Evaluation of the aqueous Fe (II) ion sorption capacity of functionalized microcrystalline cellulose

The absence of relevant functional groups, especially the oxygen-based groups, have been reported to strongly limit the metal binding capacity of native cellulose. Therefore, this study successfully introduced substantive oxygenous functional groups (C=O, -OH, C-O, etc.) onto microcrystalline cellulose via functionalization with 1,2,3,4-Butanetetracarboxylic acid. The synthesized adsorbent ('FM-cell') was further utilized for aqueous iron (II) ion uptake. The adsorbent's instrumental characterization (scanning electron microscopy, SEM; Energy dispersion X-ray, EDX; X-ray diffraction, XRD and Fourier-transform infrared spectroscopy, FTIR) result confirmed the presence of the oxygen-based functional groups and their relative structural crystallinity. Similarly, the effect of the process variable on the 'FM-cell' adsorption capacity was elucidated via batch mode. The Dubinin-Radushkevich and intraparticle diffusion models satisfactorily predicted the isotherm and kinetic data, respectively. The sorption mechanism postulated strong adsorbent-adsorbate electrostatic interaction occasioned by the large coordination number of Fe (II) ions. Thus, the surface oxygenous functional groups abundance significantly enhanced the metal binding capacity of 'FM-cell'.