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theses

I utilize the concept of specific polarizability (cs), represented as the ratio of mineral-fluid interface polarization per pore-normalized surface area Sp, to emphasize the influence of clay mineralogy and fluid chemistry on complex conductivity (CC) measurements. CC measurements were performed on kaolinite- and illite- sand mixtures as a function of varying ethanol (EtOH) concentration (10% and 20% v/v). Specific surface area of each clay type and Ottawa sand was determined by nitrogen gas adsorption-BET method. I also calculated porosity and saturation of each mixture based on weight loss of dried samples. Debye decomposition, a phenomenological model, was applied to the CC data to determine normalized chargeability (mn). The cs¬ estimates from previous CC measurements for bentonite-sand mixtures were compared with our dataset. The cs for all sand-clay mixtures decreased as the EtOH concentration increased from 0% to 10% to 20%. We observe similar responses to clay-driven polarization for all sand-clay mixtures. Analysis of variance (ANOVA) with a level of significance α = 0.05 found that suppression in cs responses with increasing EtOH concentration statistically vary for all sand-clay mixtures but the confidence level for cs is low. On the other hand, real conductivity showed only small changes with increasing EtOH concentration from 10% to 20%. The cs estimates reflect the sensitivity of CC measurements to alteration in surface chemistry at the available surface adsorption sites (internal and external) for different clay types assumed to result from chemical ion exchange at clay surface and kinetic reactions in the electrical double layer of the clay-water-EtOH media.

ETD_6874

M.S.

Includes bibliographical references

by Sundeep Sharma

doi:10.7282/T3N87CV5

ETD graduate

The author owns the copyright to this work.