Textile dye removal from aqueous solutions using cheap MgO nanomaterials: Adsorption kinetics, isotherm studies and thermodynamics

Abstract

In the present study, three MgO nanomaterials (MgOS, MgON and MgOU) were synthesized by sol–gel and two different precipitation methods, respectively, and used for the sorption of Remazol Red RB-133 from aqueous solution. The effect of parameters like contact time, initial dye concentration and temperature on the adsorption capacity was studied. The adsorption isotherm studies were carried out using Langmuir, Freundlich and Temkin models. Langmuir was the most suitable model to describe the adsorption isotherm. Pseudo- first -order model fitted well with good agreement with the experimental values of qe (equilibrium adsorption capacity). The complete removal efficiency of the dye on MgOS, MgON and MgOU adsorbents was attained when the contacting time was continued to 11, 40 and 60min, respectively. Hence, the MgOS adsorbent was found to possess the highest removal efficiency of the dye from aqueous solutions. In addition, the thermodynamic parameters, ΔH°, ΔS°, ΔG°, and Ea were also calculated for Remazol Red RB-133 adsorption onto MgOS adsorbent. In order to reveal the adsorptive characteristic of MgO nanomaterials, XRD, HR-TEM, FT-IR and N2 adsorption/desorption isotherms were carried out. The results showed that MgOS nanomaterial had potentially lowering capital and operational costs for practical applications.