Hydrothermal synthesis of a graphene/magnetite/montmorillonite nanocomposite and its ultrasonically assisted methylene blue adsorption

Acid Red 66 Dye Removal from Aqueous Solution by Fe/C-based Composites: Adsorption, Kinetics and Thermodynamic Studies

“…Apparently, the anionic azo dye adsorption takes place primarily in the OH groups responsible for the negative charge of Fe from the accessible cubic Fe3O4 structure through the sulfate groups of the dye. This is in accordance with the findings from Mössbauer and XRD techniques and in line with the findings [16]. The saturation of the adsorption capacity of Fe3O4 particles may occur and thus, the dye adsorption capacity onto Fe sample is low, when the time of reaction passed.…”

“…The working adsorption isotherm models such as Langmuir and Freundlich equations were applied as described in the literature [16]. The kinetic adsorption was evaluated using the pseudo-first, pseudo-second order kinetic model and Weber-Morris intraparticle diffusion kinetic models, as described elsewhere [8].…”

“…However, the organic dyes can cause several damage and environmental issues, when they are not appropriately handle [3,4]. Noteworthy, the absorption of the sunlight by wastewater from textile dyes hinders light groups in an anionic organic dye might form weak interactions with iron particles on its surface [16].…”

“…Therefore, the surface charges should be modulated to produce a stronger electrostatic attraction to efficiently remove the anionic dye over iron-oxides particles. This type of dye adsorption with using on iron species is usually achieved by fixing the Fe particles onto a carbon material that gives a fast separation of the surface charge and its further regulation of the pollution [13,16]. Although, a complete chemical mechanism of dye removal and its adsorption rates improvement in the iron species have not been establish yet, the potential route for wastewater with dye organic molecules treatment in wastewater is needed.…”

“…In addition, the Acid Red 66 dye chemical structure contains nitrogen to nitrogen, i.e., -N=N-bonds with the aromatic rings mostly substituted by sulfonate groups. Therefore, the Acid Red 66 is very suitable to be absorbed by the Fe-based adsorbents possessing positive surface charge in the acidic solution media [16,19,20].…”