Selective adsorption of Cr(VI) ions from aqueous solutions using Cr⁶⁺-imprinted Pebax/chitosan/GO/APTES nanofibrous...

In the present study, a novel Cr⁶⁺-imprinted Pebax/chitosan/GO/APTES nanofibrous adsorbent (Cr⁶⁺-PCGA) was prepared and its performance was compared with PCGA nanofibers for selective sorption of Cr(VI) ions from aqueous solutions. The prepared nanofibers were characterized using FTIR, SEM and EDAX analysis. The influence of batch sorption experiments including GO/APTES content, pH, contact time, Cr(VI) initial concentration and temperature on the Cr(VI) sorption efficiency using synthesized nanofibers was investigated. The Cr(VI) sorption data were well described using pseudo-second-order kinetic and Redlich-Peterson isotherm models. The maximum sorption capacities of Cr⁶⁺-PCGA and PCGA nanofibers for Cr(VI) ions sorption were found to be 204.5 and 550.5mgg^-1, respectively. Thermodynamic studies indicated an endothermic and spontaneous nature of Cr(VI) ions sorption using both Cr⁶⁺-PCGA and PCGA nanofibers. The selectivity coefficient values of Cr(VI)/Pb(II), Cr(VI)/Cu(II) and Cr(VI)/Ni(II) indicated the higher selectivity of Cr⁶⁺-PCGA nanofibrous adsorbent for Cr(VI) ions separation compared to PCGA nanofibers. The good stability and reusability of Cr⁶⁺-PCGA nanofibrous adsorbent for five sorption/desorption cycles promised a higher potential of ion-imprinted nanofibers for separation of metal ions from aqueous systems in a large scale.