Ultrasound assisted mixed azo dye adsorption by chitosan-graphene oxide nanocomposite

Mixed azo dyes present in various effluents may often impair adsorption efficiency thereby questioning applicability of the same in a real-time scenario. In this study, simultaneous adsorption of acid yellow 36 (AY) and acid blue 74 (AB) from their aqueous solutions was carried out with graphene oxide nanoplatelets embedded in chitosan matrix (GO-Cs-Nc) with assistance of ultrasound exposure. Results obtained were subjected to analysis for process isotherms, kinetics and thermodynamics. This process was also optimized for best results using response surface methodology (RSM) and modelled with artificial neural network (ANN). The nanocomposite was characterised both before and after adsorption using FTIR, SEM, TEM and AFM. Under the experimental conditions prescribed by RSM, 0.50 g L-1 of adsorbent was responsible for 98.18% and 98.80% removal of AY and AB respectively when exposed to 6.48 min of ultrasonic irradiation. Hence, ultrasound assisted GO-Cs-Nc proved to be a cost effective and sustainable adsorbent effective in low dosage and significantly reduced time with possible application for treatment of real industrial effluents rich in mixed dyes. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.