Organo-mineral complex adsorption

Three specific areas can be identified to serve as foci for expanding the research on this material (i) The nature of the organic components interactions need to be ascertained. Do the lipids (whose chemistry is dominated by aliphatic components) and humic (whose chemistry is dominated by aromatic, carboxyl, and carbohydrate components) actually exist as distinct domains in organo-mineral complexes (ii) What is the effect of the mineral surface on adsorbed macromolecule conformation How does conformation impact the adsorption of additional NOM components (iii) Finally, a better understanding of the interfacial chemistry of these organo-mineral composites needs to be developed in order to understand the fate of many organic contaminants introduced into natural systems. 

Effects of organic ligands on the adsorption of trace elements onto metal oxides and organo-mineral complexes... 

Trace elements in cationic and anionic forms show a different adsorption capacity on metal oxides, organic matter, and organo mineral complexes. The isotherms of Cu, Zn, and As absorbed at pH 4.0 onto POL (extracted from ohve oil mill waste waters), a Fe (OH) -POL complex, and ferrihydrite are shown in Fig. 4. 

The amounts of As adsorbed on the Fe (OH) -POL complex were not only much greater than on POL (Fig. 4B) but were also much higher than those of Cu (Fig. 4A) and Zn adsorbed on the organo-mineral complex. More As was sorbed on ferrihydrite than on the Fe(OH) -POL complex (Fig. 4B), evidently because the organic molecules partially prevented As adsorption (as discussed below). On ferrihydrite, the difference between the amounts of As and those of Cu and Zn adsorbed was still much greater than on Fe(OH) -POL and POL (data not shown). 

The metabolic activities of soil microorganisms are also significantly altered by surface adsorption on clays although very little is known yet about the interactions that take place between the indigenous population and soil surfaces. Soil phosphatases are also intimately associated with the soil organo-mineral complex and their adsorption on clay surfaces usually but not invariablyreduces enzyme activities. The mechanisms of adsorption of proteins, including enzymes, on clays and the effects on their properties have recently been reviewed . ... 

Cowan CT, White D (1962) Adsorption by organo-clay complexes. Clays Clay Miner 9 459-467... 

Clay minerals, oxides, and humic substances are the major natural subsurface adsorbents of contaminants. Under natural conditions, when humic substances are present, humate-mineral complexes are formed with surface properties different from those of their constituents. Natural clays may serve also as a basic material for engineering novel organo-clay products with an increased adsorption capacity, which can be used for various reclamation purposes. 

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