|
|
Cr(VI) adsorption to synthetic mixture of soil minerals
Pehová, Edita ; Veselská, Veronika (advisor) ; Tomáš, Tomáš (referee)
Due to its toxicity, the Cr(VI) is known as a substance with negative effects on the environment. Understanding of Cr mobility, speciation and its toxicity helps to prevent negative impacts of this contaminant in soils, natural waters and atmosphere. This diploma thesis deals with a mechanism of Cr(VI) adsorption on to mixture of selected soil minerals as quartz, kaolinite and ferrihydrite based on mineralogical and chemical composition of the real contaminated soil. Main goal of diploma thesis is to test the selected surface complexation model, the DLM (diffuse layer model), which could be able to capture the process of Cr(VI) adsorption in natural heterogenic systems like soils. Component additivity approach (CA) was tested. The adsorption experiments were performed with three different concentrations of Cr(VI) (10-4, 10-5, 10-6) as a function of pH at different ionic strengths. Obtained data were used for modelling of adsorption edges and for DLM testing. Results confirmed, that Cr(VI) adsorption in synthetic mixture of enlarged soil minerals, is controlled mainly by presence of Fe-(oxy)hydroxides. The mechanistic surface complexation models used for modelling of Cr(VI) adsorption onto synthetic mineral mixtures, based on real mixed ratios of representative mineral phases in soils, can be useful for prediction of processes responsible for transport and retention of the Cr(VI) in soils.
|
guest ::
