/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

Study and Interpretation of the Chemical Characteristics of Natural Water

https://cyberleninka.org/article/n/1018032.pdf

Polymer nanotechnology: Nanocomposites

FTIR techniques in clay mineral studies

Halloysite clay minerals are ubiquitous in soils and weathered rocks where they occur in a variety of particle shapes and hydration states. Diversity also characterizes their chemical composition, cation exchange capacity and potassium selectivity. This review summarizes the extensive but scattered literature on halloysite, from its natural occurrence, through its crystal structure, chemical and morphological diversity, to its reactivity toward organic compounds, ions and salts, involving the various methods of differentiating halloysite from kaolinite. No unique test seems to be ideal to distinguish these 1:1 clay minerals, especially in soils. The occurrence of 2:1 phyllosilicate contaminants appears, so far, to provide the best explanation for the high charge and potassium selectivity of halloysite. Yet, hydration properties of the mineral probably play a major role in ion sorption. Clear trends seem to relate particle morphology and structural Fe. However, future work is required to understand the possible mechanisms linking chemical, morphological, hydration and charge properties of halloysite.

Halloysite clay minerals — a review

The behavior of colloid systems is governed primarily by their large interfacial area. The interface is defined as the boundary region between the adjoining bulk phases that comprise the colloid system. When one of the phases is a gas or a vapor, the term surface is commonly used for the boundary region. The foundation for thermodynamic treatment of surfaces was established in the last century by Gibbs, who published a considerable contribution to the field in 1878. His work still forms the basis of modern thermodynamics (Gibbs, 1928).

Physical Chemistry of Surfaces

Structure and surface acidity of clay minerals introduction to organo-clay complexes and interactions interactions of vermiculites with organic compounds organophilicity and hydrophobicity of organo-clays adsorption of organic cations on clays - experimental results and modelling nuclear magnetic resonance spectroscopy thermal analysis of organo-clay complexes IR-spectroscopy and thermo-IR-spectroscopy in the study of the fine structure of organo-clay complexes staining of clay minerals and visible-absorption spectroscopy of dye-dye complexes clay catalysis in reactions of organic matter organo-materials and organo-clay interactions and the origin of life on Earth.

Organo-Clay Complexes and Interactions

Geochemistry of colloid systems

The role of charcoal on DTA curves of organo-clay complexes: an overview

Clay minerals, hydrated oxides, and hydroxides, mainly of Si, Al, Fe, and Mn, and some organic macromolecules are responsible for most wettability properties of geologic systems that constitute the sedimentary cycle. They are the soil components that exert the dominant influence on chemical and physical properties of a soil, and a detailed examination of the nature of their wettability by water is essential for a complete understanding of a soil’s potential with respect to agricultural and engineering applications.(1–3) The clay minerals, which generally constitute the greatest part of the colloid fraction in these systems, are named after the term used by sedimentologists and soil scientists for the fraction of particles having a very small size, with an equivalent diameter smaller than 2 μm, the “clay fraction.” Although most clay minerals occur as particles too small to be resolved by the ordinary microscope, x-ray diffraction analysis shows that most of them, even in their finest size fraction, are composed of crystalline particles and that the number of crystalline minerals likely to be found is limited. Furthermore, a wide distribution of particle size is frequently present and certain clay deposits contain well-defined crystalline particles with diameter greater than 2 μm.

Shmuel Yariv

Papers

Physical Chemistry of Surfaces

Organo-Clay Complexes and Interactions

Geochemistry of colloid systems

The role of charcoal on DTA curves of organo-clay complexes: an overview

Wettability of Clay Minerals