Functionalization of Graphite Oxide with Magnetic Chitosan for the Preparation of a Nanocomposite Dye Adsorbent

Abstract

In the current study, the functionalization of graphite oxide (GO) with magnetic chitosan (Chm) was investigated to prepare a nanocomposite material (GO-Chm) for the adsorption of a reactive dye (Reactive Black 5). The synthesis mechanism was investigated by various techniques (SEM/EDAX, FTIR spectroscopy, XRD, XPS, DTA, DTG, VSM). Characterization results indicated that a significant fraction of the amines of the chitosan (i) were inserted between the GO layers and (ii) reacted with carboxyl and epoxy groups of GO, leading to its reduction and hence the destruction of the layered structure. The concentrations of iron were found to be ∼25% for Chm and ∼12% for GO-Chm. A VSM plot presents the value of 9 emu/g for the saturation magnetization of GO-Chm. The adsorption behavior of the prepared composite was elucidated with a series of experiments. The tests of the effects of pH revealed that the adsorption mechanism dominated (between dye molecules and the GO-Chm matrix) and showed that acidic conditions were the optimum for the adsorption process (pH 3). Kinetic experiments presented the relatively "fast" adsorption phenomenon using pseudo-first-order, pseudo-second-order, and modified pseudo-second-order equations. The equilibrium data were fitted to the Langmuir, Freundlich, and Langmuir-Freundlich (L-F) models, calculating the maximum adsorption capacities at 25, 45, and 65 °C (391, 401, and 425 mg/g, respectively). Thermodynamic analysis was also performed to calculate the changes in free energy (ΔG(0)), enthalpy (ΔH(0)), and entropy (ΔS(0)).

Removal of acridine orange from water by graphene oxide

“…The strong band at 1045 cm -1 is due to the C-O bond, and the 998 cm -1 band is attributed to the stretching vibrations of C-H groups. FTIR spectrum reported in this study is in accord with previous data graphite oxide [18,19] and for grapheme oxide [22][23][24].…”

“…The adsorption experiments performed demonstrated the high capacity of GO as an adsorbent of AO [19,28]. UV-visible spectra performed in solutions of acridine orange showed the characteristic absorption peaks at wavelengths among 440 to 510 nm.…”

“…Recently, the application of nanomaterials in water management has attracted significant attentions due to the advantages of large surface areas and more active functionalized sites [24]. Several studies have been done to test carbon materials such as activated carbon [16], carbon nanotubes [17], graphite oxide [18][19][20], graphene and graphene oxide [21][22][23][24]. Graphene oxide (GO) attracts highest interest as it is a precursor of graphene [30][31][32][33], the fascinating two dimensional carbon-based material possessing atomic thickness, which attracted considerable attention world over, since the report of Novoselov et al [25].…”

“…GO is an oxygen-rich carbonaceous material obtained through the oxidation of graphite with strong oxidants [26]. It consists of randomly distributed regions of unoxidised (aromatic) graphene and regions of aliphatic six-membered rings, rich in oxygen-containing functional groups, including epoxies, hydroxyls and carboxylic groups [28][29][30], reported to be good adsorbent for water contaminated [18][19][20][21][22][23][24]. However, few investigations have been reported about adsorption of AO on graphene oxide.…”

A review: synthesis and applications of graphene/chitosan nanocomposites

“…The GO/f-CS/polyamide (PA) composite membranes showed superior performance compared to the unmodified PA membrane in terms of hydrophilicity, surface smoothness, water flux, and antifouling. Travlou et al [53] researched magnetic GO-CS, and thermomechanical analysis suggested that this material has a high adsorption capacity for sewage.…”