Growth and Removal Behavior of Magnesium Oxide Microspheres towards Methyl Orange and Methylene Blue in Aqueous Solution

Abstract

The adsorption of dyes from the industrial influent has attracted great interest to overcome water pollution. In this work, we carefully investigated the growth process of hierarchical MgO microspheres and the difference in the corresponding removal behavior towards two dyes: anionic methyl orange and cationic methylene blue. The MgO microspheres were formed by the self-assembly of thin nanosheets following the reaction time and exhibited the maximum removal capacities are 940.14 mg g-1 for methyl orange and 354.00 mg g-1 for methylene blue. The anionic methyl orange and cationic methylene blue adsorption follow the pseudo-second-order kinetic model, Freundlich isothermal model. The difference in the removal behavior towards two dyes is strongly related to the surface charge of MgO and the charge of pollutants. This work will benefit design and improvement in the removal performance of novel porous adsorbents.