 min-1. The prepared AgNPs/gelatin hydrogel could be used as a catalyst for other similar type of reactions.