Competitive Adsorption of Methylene Blue and Cu(II) onto Magnetic Graphene Oxide/Alginate Beads

Considering weak stability, difficult separation, poor mechanical property and thermal strength of polysaccharide materials, magnetic graphene oxide/alginate beads (mGO/CA) were synthesized for competitive adsorption of MB and Cu2+ in single and binary aqueous solution. The characteristics results of FTIR, XRD, and SEM indicated that the mGO/CA was successfully fabricated. The adsorption of MB and Cu2+ on mGO/CA was studied systematically in single and binary systems. For single system, the pH affected the adsorption of MB and Cu2+ on mGO/CA and the optimized pH value was observed at 5.0. In single and binary systems, the pseudo-second-order kinetic model and Langmuir isotherm model were found to describe the MB and Cu2+ adsorption well; the diffusion process with two stages for MB and Cu2+ can describe the adsorption process. The adsorption capacity of MB and Cu2+ in binary system was attenuated compared to that in single system. MB and Cu2+ can inhibit each other’s adsorption ability. Cu2+ had a better competitiveness than MB due to the difference in the electronic structure and the molecular size. In general, mGO/CA can be proved to be an multifunctional adsorbent to remove heavy ions and anion dyes from aqueous solution.