EDTA functionalised cocoa pod carbon encapsulated SPIONs via green synthesis route to ameliorate textile dyes - Kinetics, isotherms, central composite design and artificial neural network

Abstract Even though adsorption by nanomaterial adsorbents epitomises an emergent technique to ameliorate the dye pollutants in the aqueous medium, the facile agglomeration and low recovery have circumscribed such potential applications. The present study exposes the furtherance in water treatment technology which embodies the advancement of the economic, photogenic, and eco-friendly nanohybrid composite. This study investigates the synthesis and characterisation of novel magnetic iron oxide nanoparticles loaded with cocoa pod carbon composite (Fe3O4/CC) for dye removal. The magnetic cocoa pod carbon composite was modified using EDTA through low cost biogenic green synthesis route and their application for adsorption of methylene blue and crystal violet. The characterisations of both Fe3O4/CC and EDTA- Fe3O4/CC were carried out using XRD, FTIR, FESEM, EDX, VSM, TGA and TEM. The adsorption studies of methylene blue and crystal violet were studied in batch mode experiments. The influence of operating parameters on dye adsorption efficacy was evaluated by performing the central composite design followed by modelling using artificial neural network. The experimental colour removal was found to match with the prediction value obtained by utilising response surface methodology with an artificial neural network (RSM-ANN) model, respectively. The maximum adsorption capacity of EDTA functionalised composite for methylene blue and crystal violet was 147.43 mg/g and 162.25 mg/g respectively. To understand dye mechanism involved in dye adsorption, isotherms and kinetic studies were carried out which proved that adsorption follows Freundlich isotherm and Pseudo-second order. The adsorbent demonstrated high regeneration, and recoverability studies showed that EDTA functionalised Fe3O4/CC is an efficient adsorbent for both cationic textile dyes. The efficient capturing of dye pollutant with the minimum usage of biocompatible adsorbent presents a simple and cost-effective technique for water treatment.