Preparation and characterization of cross-linked chitosan/palladium nanocomposites for catalytic and antibacterial activity

Simple chemical reduction method has been used to synthesize the chitosan supported palladium nanoparticles. The prepared samples were analyzed using various characterizations. 4-Nitrophenol (4-NP) is a toxic water pollutant The catalytic hydrogenation of recalcitrant pollutant by sodium borohydride is the prime model reaction that can be easily analyzed using the spectroscopic techniques. The catalytic performance of the synthesized chitosan/palladium (CS/Pd) nanocomposites with different weight percentages of palladium, for 4-nitrophenol reduction was also investigated. On increasing the palladium concentration, the catalytic activity towards conversion of highly toxic 4-nitrophenol to eco-friendly 4-aminophenol and antibacterial activity against human pathogens is increased due to non-agglomerative nature of mono-dispersed palladium nanoparticles. The kinetic rate constant during the catalytic performance was found to be 1.95 x 10(-3), 2.41 x 10(-3) and 4.01 x 10(-3) s(-1) for CS/Pd-5%, CS/Pd-10% and CS/Pd-15% respectively. The nanocomposites exhibited superior antibacterial efficacy against both Gram negative and Gram positive bacteria. The in vitro minimum inhibitory concentration of the compound against human pathogens was determined. Further, the nanocomposite is screened for hemolytic activity and it proved that the chitosan stabilized Pd NPs are non-toxic on RBCs cells up to the concentration of 25 mu g/ml among tested concentration. (C) 2018 Elsevier B.V. All rights reserved.