Recycling of precious materials by modified electrospun membranes


Zeytuncu Gökoğlu B. , Şengür Taşdemir R. , Tanc B. , AKTAŞ S., Koyuncu İ.

Desalination and Water Treatment, vol.211, pp.439-447, 2021 (Journal Indexed in SCI Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 211
  • Publication Date: 2021
  • Doi Number: 10.5004/dwt.2021.26748
  • Title of Journal : Desalination and Water Treatment
  • Page Numbers: pp.439-447
  • Keywords: Adsorption, Electrospinning, Gold, Keratin, Nanofiber membrane, Platinum

Abstract

© 2021 Desalination Publications. All rights reserved.In this study, adsorption of gold (Au) and platinum (Pt) ions by electrospun polyacrylonitrile (PAN) natural keratin-modified membranes with high sulfur content and affinity toward precious metals were investigated. Different adsorption parameters, sorbent amount, contact time, tem-perature and pH of solution on adsorption (%) were studied in detail in batch sorption. First, a PAN nanofiber membrane was fabricated by an electrospinning technique as a low-cost method for producing nanofiber membranes and was then modified with the natural keratin (human hair) by hydrolysis in a basic solution. A PAN–keratin nanofiber membrane was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy (FTIR and SEM, respec-tively). FTIR verified the modification of PAN with keratin in which the spectrum of the resulting membrane showed significant changes, by using this modified nanofiber membrane, Au adsorp-tion of 99% was achieved while the Pt adsorption showed a maximum of 37%. The reason for this finding may be because the electronegativity of Au is higher than Pt. When the adsorption iso-therms were investigated, it was noted that the Langmuir isotherm fit better than the Freundlich isotherm. 1.0 M thiourea solution was used as a desorption reagent for both Au and Pt ions. Reusability studies showed that the adsorption capacity can remain up to 90 % after four times of usage. This finding indicates that the adsorption process of precious ions onto the electrospun membrane is a monolayer adsorption process.