Comparative evaluation of cationic and anionic dye removal using graphene oxide fabricated by Hummers and Couette-Taylor flow methods

Graphene oxide (GO) has garnered significant attention from researchers owing to its exceptional physicochemical properties. GO is typically synthesized through chemical oxidation followed by exfoliation processes. In this study, we employed the Hummers method and the Couette-Taylor flow method to produce GO. The Couette-Taylor flow method offers the advantage of shorter oxidation reaction times and reduced wastewater compared to the Hummers method. We conducted surface analysis (including scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS), Zeta potential, multiple-point Brunauer Emmett Teller(BET), and atomic force microscope(AFM)) to assess and compare the surface characteristics of GO. Our analysis revealed that GO synthesized using the Couette-Taylor flow method (GO/Taylor) exhibited smaller lateral sizes. Additionally, we performed Particle Size Distribution Analysis (PSA) to verify the particle distribution of GO. The mean particle sizes of GO produced via the Hummers method and the Couette-Taylor flow method were determined to be 49.87 μm and 28.97 μm, respectively. These differences in surface properties and particle sizes influenced the adsorption capacity of GO for dyes. Considering the polarity, Cationic dye (BV1) and anionic dye (RR141) were selected for our adsorption experiments based on their polarity. Furthermore, we employed kinetic and isotherm adsorption modeling to analyze the adsorption mechanism in detail.