Minerals organic complexes

FigoFe 9. DTA patterns of mineral-organic complexes from A, B, and C horizons of volcanic ash soils of increasing age. 

Vanadium is found in about 65 different minerals among which are carnotite, roscoelite, vanadinite, and patronite, important sources of the metal. Vanadium is also found in phosphate rock and certain iron ores, and is present in some crude oils in the form of organic complexes. It is also found in small percentages in meteorites. 

Certain organic compounds, especially polyphenols, stimulate mobilization of clay by neutralizing positive charges at the edges of clay minerals. As iron-saturated organic complexes are insoluble, this process might be of little importance in Fe-rich Luvisols (particularly common in the subtropics). 

Mortland MM, Shaobai S, Boyd SA (1986) Clay-organic complexes as adsorbents for phenol and chlorophenols. Clays Clay Miner 34 581-595... 

The regulation of biogeochemical cycles by microbial populations is of most direct importance in the cycling of N, S, P, and C. Most of the ecosystem pool of these elements resides as organic forms in forest floor and mineral soil compartments. These organic complexes are subjected to microbial transformations, which regulate nitrate, sulfate and phosphate ions dynamics and availability. In turn, this influences indirectly... 

The distribution of the major elements (Ca, Mg, Na, K,. ..) in soils is well known to be governed by ion-exchange processes (1). The behaviour of transition elements such as Co, Ni, Cd, Cu, etc. in natural systems (soils, sediments) often results from a combination of different effects such as precipitation, sorption in oxides, exchange in clay minerals and complexation with organic... 

In addition to stabilizing organic products by reaction with metal-exchanged clays, as indicated above, aluminosilicate minerals may enable the preparation of metal organic complexes that cannot be formed in solution. Thus a complex of Cu(II) with rubeanic acid (dithiooxamide) could be prepared by soaking Cu montmorillonite in an acetone solution of rubeanic acid (93). The intercalated complex was monomeric, aligned with Its molecular plane parallel to the interlamellar surfaces, and had a metal ligand ratio of 1 2 despite the tetradentate nature of the rubeanic acid. 

Mordand MM (1970) Clay-organic complexes and interactions. Adv Agron 22 75-117 Mordamd MM (1986) Mechanism of adsorption of nonhumic organic species by clays. In Huang PM, Schnitzer M (eds) Interaction of soil minerals with natural organics and microbes. Soil Sci Soc Amer, Madison, Wisconsin, pp 59-76... 

Sedimentary carbonate-fluor-apatite Cas(P04,003)3 is not luminescent under X-rays, and under UV lamp excitation it is characterized by broad structureless bands which are very similar to those encountered in many sedimentary minerals. It was concluded that this luminescence is due to different kinds of water-organic complexes (Tarashchan 1978). For this reason the luminescence properties of the sedimentary apatites is much less informative compared to magmatic apatite and attracted not much attention. 

Brookhaven National Laboratory s (BNL s) biochemical recovery of radionuclides and heavy metals is a patented biochemical recovery process for the removal of metals and radionuclides from contaminated minerals, soil, and waste sites. In this process, citric acid, a naturally occurring organic complexing agent, is used to extract metals and radionuclides from solid wastes by the formation of water-soluble, metal-citrate complexes. The complex-rich extract is then subjected to microbiological biodegradation that removes most of the extracted heavy metals. 

The modern investigations of trace elements in coals were pioneered by Goldschmidt, who developed the technique of quantitative chemical analysis by optical emission spectroscopy and applied it to coal ash. In these earliest works, Goldschmidt (31) was concerned with the chemical combinations of the trace elements in coals. In addition to identifying trace elements in inorganic combinations with the minerals in coal, he postulated the presence of metal organic complexes and attributed the observed concentrations of vanadium, molybdenum, and nickel to the presence of such complexes in coal. 

Tomb cz, E. (2003). Effect of environmental relevant organic complexants on the surface charge and the interaction of clay mineral and metal oxide particles. In Role of Interfaces in Environmental Protection, Barany, S., ed., Kluwer, Dordrecht, 397-424. 

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