Spectroscopic characterization of the structural and functional properties of natural organic matter fractions

Proton-binding study of standard and reference fulvic acids, humic acids, and natural organic matter

Organic Matter Characterization

Publisher Summary This chapter deals with humic substances and discusses its chemistry and reactions. Humic substances, major organic constituents of soils and sediments, are widely distributed over Earth's surface, occurring in almost all terrestrial and aquatic environments. Humic substances arise from the chemical and biological degradation of plant and animal residues and from synthetic activities of microorganisms. The products so formed tend to associate into complex chemical structures that are more stable than starting materials. Important characteristics of humic substances are their ability to form water-soluble and water-insoluble complexes with metal ions and hydrous oxides and to interact with clay minerals and organic compounds such as alkanes, fatty acids, dialkyl phthalates, and pesticides. The capacity of humic substances to adsorb water and plant nutrients was one of the first observations. Humic substances were thought to arise from the prolonged rotting of animal and plant bodies. The chapter also describes the synthesis of humic substances.

Chapter 1 Humic Substances: Chemistry and Reactions

The inability to determine metal species in soils hampers efforts to understand the mobility, bioavailability, and fate of contaminant metals in environmental systems, to assess health risks posed by them, and to develop methods to remediate metal contaminated sites. Fortunately, great strides have been made in the development of methods of species characterization and in their application to the analysis of particulates and mixtures of solid phases in physics, analytical chemistry, and materials science. This manuscript highlights a selection of the analytical methods available today offering the greatest promise, briefly describes the fundamental processes involved, examines their limitations, points to how they have been used in the environmental and geochemical literature, and offers some suggested research directions in the hope of stimulating further investigation into the application of these powerful tools to the problems outlined above.

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R. Riffaldi

Papers

Electron Spin Resonance Spectrometry of Humic Substances1