Baseline Studies of the Clay Minerals Society Source Clays: Colloid and Surface Phenomena

Abstract

The interface between the surfaces of clay minerals and other materials (aqueous solution, organic moieties, biomolecules, etc.) is of great importance to many geological, technological and biological processes. The examination of the structure and composition of mineral surfaces is advancing rapidly. However, the crystal structure of a mineral is only part of the information needed to understand the activity of the surface; we still do not fully understand the chemical and physical interactions at the surface or interface. One very powerful methodology for the study of surfaces and interfacial interactions is the determination of the thermodynamic properties of the surface. It became possible in the late 1980s to determine quantitatively the apolar and polar surface-tension components and parameters of liquids and solids (van Oss et al., 1988; van Oss, 1994), and the experimental techniques necessary for obtaining surface free-energy components of minerals, and particularly of colloid-sized minerals, are also a recent development (Costanzo eta!., 1990; van Oss et al., 1990, 1992; Giese et al., 1991).

Coating of silica sand with aluminosilicate clay

“…The values for smectite agree with previously reported data [34]. Different values of contact angles of kaolinite have been reported: 46.1 • was obtained with thin-layer wicking [34] and about 4 • was obtained with a goniometer method similar to ours [35]. Our values agree well with the previously reported goniometer value [35].…”

“…No trend in water and DIMcontact angle was obvious for kaolinite. Surface tension and free energy components for smectite and kaolinite (Table 6) were similar to those reported previously [34]. The effect of the polymer on the surface tension components (γ LW S , γ + S , and γ − S ) did not reveal a clear trend for any of the clay minerals.…”

Comparison of different methods to measure contact angles of soil colloids

“…As the sessile drop method requires a flat surface upon which a liquid drop can be placed, colloids are often deposited as a film onto a microscope slide or filter paper [6][7][8][9][10]. Smooth films have been made with synthetic colloids, such as Latex microspheres [11], mineral colloids, such as smectites and hematite [9,12], bacteria, such as Pseudomonas cepacia 3N3A, Arthrobacter sp., Escherichia coli [13,14], and viruses, such as hepatitis A [15]. Spherical, monodisperse particles, like microspheres are often used with the sessile drop method [11].…”

“…Spherical, monodisperse particles, like microspheres are often used with the sessile drop method [11]. Among soil colloids, smectites are particularly suitable for the sessile drop method, because these clays are swelling, and form a water impermeable surface [9]. If the colloidal film is porous, then the liquid drop will penetrate into the film, and as a consequence the contact angle changes with time [9,16].…”

Effect of Cycloaliphatic Amine on the Shale Inhibitive Properties of Water-Based Drilling Fluid

“…MCHA with a sequence of concentration was incorporated into 2 wt% Na-MMT dispersion. After reaching adsorption equilibrium, the dispersions were coated on the surface to glass slides following the procedures described by Wu [22]. The glass slides were left air dried.…”