ao8b01871_si_001.pdf (370.36 kB)
Graphene Oxide–Chitosan Composite Material for Treatment of a Model Dye Effluent
journal contribution
posted on 2018-10-11, 11:34 authored by Mina Sabzevari, Duncan E. Cree, Lee D. WilsonGraphene
oxide (GO) was cross-linked with chitosan to yield a composite
(GO-LCTS) with variable morphology, enhanced surface area, and notably
high methylene blue (MB) adsorption capacity. The materials were structurally
characterized using thermogravimetric analysis and spectroscopic methods
(X-ray diffraction, Fourier transform infrared spectroscopy, Raman
spectroscopy, and 13C solid-state NMR) to support that
cross-linking occurs between the amine groups of chitosan and the
−COOH groups of GO. Equilibrium swelling studies provide support
for the enhanced structural stability of GO-cross-linked materials
over the synthetic precursors. Scanning electron microscopy studies
reveal the enhanced surface area and variable morphology of the cross-linked
GO materials, along with equilibrium and kinetic uptake results with
MB dye in aqueous media, revealing greater uptake of GO-LCTS composites
over pristine GO. The monolayer uptake capacity (Qm; mg g–1) with MB reveals twofold variation
for Qm, where GO-LCTS (402.6 mg g–1) > GO (286.9 mg g–1). The kinetic
uptake profiles of MB follow a pseudo-second-order trend, where the
GO composite shows more rapid uptake over GO. This study reveals that
the sorption properties of GO are markedly improved upon formation
of a GO–chitosan composite. The facile cross-linking strategy
of GO reveals that its physicochemical properties are tunable and
versatile for a wider field of application for contaminant removal,
especially over multiple adsorption–desorption cycles when
compared against pristine GO in its highly dispersed nanoparticle
form.