Zeta Potential

Zeta potential refers to the charge potential surrounding a large molecule or colloid particle. Zeta potential is measured at the boundary between what is moving in a solution with the particle and the rest of the solution. Colloidal reaction dynamics have demonstrated that nanocolloidal or microcluster spherical minerals have unique bonding properties. They are hydrophilic, bind and release ions (adsorption, desorption), and alter solvation parameters of water or dispersed fluids. As the spherical mineral sets up a binding potential and ionic particles are introduced, the silicate mineral reaches an adsorption value due to its electronegativity, which is defined by a measurable zeta potential (measured in mV). Electronegativity refers to the tendency to attract electrons. The addition of

an increase in the concentration of anions added to the colloidal particle suspension compresses the double layer around the silicate mineral driving more ions toward the surface of the colloid. At some saturation level the anions that have been added to the colloid become the controlling ions. Adsorption takes place to a degree which is represented by an increase in the electronegative zeta-potential (a 0.1 mM anionic solution = -57 mV). Further addition of a higher concentration of anions increases the zeta potential to its maximum (a 0.35 mM anionic solution = -70 mV) and forms a monolayer. When mineral colloids of uniform size and spherical shape are well dispersed, and when natural bulk-stress is not excessive, "fluid" suspensions of 65-80% or higher are often possible (Riddick 1968). Ions binding to the silicate get intermingled with water and silica gels often look fluid or opaque because of water clinging to them.

Advanced techniques in colloidal and cluster chemistry have evolved over the past three decades further defining regions on silicates and other minerals that identify the presence of structured water arrangements around ions and in conjunction to the surface of the mineral. X-ray diffraction, NMR, laser and mass spectroscopy now predict and identify these complexes. Advanced technologies provide a close up view as to the stable mineral-water-ion complexes forming at mineral interfaces. Silicates, zeolites and other metal water interfaces have been analyzed for the appearance of water cages that are observed at the mineral interface. Semi stable hydrogen bonds between water clathraces are essentially the same as formed in ordinary ice. Although ice does not contain any chambers large enough for occupancy by molecules other than those of helium or hydrogen, some water arrangements form chambers large enough for slightly larger elements including another water molecule or a chlorine atom. The dodecahedron arrangement is common and consists of 46 water molecules (Pauling 1961). Some water/mineral cages are revealing fairly stable complexes. These form at the surface of silicate minerals.

Modern methods have enhanced the understanding of how and why colloidal mineral suspensions in certain size ranges behave the way they do. These complexes (water clathrates) were also observed and discussed by Linus Pauling and Szent Gyorgyi in biological systems. Ionic groups on proteins also tend to layer or structure water forming cagelike arrangements (lattices) between protein chains. In these systems it was revealed that reducing equivalents in the form of hydride ions or atomic hydrogen could be transferred across "water bridges" between biological molecules.