Alginate coated layered double hydroxide/reduced graphene oxide nanocomposites for removal of toxic As (V) from wastewater

Abstract

In this study, Sodium Alginate coated Fe–Al layered double hydroxide/reduced Graphene Oxide (FAH-rGO/SA) nanoadsorbents were synthesized through hydrothermal and ex-situ polymerization process and investigated for their removal efficiency of As (V) ions. The synthesized adsorbents were analyzed by XRD (X-ray diffraction), FESEM (Field Emission Scanning Electron Microscopy), HRTEM (High Resolution Transmission Electron Microscopy), and FTIR (Fourier Transform Infrared spectroscopy). N2 adsorption-desorption analysis was employed to determine the surface area (151.35 m2 g−1) and porosity properties of the nanocomposites by BET and BJH techniques. Equilibrium batch techniques were implemented to study the different parameters of adsorption such as adsorbent dosage, contact time, pH, adsorption isotherms and kinetics and their results were reported. The adsorption isotherm was perfectly suited to the Langmuir isotherm model, which denotes the adsorption process occurred by the monolayer arrangement of adsorbent ions. The calculated qmax (maximum adsorption capacity) of FAH-rGO, FAH-rGO/SA-1 and FAH-rGO/SA-4 adsorbents for As (V) adsorption were determined to be 115.39, 151.29, and 190.84 mg g−1, respectively at room temperature. Kinetic studies of As (V) adsorption were discussed by Pseudo kinetic models and the adsorption process pursues the Pseudo second order model with correlation co-efficient greater than 0.97. Thus, these results indicate that, high wt% of SA in FAH-rGO nanocomposite demonstrated highest removal efficiency (>98%) on As (V) ions with simple magnetic separability and effective recyclability and used as efficient adsorbent for the removal of As (V) ions from wastewater.