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Specific polarizability of sand–clay mixtures with varying ethanol concentration
Author(s) -
Sharma Sundeep,
Slater Lee,
Ntarlagiannis Dimitrios,
Werkema Dale,
Szabo Zoltan
Publication year - 2017
Publication title -
near surface geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.639
H-Index - 39
eISSN - 1873-0604
pISSN - 1569-4445
DOI - 10.3997/1873-0604.2017049
Subject(s) - illite , polarizability , conductivity , adsorption , mineralogy , clay minerals , saturation (graph theory) , kaolinite , chemistry , induced polarization , hydraulic conductivity , analytical chemistry (journal) , porosity , electrical resistivity and conductivity , geology , soil science , chromatography , soil water , organic chemistry , mathematics , engineering , combinatorics , molecule , electrical engineering
We utilise a concept of specific polarizability( c s ) , represented as the ratio of mineral‐fluid interface polarization per pore‐normalised surface areaS p , to demonstrate the influence of clay‐organic interaction on complex conductivity measurements. Complex conductivity measurements were performed on kaolinite‐ and illite‐sand mixtures as a function of varying ethanol (EtOH) concentration (10% and 20% v/v). The specific surface area of each clay type and Ottawa sand was determined by nitrogen‐gas‐adsorption Brunauer‐Emmett‐Teller method. We also calculated the porosity and saturation of each mixture based on weight loss of dried samples. Debye decomposition, a phenom‐enological model, was applied to the complex conductivity data to determine normalised chargea‐bility( m n ) . Specific polarizability estimates from previous complex conductivity measurements for bentonite‐sand mixtures were compared with our dataset. Thec sfor all sand–clay mixtures decreased as the EtOH concentration increased from 0% to 10% to 20% v/v. We observe similarc sresponses to EtOH concentration for all sand–clay mixtures. Analysis of variance with a level of significance a = 0.05 suggests that the suppression inc sresponses with increasing EtOH concentration was statistically significant for all sand–clay mixtures. On the other hand, real conductivity showed only 10% to 20% v/v changes with increasing EtOH concentration. Thec sestimates reflect the sensitivity of complex conductivity measurements to alteration in surface chemistry at available surface adsorption sites for different clay types, likely resulting from ion exchange at the clay surface and associated with kinetic reactions in the electrical double layer of the clay‐water‐EtOH media. Our results indicate a much larger influence of specific surface area and ethanol concentration on clay‐driven polarization relative to changes in clay mineralogy.