Surface Characteristics of Mineral Fibers

As expected, most mineral fibers have a very small heat of wetting when compared to organic fibers, even those that are considered to have low heats of wetting. This tells much about the properties of fibers and what the surface characteristics are on a molecular scale. A large literature has been published dealing with the adsorption isotherms of fibers. These measurements can reveal much about the types of adsorption occurring at the surface of a fiber. 

Of importance in the case of mineral fibers is the adsorption of substances from a solution in which they are submerged. Willard Gibbs published an isotherm for the adsorption of dissolved substances onto a solid substrate. It was shown that a substance which lowered the surface tension of a liquid at the solid-liquid interface would usually be more concentrated on the surface of a submerged solid than in the body of the solution. These are usually referred to as surface-active agents. On the other hand, substances that raise the surface tension of a liquid in which they are dissolved will be negatively adsorbed at a surface. The concentration of these salts will be greater in the body of the solution than at an interface. In company reports, I have called these salts body active salts. Many electrolytes will raise the surface tension of water. 

One conceived application of [NaCa(P03)3] was as filter media to filter beverages, such as wine or beer. Here, it is imperative that the fiber remove 

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