Structural Change of Water with Solutes and Temperature up to 100 °C in Aqueous Solutions as Revealed by Attenuated Total Reflectance Infrared Spectroscopy

Abstract

The attenuated total reflectance infrared (ATR-IR) spectra of several aqueous solutions have been measured by using a newly developed heatable rod-type ATR cell. The OH stretching bands showed systematic change with increasing solute concentrations and these changes can be explained by four different OH components based on curve-fitting results. NaCl solutions show longer H-bond distance character, while carbonate solutions present shorter ones. The Na2CO3 1 M solution conserves this shorter H-bond nature up to 100 degrees C. On the other hand, the loose nature of NaCl solutions becomes less pronounced at higher temperatures because of the dissociation of pure water clusters. These in situ observations of water structures are generally in agreement with the expected nature of fluids within the earth.

ATR-IR spectroscopic study of L-lysine adsorption on amorphous silica

“…The logarithm of the signal intensity ratio − log(I/I 0 ) was called here "absorbance," and was used for the quantitative spectral analyses [23]. The ATR-IR spectra of lysine solutions include not only the contributions from the dissolved lysine but also a large contribution from the water; therefore, a spectrum of pure water was also measured and subtracted from the spectrum of each lysine solution (subtraction factor = 1).…”

“…It would be due to excess Na + (from NaOH) or Cl − (from HCl) ions added to adjust the pH of lysine solutions (up to about 0.34 mol/L), respectively. The influences of adding Na + and Cl − ions on the peak shapes of water in ATR-IR spectrum were examined by Masuda et al [23], and it was demonstrated that the peak height at 1630 cm −1 due to OH bending mode changes with increasing NaCl concentration. However, we selected the subtraction factor of unity to remove the fraction of water because the bands due to lysine structure, particularly the bands at 1733, 1559, 1521 and 1412 cm −1 are well separated from 1630 cm −1 , and the residual water band around 1630 cm −1 has little influence on the following analytical results.…”

Temperature imaging of sub-millimeter-thick water using a near-infrared camera

“…Various solutes such as ions, alcohol, and saccharide certainly affect the H-bonds and vibrations of water molecules [38]. Given a practical concentration of each solute, however, the absorption bands of water would be still dominant and their spectra would not be deformed much.…”

IR and Raman spectroscopic measurements of water at high temperatures and pressures

“…, 1996;Gorbaty and Bondarenko, 1999;Tassaing et al, 2002;Gorbaty et al, 2004;Zhang and Hu, 2004) ( , 1997;Ikushima et al, 1998;Kawamoto et al, 2004;Okada et al, 2005) (2003) (2000) (2002) Meer et al, (2005) nm OH 9 3 5 6 (Koga et al, 1998) OH (Frantz, 1998;Masuda et al, 2003;Nickolov et al, 2003;Li et al, 2004;Nickolov and Miller, 2005) (HDF Hydrothermally Derived Fracturing) HDF (Hirano et al, 2002) (Hirano et al, 2003) 900 C 2 5 GPa (2000) …”

“…(BX51, ( 2000;Tassaing et al, 2002;Masuda et al, 2003;Nickolov, 2003;Gorbaty, 2004) (100 C 400 C) Figure 5 100 C 400 C (Thompson, 1965…”