Electrochemical removal of methylene blue using alginate-modified graphene adsorbents

This study aims to propose combined techniques for electrodegradation and adsorption using graphene oxide/alginate (GO/Alg) as an alternative method to enhance the removal of dyes from wastewater. Therefore, GO/Alg was newly synthesized and designed with an electrochemical cell. Methylene blue (MB), as a cationic dye commonly used by textile industries, was used as a model dye for evaluating the developed system. All the related experimental parameters were well optimized for the optimum efficiency of the proposed system. The composition of GO/Alg, concentration of CaCl₂, and pH solution have been investigated. The GO/Alg was characterized by XRD (X-Ray Diffraction), FTIR (Fourier Transform Infra Red), a SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope), and an SAA (Surface Area Analyzer). The characterizations presented that GO was well exfoliated in the alginate matrix. The optimum condition for removing MB dye was found to be pH 3.0, for 30 min at a voltage of 4.5 V with the first order rate constant (k) 7.45 × 10⁻² min⁻¹. In addition, the combined technique showed good removal efficiency in the simulated real textile sample with a percentage of ≥90%. This work proves that the electro-adsorption technique is more efficient than adsorption as a single technique.