|
|
Influence of reactivity on transport of metal ions in humic gels
Smitalová, Michaela ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
This diploma thesis deals with copper(II) ions diffusion in the humic hydrogels. The hydrogels were prepared from several samples of humic acids using different method and their isolation conditions from the original matrix. A selective blocking of functional groups (COOH, OH) was performed in the selected samples of humic acids. These reactive groups were selectively blocked using methylation agent trimethylsilyl-diazomethane. The success of performed methylation and functional groups blocking was verified using a FT-IR spectroscopy. There was carried out the set of diffusion experiments. The experimental arrangement was selected to enable an instantaneous planar source met-hod for data processing. The basis of this method was to determine the copper(II) ions con-centration distribution in the hydrogels. The method consists of slicing of the hydrogels after the diffusion experiments, extraction of the copper ions in the solution and determina-tion of concentration in the extracts from individual slices using UV-VIS spectroscopy. Based on the experimental data the effective diffusion coefficients were determined. The resulting values include both the effect of hydrogels structure and the effect of the reaction between Cu(II) ions and humic acids. There were prepared gels with defined portion of blocked functional groups for selected samples, which allowed to investigate the effect of reactivity on the copper ions diffusion without the significant changes in the gel structure (porosity). The blocking of functional groups reflected in a lower values of diffusion coefficients in comparison to the gels prepared from unmodified humic acids as follows. There was also confirmed the effect of humic acids isolation procedure and their properties on the diffusivity.
|
|
|
Reactivity-mapping studies on biopolymers in hydrogel forms
Smilek, Jiří ; Kislinger, Jiří (referee) ; Sedláček, Petr (advisor)
The diploma thesis is focused on the study of interactions between biopolymers and model probes in a hydrogel media utilizing diffusion processes. The main aim was to test and to optimize selected combination of diffusion methods (diffusion cells and unsteady diffusion) in study of interactions between biopolymers and organic dyes. Anionic (humic acids) and cationic (chitosan) representatives of biopolymers were utilized and methylene blue and methylene orange were used as a reactivity probe in the case of humic acids and chitosan, respectively. Another appreciable part of the work is represented by in-depth characterization of applied biopolymers and hydrogel samples by a wide range of analytical and physico-chemical methods (rheometry, UV-VIS, FT-IR etc.). Besides particular experimental results on studied systems, the diploma thesis provides both theoretical and practical background for subsequent applications of the innovative and full-automated method for reactivity mapping of biopolymers.
|
|
|
Study on reactivity of humic acids via method of diffusion cells
Hrubá, Pavla ; Weidlich,, Tomáš (referee) ; Sedláček, Petr (advisor)
The diploma thesis focuses on utilization of diffusion cells in reactivity mapping study on humic acids. In the experimental part, samples 6 humic acids of different origin or chemical modification were studied. All the samples were characterized by basic analytical and physico-chemical methods (elemental analysis, thermogravimetry, determination of acidity, spectrometry). Methylene blue was utilized as a model reactive probe and agarose gel as an inert support medium. An effect of interactions between humic acids and methylene blue on diffusivity of the dye in the hydrogel was determined and discussed.
|
|
|
Utilization of flow-coulometry in study of transport metal ions in humic gels
Kalina, Michal ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
This diploma thesis deals with the study of non-stationary diffusion of cupric ions in humic gels. The main objective of the work was the optimalization of conditions for using the electrochemical analyzer EcaFlow 150 GLP for the study of diffusion experiments. Next part was focused on reaching of constant concentration profiles of cupric ions in humic gel. Last aim of the study was the bond strength between cupric ions and humic acids. Diffusion was characterized by the values of the diffusion flux and cupric ions concentration profiles in humic gel. The data necessary for calculation were obtained by the electrochemical analyses of the extracts of each slice after diffusion on the EcaFlow 150 GLP. It has been proved that after application of several adjustment is this method suitable for the study of diffusion experiments. By using of different extraction agents was obtained the fractionalization of cupric ions according to the bond strength to humic acids.
|
|
|
Transport of Biomedical Active Compounds Through Porous Membranes
Vašíčková, Kateřina ; Smilková, Marcela (referee) ; Smilek, Jiří (advisor)
This bachelor thesis deals with a study of transport of biomedical active compounds through porous membranes. The main goal is to optimize a penetration method of micellar solutions with a solubilized dye and subsequently with solubilized drug. Cetyltrimethylammonium bromide is chosen as a surfactant and a nile red dye is used as a diffusion and fluorescence probe. Selected active compound is a nonsteroidal anti-inflammatory drug ketoprofen with analgesic and antipyretic effects. The diffusion processes are realized using Franz diffusion cells with polycarbonate membrane with a 2 µm size of poruses. The samples are withdrawn in a chosen time intervals and afterwards evaluated by a fluorescence correlation spectroscopy. Using this method, it is possible to screen the diffusion in time even in nanomolar concentrations of a fluorescence probe chosen. This thesis provides an overview of nile red behaviour in the micellar solutions of surfactant during diffusion processes. The experiment can be extended using an active compound, for instance using a ketoprofen as it is mentioned above.
|
|
|
Influence of properties of humic acids on diffusion of cupric ions in humic hydrogels
Král, Jan ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
Presented bachelor's thesis focuses on the study of diffusion of cupric ions in humic acid gels. The objective of the work was to assess how the properties effect diffusion in humic gels. In the experimental part, three samples of humic acids of different purity were studied. Method of instantaneous planar source diffusion was used to compare them. This methods was based on monitoring temporal evolution of diffusion profiles of cupric ions in gels. Copper ions were elected as diffusing medium because of their high affinity and strong bonds to humic acids.
|
|
|
Study of reactivity and mobility of Cu(II) ions in humic hydrogels
Hegr, Martin ; Solná, Irena (referee) ; Klučáková, Martina (advisor)
This bachalor´s thesis is focused on the study of diffusion of cupric ions in gel of humic acid. The objective of this thesis was to investigate the effect of the concentration of cupric ions supply source duration of diffusion on transport through the gel. Cupric ions was used like the diffusion medium. Cupric ions are thanks their high affinty for the humic acids ideal on the diffusion through the humic gel. Three different concentration of CuCl2 were compared, specifically 0,05M, 0,1M and 1M, and also three different times, specifically 10 hours, 1 day and 3 days. To compare them was used method of diffusion couple. The data necessary for calculation were obtained by UVVIS spectrophotometry.
|
|
|
Transport properties of humic gels
Sárová, Michaela ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
This bachelor’s thesis is focused on study of transport properties of humic gels. For research of these properties was used diffusion method of organic dyes in diffusion cells which is based on spectrophotometric monitoring of concentration changes depending on time. Dyes used in the experiment were specifically methylene blue and rhodamine 6G and diffusion experiments were performed on an agarose hydrogel without the addition of humic acid, with the addition of unmethylated humic acid and then with the addition of methylated humic acid. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. It has been found that the presence of humic acid in agarose hydrogel greatly influences the transport of dyes.
|
|
|
Diffusion in humic gels.
Královič, Michal ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focuses on study of heavy metals diffusion in humic gels. The objective of the work was to verify, whether the diffusion is influenced by methylation of humic acid. Cupric and nickel cation was used in this thesis. Absorbance of solutions in acceptor and donor diffusion cell part was measured spektrofotometrically.
|
|
|
influence of physical conditions on diffusion processes in humic gels
Marvan, Jan ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
Diploma thesis is based on diffusion processes of copper (II) ions to humic gels obtained from lignite. Solutions with various concentrations and acidity were exposed to diffusion for exact time 24 hours. After the diffusion was ended the copper (II) ionic concentration profiles of tubular gels were create and calculated total diffusion flux. The experiment showed that the higher acidity of copper (II) solution decrease an amount of immobilized Cu2+ ions to the humic gels. In comparison concentration/pH: concentration of the solution has higher influence on sorption metal ions than change of the pH.
|
guest ::
