Highly-efficient capture of chromium (VI) ions on electrospun polyacrylonitrile/diaminoglyoxime nanofiber: thermal stability, decomposition kinetics and tensile strength

Abstract

Abstract In this study, a new polyacrylonitrile/diaminoglyoxime-based nanofiber was developed using electrospinning thanks to their outstanding chemical-mechanical properties used as effective adsorbents for the Cr(VI) removal without any secondary pollution. However, thermal stability and degradation of these nonpolymeric-mats could limit their application. The electrospun polyacrylonitrile with different percentages of diaminoglyoxime (%) nanofibers have their average diameters between 70 and 85 nm. The DSC technique was used to characterize the thermal stability of the manufactured polyacrylonitrile/diaminoglyoxime nanofiber. Decomposition kinetic parameters of the mats via the non-isothermal approaches and thermodynamic parameters (ΔG#, ΔH# and ΔS#) were determined. Polyacrylonitrile/diaminoglyoxime(30%) reached maximum adsorption capacity of 348.7 mg g−1 for Cr(VI) ions. After conducting the adsorption–desorption test for 20 times, polyacrylonitrile/diaminoglyoxime(30%) nanofiber exhibited excellent regeneration and stable desorption efficiency of over 73%. Compared with complicated industrial-sized chemicals for adsorbing Cr(VI), the nanofiber mat proposed herein is a simple one-step electrospinning process, which is extremely successful for industrial applications, cheap and without harmful by-products. Polyacrylonitrile/diaminoglyoxime (30%) was proposed as an appropriate material to adsorb Cr(VI) ions.