Study of Microalgal Peloids Prepared with Laias Mineral-Medicinal Water for Use in Pelotherapy

Peloids are thermotherapeutic agents used in several spas and thermal centers; their behavior depends on their physical properties, and these determine their forms of application. This work focuses on the study of the thermophysical properties of the mixtures of a clay, Laias mineral-medicinal water, and microalgae. The properties studied are density, specific heat, thermal conductivity, thermal diffusivity, and apparent viscosity as a function of the concentration of the water, at atmospheric pressure and a temperature of 308.15 K. The density of the mixtures was determined by a pycnometric method. The specific heat was determined using a CALVET microcalorimeter. A Decagon KD2 Pro conductivity meter was used to measure thermal conductivity. Thermal diffusivity was calculated from the data obtained on thermal conductivity, density and specific heat. Apparent viscosity measurements were carried out using a Schott rotational viscometer (Cole-Parmer, Vernon Hills, IL, USA). Results showed that the ternary mixtures with the highest percentage of mineral-medicinal water present the best thermotherapeutic behavior (95% water; Density: 1005 Kg/m3; Specific heat: 4037 J/kg K; Thermal conductivity: 0.592 W/m K; Thermal diffusivity: 0.146 × 10−6 m2/s; Apparent viscosity: 0.002 Pa s). The objective of this research is to contribute new knowledge in relation to microalgal peloid characteristics and their quality criteria concerned with therapeutic and wellness purposes, and how this could help in choosing the most suitable type of application for each mixture.