Adsorption of As(V) ions from aqueous solution by carboxymethyl cellulose incorporated layered double hydroxide/reduced graphene oxide nanocomposites: Isotherm and kinetic studies

Efficient nanocomposite adsorbents were synthesized based on carboxymethyl cellulose (CE) incorporated Fe-Al layered double hydroxide reduced graphene oxide (FAH-rGO/CE) for the adsorption of Arsenate (As (V)) ions in wastewater. Synthesized products were characterized by XRD (X-ray diffraction), FESEM (Field Emission Scanning Electron Microscopy), HRTEM (High Resolution Transmission Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy) and N-2 adsorption-desorption analysis. The incorporation of CE moieties on FAH-rGO composites evidently improved the active sites on boundary layer and As (V) removal capacity (98%) thereby enhancing the surface area of composites (156.24 m(2) g(-1)). Various parameters affecting the adsorption such as adsorbent dosages (0.01-0.1 g/L), contact time of adsorption (60-600 min) and effect of pH (2-11) were optimized using batch adsorption techniques. Adsorption isotherms were well fitted to the Langmuir isotherm model (correlation coefficient R-2 > 0.9991) to prove the monolayer adsorption of As (V) ions on the adsorbent surface. The maximum adsorption capacity (q(max)) of FAH-rGO, FAH-rGO/CE-1 and FAH-rGO/CE-4 were found to be 115.39, 170.36 and 258.39 mg g(-1), respectively. Adsorption kinetics was calculated by following the pseudo-second-order model with high correlation coefficient (R-2 >= 0.9996) value. In addition, the effect of pH, FTIR and EDS analysis revealed that the possible mechanism between the As (V) and CE composites was the electrostatic interactions with -OH and -COOH groups. Furthermore, FAH-rGO/CE adsorbent exposed good reusability even after five consecutive cycles (from 96% to 88%) with high stability. Thus, synthesized FAH-rGO/CE composites could be potentially used as an efficient adsorbent for As (V) adsorption in wastewater. (C) 2022 The Author( s ). Published by Elsevier B.V.

Automated summary

Efficient nanocomposite adsorbents based on carboxymethyl cellulose incorporated Fe-Al layered double hydroxide reduced graphene oxide were synthesized for the adsorption of Arsenate ions in wastewater. The incorporation of carboxymethyl cellulose improved the active sites and adsorption capacity of the composites. The adsorption parameters and kinetics were optimized, and the possible mechanism between Arsenate ions and the composites was electrostatic interaction. The synthesized nanocomposite adsorbents showed good reusability and stability.