Specific Surface Area by Colorimetry and Image Analysis

Marisol Salva Ramirez, Carlos Santamarina

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Specific surface area is more informative than grain size for fine-grained sediments where Ss > 1 m2/g. In fact, specific surface area plays a central role in engineering properties and processes in fine-grained soils, including pore size and bioactivity; fabric, plasticity, and rheology; hydraulic and electrical conductivity; compressibility and residual friction angle; and all forms of coupled processes. This research advanced a dye adsorption method using digital image colorimetry implemented with smartphone technology. In particular, this research adopted a water-based approach to reach internal surfaces in platy phyllosilicates, selected short dye molecules to reduce the range of potential molecular contact area, and developed a physics-based adsorption model to analyze the complete data set to minimize the uncertainty in specific surface area determinations. The study involved fine-grained soils with distinct mineralogy and specific surface area (from 1 to 600 m2/g) and various cationic dyes and a protein to explore the effect of molecular size, shape, and pH. Crystal violet emerged as a reliable dye for soil characterization. Time-dependent measurements confirmed second-order kinetics and highlight the importance of adsorption time.
Original languageEnglish (US)
Pages (from-to)20210026
JournalGeotechnical Testing Journal
Issue number1
StatePublished - Sep 21 2021

Bibliographical note

KAUST Repository Item: Exported on 2022-06-15
Acknowledgements: Support for this research was provided by the KAUST Endowment at King Abdullah University of Science and Technology.

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology


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