Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr (VI) ions

Abdelazeem S Eltaweil; Eman M Abd El-Monaem; Mohamed S Mohy-Eldin; Ahmed M Omer

doi:10.1038/s41598-021-96145-6

Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr (VI) ions

Sci Rep. 2021 Aug 16;11(1):16598. doi: 10.1038/s41598-021-96145-6.

Authors

Abdelazeem S Eltaweil¹, Eman M Abd El-Monaem², Mohamed S Mohy-Eldin³, Ahmed M Omer⁴

Affiliations

¹ Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt. abdelazeemeltaweil@alexu.edu.eg.
² Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
³ Polymer Materials Research Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City, P. O. Box: 21934, Alexandria, Egypt.
⁴ Polymer Materials Research Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City, P. O. Box: 21934, Alexandria, Egypt. amomar@srtacity.sci.eg.

Abstract

An efficient composite was constructed based on aminated chitosan (NH₂Cs), attapulgite (ATP) clay and magnetic Fe₃O₄ for adsorptive removal of Cr(VI) ions. The as-fabricated ATP@Fe₃O₄-NH₂Cs composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analyzer (TGA), Scanning Electron Microscope (SEM), Zeta potential (ZP), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller method (BET) and X-ray photoelectron spectroscope (XPS). A significant improve in the adsorption profile was established at pH 2 in the order of ATP@Fe₃O₄-NH₂Cs(1:3) > ATP@Fe₃O₄-NH₂Cs(1:1) > ATP@Fe₃O₄-NH₂Cs(3:1) > Fe₃O₄-NH₂Cs > ATP. The maximum removal (%) of Cr(VI) exceeded 94% within a short equilibrium time of 60 min. The adsorption process obeyed the pseudo 2nd order and followed the Langmuir isotherm model with a maximum monolayer adsorption capacity of 294.12 mg/g. In addition, thermodynamics studies elucidated that the adsorption process was spontaneous, randomness and endothermic process. Interestingly, the developed adsorbent retained respectable adsorption properties with acceptable removal efficiency exceeded 58% after ten sequential cycles of reuse. Besides, the results hypothesize that the adsorption process occurs via electrostatic interactions, reduction of Cr(VI) to Cr(III) and ion-exchanging. These findings substantiate that the ATP@Fe₃O₄-NH₂Cs composite could be effectively applied as a reusable adsorbent for removing of Cr(VI) ions from aqueous solutions.