Fabrication of nano-graphene oxide assisted hydrotalcite/chitosan biocomposite: An efficient adsorbent for chromium removal from water

Recently, nanomaterials based adsorbents play a prominent role in the removal of toxic ions from aqueous solution. Hence in the present study, nano-graphene oxide (n-GO) fabricated hydrotalcite (n-GO@HT) composite was prepared by hydrothermal method for chromium removal. To improve the mechanical strength and chromium removal capacity, GO@HT composite was reinforced with chitosan (CS) to form hybrid composite namely n-GO@HTCS biocomposite. The synthesized biocomposite was characterized using various instrumental techniques like FTIR, SEM, TEM and EDAX with mapping analysis. To get the maximum chromium retention, the various sorption experiments like agitation time, dosage, pH, competing ions and temperature were optimized. The sorption capacity (SC) of n-GO@HTCS biocomposite was found to be 42.64 mg/g within 50 min. The obtained equilibrium data was explained with Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms wherein the chromium sorption process was best fitted with Langmuir isotherm. The thermodynamic results prove that the chromium sorption of n-GO@HTCS biocomposite was endothermic and spontaneous. The chromium sorbed n-GO@HTCS biocomposite could be easily regenerated with 0.1 M NaOH. The synthesized n-GO@HTCS biocomposite was also utilized in the field conditions. (C) 2019 Elsevier B.V. All rights reserved.