The Opposite Effect of Metal Ions on Short-/Long-Range Water Structure: A Multiple Characterization Study.
Inorganic electrolyte solutions are very important in our society as they dominate many biochemical and geochemical processes. Herein, an in-depth study was performed to illustrate the ion-induced effect on water structure by coupling NMR, viscometer, Raman and Molecular Dynamic (MD) simulations. The NMR coefficient (BNMR) and diffusion coefficient (D) from NMR, and viscosity coefficient (Bvis) from a viscometer all proved that dissolved metal ions are capable of enhancing the association degree of adjacent water molecules, and the impact on water structure decreased in the order of Cr(3+) > Fe(3+) > Cu(2+) > Zn(2+). This regularity was further evidenced by Raman analysis; however, the deconvoluted Raman spectrum indicated the decrease in high association water with salt concentration and the increase in low association water before 200 mmol·L(-1). By virtue of MD simulations, the opposite changing manner proved to be the result of the opposite effect on short-/long-range water structure induced by metal ions. Our results may help to explain specific protein denaturation induced by metal ions.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. makai@tju.edu.cn.
Kai
K
Ma
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. zhaolin@tju.edu.cn.
Lin
L
Zhao
D004058:Diffusion; D007477:Ions / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D013059:Spectrum Analysis, Raman; D014783:Viscosity; D014867:Water / Q000737:chemistry*
D007477:Ions; D008670:Metals; D014867:Water
long-range effect; metal ion; molecular dynamics simulations; spectrometer