Journal of Particle Science and Technology

Journal of Particle Science and Technology

Application of modified bentonite for efficient water purification: A case of Cr(VI) adsorption

Document Type : Research Article

Authors
Zahra Jelodari 1
Maryam Khajenoori 1
Pouya Mottahedin 2
1 Faculty of Chemical Petroleum and Gas Engineering, Semnan University, Semnan, Iran
2 Department of Chemical Engineering, Faculty of Engineering, University of Garmsar, Garmsar, Iran
10.22104/jpst.2025.7462.1273
Abstract
This study explores the use of acid-activated bentonite as an efficient adsorbent for removing hexavalent chromium (Cr(VI)) from water. Acid activation enhances the surface area and adsorption capacity of bentonite, improving its water treatment efficiency. Various techniques, including BET, FT-IR, XRD, XRF, and SEM, were used to analyze structural and compositional changes after activation. Adsorption experiments showed that under optimal conditions - room temperature, 0.1 ppm Cr(VI), and 1 g of acid-activated bentonite - 100 % removal was achieved. The adsorption followed the Langmuir isotherm with a maximum capacity of 0.122 mg.g-1. Kinetic studies confirmed a pseudo-second-order reaction model (R² = 0.99), indicating a chemisorption mechanism. Thermodynamic analysis showed the process is spontaneous and exothermic, requiring no external energy input. Groundwater tests from the Forumad region (Semnan Province) compared raw and acid-modified bentonite, revealing a 92 % Cr(VI) removal efficiency with the modified form, reducing contamination to safe levels. These results highlight acid-activated bentonite as a cost-effective, eco-friendly adsorbent for water purification, demonstrating its real-world potential for ensuring safer drinking water.

Graphical Abstract

Application of modified bentonite for efficient water purification: A case of Cr(VI) adsorption

Highlights

  • Enhanced adsorption efficiency of acid-activated bentonite for Cr(VI) removal from water.
  • 100 % Cr(VI) removal under optimal conditions.
  • Fits Langmuir isotherm and pseudo-second order kinetics.
  • Spontaneous and exothermic processes, requiring no external energy.
  • 92 % Cr(VI) removal from groundwater in Iran’s Forumad region.

Keywords
Adsorption
Bentonite
Acid-activated
Hexavalent chromium
Thermodynamic and kinetic study
Subjects

Copyright © 2024 The Author(s). Published by IROST.

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Journal of Particle Science and Technology
Volume 10, Issue 2
December 2024
Pages 117-128

  • Receive Date 16 March 2025
  • Revise Date 20 April 2025
  • Accept Date 08 May 2025