Nitrate adsorption onto surface-modified red mud in batch and fixed-bed column systems: equilibrium, kinetic, and thermodynamic studies

Ebrahim Allahkarami, Amirreza Azadmehr, Fahimeh Noroozi, Shayan Farrokhi, Mika Sillanpää

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

This research aimed to develop a novel composite as a low-cost adsorbent for the removal of nitrate ion from aqueous solutions. The characterization of this composite (composition of red mud with dimethyldioctadecylammonium bromide (DDAB)) was performed by XRF, XRD, FTIR, and BET analyses. The most influential variables on nitrate adsorption, including contact time, solution acidity, adsorbent amount, and temperature were studied. The maximum amount of nitrate adsorbed onto the prepared adsorbent was obtained at pH 5.5 and contact time 30 min. The heterogeneous adsorption occurred during the uptake of nitrate. The results of kinetic study revealed that intra-particle diffusion was the major limitation for nitrate adsorption rate. The values of thermodynamic parameters illustrate the non-spontaneous, associative, and exothermic adsorption process. Increasing the temperature enhances the tendency of the process to non-spontaneously. Research on fixed-bed column has been done under different initial nitrate concentrations. The adsorption capacity of nitrate was increased with an increase in the initial concentration of nitrate. The results of column data were successfully explained using the Thomas and Yoon–Nelson models.

Original languageEnglish
Pages (from-to)48438-48452
Number of pages15
JournalEnvironmental Science and Pollution Research
Volume29
Issue number32
DOIs
Publication statusPublished - Jul 2022

Keywords

  • Adsorption
  • DDAB
  • Fixed-bed column
  • Nitrate ion
  • Surface-modified red mud

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Health, Toxicology and Mutagenesis

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