Diffusion processes in modified humic gels

Abstract

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