Investigation of the Adsorption Efficiency of Methylene Blue Dye in Water Treatment Using Graphene Oxide-Based Adsorbents

Abstract

Water pollution, particularly the release of industrial dyes into aquatic environments, has become a major environmental problem. Effective and economical treatment methods are needed to reduce this pollution. This study investigates the removal of methylene blue (MB) dye from aqueous solutions by adsorption using graphene oxide (GO). The study consists of three stages. In the first stage, the adsorption performance of GO synthesized by Staudenmaier, Staudenmaier–Hummers, and Hummers methods was compared. 0.1 g of GO was tested with a 300 ppm MB solution at 25 °C and a contact time of 24 hours. GO obtained by the Hummers method exhibited the highest performance with a maximum adsorption capacity of 570 mg/g and a removal efficiency of 95%. In the second stage, the effect of base types (NaOH, NH₄OH, and KOH) on adsorption efficiency was investigated. The best results were obtained using NaOH, with an adsorption capacity of 588 mg/g and a removal efficiency of 98%. In the third stage, the effect of pH was investigated, and the highest efficiency was obtained at pH 9 (466 mg/g capacity, 93.2% removal efficiency). GO samples were characterized by FTIR, zeta potential, and particle size measurements. It was determined that GO obtained by the Hummers method exhibited superior performance due to its high oxidation degree and active adsorption sites. In conclusion, the usability of GO as an effective adsorbent in removing cationic dyes, such as methylene blue, from wastewater was demonstrated. This study shows that graphene oxide has significant potential for environmental water treatment applications.