Chemical Papers

, Volume 67, Issue 5, pp 497–508

Removal of heavy metal ions from aqueous solutions using low-cost sorbents obtained from ash


  • Maria Harja
    • Department of Chemical Engineering“Gheorghe Asachi” Technical University of Iasi
  • Gabriela Buema
    • Department of Chemical Engineering“Gheorghe Asachi” Technical University of Iasi
  • Daniel Mircea Sutiman
    • Department of Chemical Engineering“Gheorghe Asachi” Technical University of Iasi
    • Department of Environmental Engineering and Management, Faculty of Chemical Engineering and Environmental Protection“Gheorghe Asachi” Technical University of Iasi
Original Paper

DOI: 10.2478/s11696-012-0303-7

Cite this article as:
Harja, M., Buema, G., Sutiman, D.M. et al. Chem. Pap. (2013) 67: 497. doi:10.2478/s11696-012-0303-7


This study’s main objective was the development of effective low-cost sorbents for the removal of heavy metal ions from aqueous solutions. The influence of different factors on the sorption capacity of ash and modified ash as low-cost sorbents obtained by different methods was investigated. The synthesis of new ash-based materials was carried out at ambient temperature (20°C), 70°C, and 90°C, respectively, in an alkaline medium with NaOH concentrations of 2 M and 5 M, respectively, corresponding to a mixture with solid/liquid ratios of 1: 3 and 1: 5, respectively. The prepared materials (sorbents) were characterised by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffraction, and BET surface measurement. Adsorption isotherms were determined using the batch equilibrium method. The results showed that these types of new materials displayed a good capacity to remove copper, nickel, and lead ions (29.97 mg of Cu2+ per g of sorbent, 303 mg of Ni2+ per g of sorbent, and 1111 mg of Pb2+ per g of sorbent) from aqueous solutions. The modified materials were prepared using an alkaline attack (a recognised method used in previous studies), but Romanian ash from a thermal power plant was studied for the above purpose for the first time. Hence, the factors which affect the sorption capacity of the prepared low-cost sorbents were determined and their behaviour was explained, taking into account the composition and structure of the new materials.


ashcharacterisationheavy metallow-cost sorbentsorbent synthesis

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© Institute of Chemistry, Slovak Academy of Sciences 2012