Investigation of Eosin B Removal from Aqueous Solution Employing Combined Graphene Oxide Adsorption and Zinc Oxide Coagulation Processes

Abstract

In this study, graphene oxide was synthesized and investigated as an adsorbent for eosin B elimination. The features and structure of graphene oxide were determined by employing scanning electron microscopy, transmission electron microscopy, Raman spectrometry, and X-ray diffractometry. Graphene oxide can remove dyes in water solutions, but it is confronted by separation challenges. Therefore, zinc oxide was used as a coagulant for separation of the dye solution from graphene oxide. Adsorption properties such as contact time, dye concentration, dosage of adsorbent, zinc oxide content, pH effect, and temperature were regularly investigated extensively. Concentrations of dyes in the supernatant suspension were evaluated employing a visible spectrophotometric method at the maximum wavelength (λmax) of 514 nm. The eosin B dye showed maximum sorption capacity of 68.027 mg/g at pH 4 and T=298 K. Isotherm models such as Freundlich and Langmuir isotherms were used to determine the better suitable isotherm model. It was discovered that this dye adsorption capacity on adsorbent particles was monolayer and had a good agreement with the Langmuir isotherm. Pseudo-first-order and pseudo-second-order kinetic models were investigated to determine adsorption kinetics. The pseudo-second-order for sorption of this dye on adsorbents was followed by kinetic data analysis. This research shows that this sorbent and coagulant are efficacious and applicable for the removal of eosin B from wastewaters.