Graphene Oxide–Chitosan Composite Material for Treatment of a Model Dye Effluent

Abstract

Graphene 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 13 C 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 ( Q m ; mg g –1 ) with MB reveals twofold variation for Q m , 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.

Dye removal by biosorption using cross-linked chitosan-based hydrogels

“…Chitosan represents an alternative as ecofriendly complexing agent because of its low cost, its intrinsic characteristics, e.g., renewable, nontoxic and biodegradable resource, and hydrophilicity, and its chemical properties, e.g., polyelectrolyte at acidic pH, high reactivity, coagulation, flocculation and biosorption properties, resulting from the presence of reactive hydroxyl and mostly amine groups in the macromolecular chains (Roberts 1992;Sandford 1989;Skjåk-Braek et al 1989;de Alvarenga 2011;Teng 2016). These groups allow chemical modifications yielding different derivatives for specific domains of application (Bhatnagar and Sillanpää 2009;Sudha 2011;Azarova et al 2016;Arfin 2017;Ahmed and Ikram 2017;Sudha et al 2017;Wang and Zhuang 2017).…”

“…One of the most important properties of chitosan is its cationic nature. This aminopolysaccharide is the only natural cationic polymer in the nature (Roberts 1992;Kurita 1998Kurita , 2006Ujang et al 2011;Teng 2016). At low pH, usually less than about 6.3, chitosan's amine groups are protonated conferring polycationic behavior to polymer while at higher pH (above 6.3), chitosan's amine groups are deprotonated and reactive.…”

Effect of Graphene Oxide as a Reinforcement in a Bio-Epoxy Composite

“…A second minor weight loss observed for all materials ranged from 120 to 180 • C due to desorption of vapors from the hardening agent [62]. In aprevious study, it was reported that GO begins to decompose/deteriorate at a variety of elevated temperatures of 120 • C [63], 150 • C [51] and 200 • C [20], which leads to the loss of its surface-bound oxygen functional groups. The TGA for GO composites did not have a significant weight loss compared to the pure epoxy, possibly due to the small GO loadings.…”

Environmental Remediation Applications of Carbon Nanotubes and Graphene Oxide: Adsorption and Catalysis

“…And the adsorption followed a PSO kinetics and Freundlich-type multilayered model. Recently, Sabzevari et al [123] pointed out that current GO framework products were of limited applications in water treatment because of scalability as the result of repulsive hydration forces between GO layers. To this end, they tried to cross-link GO within chitosan to yield a composite (GO-LCTS) via the interaction between the amine groups of chitosan and the carboxyl groups of GO, resulting in enhanced surface area and structural stability.…”