This paper evaluates the adsorptive removal of sunset yellow (SY) from aqueous solutions using a new magnetic glycodendrimer (MGD). To synthesize the MGD, chitosan dendrons were cultivated on amine-functionalized magnetic graphene oxide. A number of analytical methods were employed to physicochemically characterize the synthesized MGD. Batch adsorption conditions were optimized using the Box–Behnken design. An optimized initial SY content of 633 mg/L, an optimized contact time of 33.37 min, and an optimized pH of 3.72 maximized the MGD adsorption capacity to 485 mg/g. The Langmuir isotherm was employed to describe adsorption equilibrium, while adsorption kinetics was studied via the Lagergren kinetics model. The SY adsorption onto the MGD was thermodynamically found to be spontaneous (ΔG° < 0) and exothermic (ΔH° = – 19.120 kJ/mol), leading to a decreased disorder (ΔS° = – 54.420 kJ/mol) in the solid–liquid interface. The MGD showed reusability and unique magnetic characteristics. It was concluded that the MGD could be a potential alternative for the adsorptive and magnetic removal of SY from an aqueous solution.

Chitosan dendron-cultivated magnetic graphene oxide as novel glycodendrimer for adsorptive removal of sunset yellow from aqueous solutions
    Abstract
    1 Introduction
    2 Experimental setup
        2.1 Materials
        2.2 GO synthesis
        2.3 MGO synthesis
        2.4 MGO-NH2 synthesis
        2.5 MGD synthesis
        2.6 Characterization
        2.7 Adsorption experiments
    3 Results and discussion
        3.1 MGD synthesis and characterization
        3.2 Optimization of SY removal parameters via RSM
        3.3 MGD regeneration and effects of co-existing ions on SY removal
        3.4 Adsorption isotherms
        3.5 Adsorption kinetics
        3.6 Adsorption thermodynamics
    4 Conclusion
    Acknowledgements 
    References

• Seyed Ali Razavikia(Department of Chemical Engineering, Yasuj Branch, Islamic Azad University, Yasuj, Iran)
• Mehdi Faramarzi(Department of Chemical Engineering, Yasuj Branch, Islamic Azad University, Yasuj, Iran, Department of Chemical Engineering, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran)
• Seyed Aboutaleb Mousavi Parsa(Department of Chemical Engineering, Yasuj Branch, Islamic Azad University, Yasuj, Iran)
• Hajir Karimi(Department of Chemical Engineering, Yasuj Branch, Islamic Azad University, Yasuj, Iran, Department of Chemical Engineering, Yasouj University, Yasouj, Iran)