Low-rank coals as precursors of effective carbonaceous adsorbents for the removal of Rhodamine B

Bazan-Wozniak A., Nosal-Wiercińska A., YILMAZ S., Pietrzak R.

Journal of Molecular Liquids, vol.389, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 389
  • Publication Date: 2023
  • Doi Number: 10.1016/j.molliq.2023.122949
  • Journal Name: Journal of Molecular Liquids
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, Chimica, Compendex, INSPEC
  • Keywords: Activated carbon, Adsorption, Chemical activation, Desorption, Mechanism, wastewater treatment Rhodamine B
  • Çanakkale Onsekiz Mart University Affiliated: Yes


This article presents the potential of two activated carbons obtained through the chemical activation of low-rank coals from the collieries Labin and Spitsbergen using potassium hydroxide for the adsorption of Rhodamine B dye. The results showed that the obtained adsorbents exhibit a mesoporous texture, and the acidic-basic character of the synthesized adsorbents depends on the starting material. The pseudo-second order kinetic model provided the best fit to the experimental results, indicating that the adsorption process occurred following a chemical process. On the other hand, the Langmuir adsorption isotherm showed the best fit, indicating monolayer adsorption. The Langmuir adsorption isotherm exhibited a high maximum adsorption capacity, which was 175 mg/g and 82 mg/g. Negative values of the Gibbs free energy indicating that the removal of Rhodamine B could be thermodynamically favorable due to the spontaneous nature of the adsorption. The efficiency of Rhodamine B removal by the obtained activated carbons depends on the functional groups present on the surface of the synthesized adsorbents, as well as their porous structure. In turn, desorption studies showed that the most effective eluent was the 0.1 M hydrochloric acid solution.