Neutron scattering quantification of unfrozen pore water in frozen mud

Research output: Contribution to journalJournal articlepeer-review

  • Will P. Gates
  • Nunes Bordallo, Heloisa
  • Abdelmalek Bouazza
  • Genaro Gonzalo Carnero-Guzman
  • Laurence P. Aldridge
  • Alice Klapproth
  • Gail N. Iles
  • Norman Booth
  • Richard A. Mole
  • Tilo Seydel
  • Dehong Yu
  • Nicolas R. de Souza

The Earth's polar regions are experiencing a greater frequency of freeze-thaw events throughout the polar summer, contributing to atmospheric methane and destabilising clay-rich sediments. Clays in soils tightly bind pore water and thus substantially modify freeze-thaw events. While temperatures of phase transitions for confined pore water may be precisely assessed using calorimetric or thermal analyses to -30 or -40 degrees C, neutron scattering directly probes how pores in clay minerals control ice formation and melting to lower temperatures. We apply elastic neutron scattering to accurately quantify the unfrozen water content of clay gels and unambiguously identify different pore-water environments by their freezing temperatures. Using this approach, we conclude that cryosuction controls water mobility in frozen soils in the absence of soluble salts to much lower temperatures than observed by other techniques. Dyanmics determined from neutron scattering indicates that water in clay gel pores thaws at much lower temperatures than currently considered, and thus pose potential risks for contaminant migration at sub freezing temperatures. The general poor strength of wet clays can significantly impact infrastructure in cold regions undergoing an increased frequency of freeze-thaw events.

Original languageEnglish
Article number111267
JournalMicroporous and Mesoporous Materials
Volume324
Number of pages7
ISSN1387-1811
DOIs
Publication statusPublished - 1 Sep 2021

    Research areas

  • Cyrosuction, Gel pores, Capillary pores, Clays, Neutron scattering, SOIL, DYNAMICS, DESORPTION, GELS, NMR, ICE

ID: 277226240