Enhanced sono-assisted adsorptive uptake of malachite green dye onto magnesium ferrite nanoparticles: Kinetic, isotherm and cost analysis

Abstract

In this study, the performance of magnesium ferrite nanoparticles (MgF-NPs) as adsorbent was assessed for removal of toxic malachite green (MG) dye from aqueous solution under ultrasonic irradiation. The MgF-NPs exhibited specific surface area of 70.266 m2/g and pore volume of 0.311 cc/g with an average pore diameter of 7.354 nm. Optimum solution pH was found to be 8.0 for sono-assisted MG dye adsorption, which is favourable for large scale field application of the proposed method. The adsorption reaction aided by ultrasonication could yield more than 90% MG dye removal within 15 min of reaction due to enhancement of mass transfer. However, instead of ultrasonication when overhead stirring and shaking was used as mixing methods then the MG dye removal efficacy was dropped to 70% and 65%, respectively. The adsorption kinetic strictly followed the pseudo-second-order model and equilibrium isotherm analysis followed the Langmuir isotherm model with maximum monolayer adsorption capacity of 487.60 mg/g. The presence of chloride ion hindered the MG dye removal efficiency from 91% to 67%, whereas the presence of nitrate, sulfate and phosphate ions in the dye solution could not affect the dye removal efficacy significantly. The cost analysis for synthesis of MgF-NPs revealed that the cost involvement of 50.88 USD/Kg of adsorbent which may be considered as economical for large scale industrial application.