Peloids prepared with three mineral-medicinal waters from spas in Granada. Their suitability for use in pelotherapy

Three peloids were studied, prepared with three mineral-medicinal water (MMW) from the spas at Alicun (sulphate, rich in magnesium and calcium, highly mineralized), Zujar (sulphate, rich in sodium chloride, highly mineralized) and Graena (sulphate, rich in magnesium and calcium, highly mineralized) (province of Granada, Spain) and matured for three months, in order to determine their properties and suitability for use in pelotherapy. Their solid phase was prepared by mixing kaolin and bentonite (9:1, w:w). In the peloids the following was studied: composition of interstitial liquid, granulometry, physicochemical properties (specific surface area-SSA-, cation exchange capacity -CEC- and exchangable bases), crystallinity index of the minerals, thermal behavior and ultramicroscopic fabric using scanning electron microscopy (SEM) and image analysis (IA). A modification of the ionic concentration of the interstitial liquid was observed with regard to the initial MMW, namely, an increase in the concentration of Na+ and K+, and a decrease in Ca2+ and Mg2+, due to exchange between the exchangable cations of the solid phase and the ions of the MMW. Increases in the proportion of fraction <2 mu m, SSA and CEC were also observed. The crystallinity index of the kaolinite decreased after three months' maturation, as compared to the initial mineral sample. The fabric developed during maturation was porous and reticulated and the fabric parameters were related to the thermal properties of the peloid. The properties of the three peloids studied make them potentially suitable for use in pelotherapy.