Thallium(I) sorption using Prussian blue immobilized in alginate capsules

Carbohydr Polym. 2014 Jan:99:517-26. doi: 10.1016/j.carbpol.2013.08.076. Epub 2013 Sep 1.


Prussian blue (PB) was immobilized in alginate capsules. The composite sorbent was used for the recovery of Tl(I) ions from slightly acidic solutions: optimum pH being close to 4. The sorption isotherm can be described by the bi-site Langmuir sorption isotherm. This means that the metal ion can be bound through two different sorption sites: one having a strong affinity for Tl(I) (probably PB), the other having a lower affinity (probably the encapsulating material). The kinetics are described by either the pseudo-second order rate equation or the Crank's equation (resistance to intraparticle diffusion). The ionic strength (increased by addition of NaCl, KCl or CaCl₂) slightly decreased sorption capacity. The SEM-EDX analysis of PB-alginate capsules (before and after Tl(I) sorption) shows that the PB is homogeneously distributed in the capsules and that all reactive groups remain available for metal binding.

Keywords: Alginate; SEM-EDX analysis; Sorption isotherms; Thallium; Uptake kinetics.

MeSH terms

  • Adsorption
  • Alginates / chemistry*
  • Capsules
  • Ferrocyanides / chemistry*
  • Glucuronic Acid / chemistry
  • Hexuronic Acids / chemistry
  • Hydrogen-Ion Concentration
  • Kinetics
  • Microscopy, Electron, Scanning
  • Osmolar Concentration
  • Spectrometry, X-Ray Emission
  • Thallium / isolation & purification*
  • Thermodynamics
  • Water Pollutants, Chemical / isolation & purification*


  • Alginates
  • Capsules
  • Ferrocyanides
  • Hexuronic Acids
  • Water Pollutants, Chemical
  • thallium chloride
  • Glucuronic Acid
  • Thallium
  • ferric ferrocyanide