A Protein-Retention Method for Specific Surface Area Determination in Swelling Clays

Standard methods have been developed to measure the specific surface area (SSA) of clays, including methylene blue (MB) methods, but have limitations. This study focused on the development of a new method, the protein-retention (PR) method, for the SSA measurement of soil and its comparison with standard tests and published values. MB stain, MB titration, and PR tests were performed on 20 samples prepared by mixing montmorillonite, kaolinite, and quartz in different proportions. The PR method for the SSA determination of the soil samples showed high correlations with the two standard methods and with published data. These correlations show that the PR method is comparable to current standard methods. Additionally, two statistical analyses showed that the PR method yielded the same results as the other methods, and even more statistically similar results to the published values than either of the standard methods. The PR method offers advantages over current methods because of the uniform shape of the hemoglobin molecule and the presence of positively and negatively charged amino acids. This study has shown that the PR method is a new, inexpensive, and reliable method for the SSA measurement of soil.