Materials (Aug 2020)

Eco-Friendly Materials Obtained by Fly Ash Sulphuric Activation for Cadmium Ions Removal

  • Gabriela Buema,
  • Nicoleta Lupu,
  • Horia Chiriac,
  • Tiberiu Roman,
  • Marieta Porcescu,
  • Gabriela Ciobanu,
  • Daniela Vasilica Burghila,
  • Maria Harja

DOI
https://doi.org/10.3390/ma13163584
Journal volume & issue
Vol. 13, no. 16
p. 3584

Abstract

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Wastes are the sustainable sources of raw materials for the synthesis of new adsorbent materials. This study has as objectives the advanced capitalization of fly ash, by sulphuric acid activation methods, and testing of synthesized materials for heavy metals removal. Based on the previous studies, the synthesis parameters were 1/3 s/L ratio, 80 °C temperature and 10% diluted sulphuric acid, which permitted the synthesis of an eco-friendly adsorbent. The prepared adsorbent was characterized through SEM, EDX, FTIR, XRD and BET methods. Adsorption studies were carried out for the removal of Cd2+ ions, recognized as ions dangerous for the environment. The effects of adsorbent dose, contact time and metal ion concentrations were studied. The data were tested in terms of Langmuir and Freundlich isotherm and it was found that the Langmuir isotherm fitted the adsorption with a maximum adsorption capacity of 28.09 mg/g. Kinetic data were evaluated with the pseudo-first-order model, the pseudo-second-order model and the intraparticle diffusion model. The kinetics of cadmium adsorption into eco-friendly material was described with the pseudo-second-order model, which indicated the chemisorption mechanism.

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