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Diffusion processes in modified humic gels
Grunt, Jakub ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis presents a study on diffusion of cupric ions in humic acid gels. A total of four types of samples were made during a modified preparation of gels. Humic acids were dissolved either in sodium hydroxide or in the solution of sodium triphosphate. Subsequently, hydrochloric acid and magnesium chlorid were used for "precipitation" of the gels. Gained samples differed particularly in the nature of interactions forming their gel structures. All the samples were subjected to diffusion experiments. Two different methods – constant-source diffusion and immediate planar source diffusion – were used to assign the diffusion coefficients. Both these methods were based on monitoring how the diffusion profiles of cupric ions in gels develop in time and on assigning the overall diffusion flow. The aim of the thesis was to assess the impact of gel preparation procedure and resultant structure on diffusion coefficients of cupric ions and their transport attributes in gels in general. Two different methods of diffusion inquiry were chosen particularly to assess the impact of cupric ion concentration on the diffusion coefficient.
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Diffusion of cupric ions in humic hydrogels
Grunt, Jakub ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
Presented diploma thesis focuses on the study of diffusion of cupric ions in humic acid hydrogels. A total of eight different hydrogels were prepared by dissolving the humic acids with sodium hydroxide and sodium triphosphate. For the purpose of precipitation and cross linking, hydrochloric acid and chlorides of magnesium, calcium and iron were used during a modified preparation of gels. Different gel-forming interactions were achieved by modifying the preparation of hydrogel systems. The aim of the thesis was to assess the effect of gel preparation procedure on the transport properties of the gels. Therefore, diffusion coeficients were determined for all samples. Two different methods - constant-source diffusion and instantaneous planar source diffusion - were used to assign the diffusion coefficients. Methods differ in source concentrations of cupric ions and are suitable for assessing the impact of the concentration on the diffusion coefficient. Both these methods were based on monitoring temporal evolution of diffusion profiles of cupric ions and on assigning the overall diffusion flow. Copper ions were elected as diffusing medium because of their high affinity and strong binding to humic acids. Measurements show that gels prepared using polyphosphate allow slightly faster diffusion of cupric ions and that the constant-source method provides higher diffusion coefficients in comparison to instantaneous planar source method.
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Diffusion of cupric ions in humic hydrogels
Grunt, Jakub ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
Presented diploma thesis focuses on the study of diffusion of cupric ions in humic acid hydrogels. A total of eight different hydrogels were prepared by dissolving the humic acids with sodium hydroxide and sodium triphosphate. For the purpose of precipitation and cross linking, hydrochloric acid and chlorides of magnesium, calcium and iron were used during a modified preparation of gels. Different gel-forming interactions were achieved by modifying the preparation of hydrogel systems. The aim of the thesis was to assess the effect of gel preparation procedure on the transport properties of the gels. Therefore, diffusion coeficients were determined for all samples. Two different methods - constant-source diffusion and instantaneous planar source diffusion - were used to assign the diffusion coefficients. Methods differ in source concentrations of cupric ions and are suitable for assessing the impact of the concentration on the diffusion coefficient. Both these methods were based on monitoring temporal evolution of diffusion profiles of cupric ions and on assigning the overall diffusion flow. Copper ions were elected as diffusing medium because of their high affinity and strong binding to humic acids. Measurements show that gels prepared using polyphosphate allow slightly faster diffusion of cupric ions and that the constant-source method provides higher diffusion coefficients in comparison to instantaneous planar source method.
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Diffusion processes in modified humic gels
Grunt, Jakub ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis presents a study on diffusion of cupric ions in humic acid gels. A total of four types of samples were made during a modified preparation of gels. Humic acids were dissolved either in sodium hydroxide or in the solution of sodium triphosphate. Subsequently, hydrochloric acid and magnesium chlorid were used for "precipitation" of the gels. Gained samples differed particularly in the nature of interactions forming their gel structures. All the samples were subjected to diffusion experiments. Two different methods – constant-source diffusion and immediate planar source diffusion – were used to assign the diffusion coefficients. Both these methods were based on monitoring how the diffusion profiles of cupric ions in gels develop in time and on assigning the overall diffusion flow. The aim of the thesis was to assess the impact of gel preparation procedure and resultant structure on diffusion coefficients of cupric ions and their transport attributes in gels in general. Two different methods of diffusion inquiry were chosen particularly to assess the impact of cupric ion concentration on the diffusion coefficient.
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