Ultrasound velocity measurements in liquid media

Abstract

This review is a survey of the authors` scientific investigations in the field of ultrasound velocity measurements in electrolyte solutions and various liquid systems. Measurements were performed with a specially designed ultrasonic-laser interferometer and a pulse-echo system. The main molecular acoustic interferometric experiments were provided in aqueous solutions of nine lanthanide nitrates and six sulphates within the frequency range of 3÷200 MHz. The rear earth elements from lanthanum (57) to lutecium (71) are the ideal group for investigation of the ion-ion interaction as well as influence of ion field on the solvent structure. Data of ultrasound velocity dispersion at different temperatures and concentrations are interpreted as being due to the process of association of lanthanide (III) ions and ligands and formation of inner sphere complexes [LnNO₃]_aq²⁺ and [LnSO₄]_aq⁺. Kinetic parameters for the formation of inner sphere complexes have been determined. Non monotonic variation of the hydration number was obtained for lanthanide nitrate solutions across the series. Measurements in the synovial and cerebrospinal fluids were provided with the aim of disease diagnostics, in blood – for coagulation studies. Water-glycol mixtures were proposed as reference media, acrylamide polymerization - as a phantom for blood clotting. Some investigations were provided for the application in the control of technological processes.