Spectroscopic property of frozen clay-water system
-- Measurement of Infrared spectra by FTIR --  

M. MIZOGUCHI*, and Philip F. Low. 
Mie Univ., Japan; and Purdue Univ.

FTIR is often used to study the structure  of  absorbed  water  on 
clay particles.  A  new  infrared  spectroscopic  method  was 
developed   to determine  ice content in frozen samples.  The method
was  based on  an  equation  which  was  derived  in  this  study  
relating absorbance of frozen solution to the volume fraction of
ice.  Infrared  spectra  of  0.12 mm thick frozen samples were
obtained  at sub-zero temperature over the range of frequencies
between 1800 and 4000 cm-1 with a FTIR spectrometer.  It was found
around the frequency of 2700 cm-1 that transmittance decreased
sensitively with decreasing temperature.  The volume fraction of
ice in NaCl solution, calculated from the equation at the frequency
of 2700 cm-1, agreed well with the values predicted from a phase
diagram of the system H2O-NaCl.  The freezing point of the
clay-water system, determined by the absorbance at the frequency of
2700 cm-1, was lower than that of water and decreased as the system
contained salt.  The present method is promising to determine ice
content and freezing point depression in frozen samples.

M. Mizoguchi, FAX:(81)592-31-6590,
E-mail:mizo@mips.cc.mie-u.ac.jp