Biosorpce trojmocného a šestimocného chromu z vodných roztoků pomocí biomasy na bázi rostlin a řas.

Abstract

In this thesis we investigated the capability of plant Reynoutria japonica and algae Spirogyra sp. to bind Cr(III) and Cr(VI) ions from aqueous solutions. The object of this research was to study effect of pH and activation and its influence on the time profile sorption and sorptions isoterms. From these results was created matematical models, pseudo second order model, Langmuir and Freundlich models. It was also investigated the possibility of regeneration biosorbents by desorption proces. The study also dealed with the reduction of anions of Cr(VI) at determinated pH of chromium solution in presence of biosorbent. From analytical metods the biosorbents were subjected to FTIR, SEM and BET analysis. The results showed that pH has a significant ifluence on the proces of biosorption. For the sorption of Cr(III) was the most suitable the pH 5. The best results was achieved by Reynoutria japonica activated in 0,1 M NaOH and Spirogyra sp activated in 0,1 M HCl. For the sorption of Cr(VI) was the most suitable the pH 2-4. The best results were achieved by Reynoutria japonica activated in 0,1 M HCl. The biosorbent of Spirogyra sp has the highest removal efficiency of Cr(VI) at pH 2 and activated in 0,1 M HCl. The ability of reduction Cr(VI) to Cr(III) at determinated condition in presence of biosorbents was found. From the study of the sorption isoterms was revealed that biosorbent from Spirogyra sp. is suitable for sorption of Cr(III) and Cr(VI) at a concentration < 10 mg/l, because of small surface area. Reynoutria japonica is suitable for sorption of Cr(III) and Cr(VI) at a concentration > 10 mg/l. The desorption was performed with 0,5 M H2SO4 for selected biosorbents. The desorption of Cr(III) was not successful, because Cr(III) ions are probably binded much stronger bond than the bond of physical adsorption. Desorption of Cr(VI) was successful in 80% by Reynoutria japonica. Spirogyra sp failed in desorption process.