On the kinetics of block copolymer mediated palladium quantum dot synthesis: Application in reduction of Cr(VI) to Cr(III)

摘要

In this work we have designed a simple, eco-friendly, one-pot method for the synthesis of palladium nanopartides of quantum dot dimension (PdQDs) using a non-toxic, biocompatible block co polymer which functions as a reducing and stabilizing agent during the synthesis. The entire synthesis is free from any especial experimental set up and reaction conditions. These QDs were characterized by several well know characterization techniques such as UV-vis spectroscopy (UV-vis), transmission electron microscopy (TEM), Fourier transform infra-red spectroscopy (FTIR), dynamic light scattering (01,S), and potential measurements. The transformation of a yellow solution into dark brown solution was indicative of the formation of the PdQDs. The kinetics of this reaction was monitored using a time scan absorption measurement which reveals a sigmoidal curve, a signature of noble metal nanoparticles. The rate of nucleation and growth were calculated using Finke and Watzky model. The synthesized colloidal PdQDs were employed for the reduction of environmentally toxic Cr(VI) to safer Cr(III). The reaction was catalyzed by the PdQDs in presence of acetic acid and was dependent on the concentration of both. The order and rate constant of the reduction reaction was calculated. A comparatively faster and complete reduction of Cr(VI) to Cr(III) using this catalysis was achieved at room temperature in presence gamma irradiation, thus making the method more effective in its approach for bulk remediation of Cr(VI). (C) 2017 Elsevier B.V. All rights reserved.