Removal of Cu2+, Pb2+ and Cr6+ from aqueous solutions using a chitosan/graphene oxide composite nanofibrous adsorbent

Abstract

A novel electrospun chitosan/graphene oxide (GO) nanofibrous adsorbent was successfully developed by an electrospinning process. The adsorption behaviors of Cu²⁺, Pb²⁺ and Cr⁶⁺ metal ions from aqueous solutions using chitosan/GO nanofibers were investigated. The composite nanofibers were characterized by FTIR and SEM and TEM analysis. Kinetic and equilibrium studies showed that the experimental data of Cu²⁺, Pb²⁺ and Cr⁶⁺ were best described by double-exponential kinetic and Redlich–Peterson isotherm models. The maximum monolayer adsorption capacity of Pb²⁺, Cu²⁺and Cr⁶⁺ metal ions using chitosan/GO nanofibers was found to be 461.3, 423.8 and 310.4 mg g⁻¹ at an equilibrium time of 30 min and temperature of 45 °C. Evaluation of the thermodynamic parameters (ΔG° < 0, ΔH° > 0 and ΔS° > 0) showed that the nature of the metal ions sorption by chitosan/GO nanofibers was endothermic and spontaneous. The reusability studies indicated that the chitosan/GO nanofibers could be reused frequently without almost any significant loss in adsorption performance. This study provides a promising chitosan/GO nanofibrous adsorbent with an efficient adsorption property for heavy metal ions removal.