Catalytic degradation of malachite green using a crosslinked colloidal polymeric system loaded with silver nanoparticles
Zahoor H. Farooqi, Hamadia Sultana, Robina Begum, Muhammad Usman, Muhammad Ajmal, Jan Nisar, Ahmad Irfan, Muhammad Azam
Abstract
Aim of this work is to investigate the catalytic efficiency of silver nanoparticles loaded poly(N-isopropylacrylamide-co-acrylic acid)[Ag-P(NAA)] microgel system towards degradation of an organic dye (malachite green (MG)) in aqueous medium. Ag-P(NAA) system was synthesised by free-radical precipitation polymerisation followed by in-situ reduction of silver nitrate in the presence of reducing agent. Fourier transform infrared, UV-Visible Spectroscopy and transmission electron microscopy were employed for characterisation of synthesised catalytic system. Measurement of surface Plasmonic property of the silver nanoparticles was used to study the stability of the hybrid system as a function of time of storage and pH of the medium. Catalytic potential of Ag-P(NAA) towards reductive degradation of MG in aqueous medium was investigated. The experiments were performed at various concentrations of reducing agent, dye and catalyst for the evaluation of a kinetic parameter called apparent rate constant (kapp) using pseudo first-order kinetic model. The results revealed that hybrid microgels can degrade dye completely in few minutes. Values of kapp under different reaction conditions suggested that the catalytic process takes place through Langmuir–Hinshelwood mechanism. Ag-P(NAA) system is highly useful for the treatment of industrial waste water containing organic dyes.