A versatile hydrogel template for metal nano particle preparation and their use in catalysis

We report the synthesis of a novel bulk hydrogel based on acrylamidoglycolic acid (AAGA) and its use as a template in the preparation of different metal nanoparticles. Furthermore, we demonstrate the efficient utilization of p(AAGA) composite hydrogel as a reactor vessel in the reduction of an organic contaminant, 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The swelling characteristics of the hydrogel at different pH and different concentrations of salts (NaNO3, NaCl) were studied, and experimental molecular mass between crosslink (Me) values was calculated. Experimental parameters that affect the 4-NP reduction rate such as temperature, amount of catalysis, co-catalysis, concentrations of 4-NP and of NaBH4 were investigated. The kinetics of the reduction reaction under different reaction conditions was also evaluated to determine the activation parameters. Activation energy for the reduction of 4-NP was 33.783 kJ mol(-1) and p(AAGA)-Ag composites possessed 88% activity at the end of five repetitive uses. (C) 2011 Elsevier Ltd. All rights reserved.