Toxic metals chelates

Chemical reaction path calculations (Alpers and Nordstrom, 1999 Bethke, 1996) have only seen limited use as applied to fluid-mineral interactions in the human body (e.g., Davis et al., 1992). The potential further applications in this realm are intriguing, both for understanding chemical reactions between body fluids and earth materials, and in understanding potential changes in body fluid chemistry in response to physiological processes and therapeutic treatments such as toxic metal chelation therapy. 

The clinical use of chelation is to transform the toxic metal complex with, say, an enzyme into a toxic metal complex with the administered chelating agent. Subsequently we want the enzyme to be reactivated and the toxic metal chelate complex to be excreted from the body in either the urine or the feces. When we use a chelating agent to treat metal intoxication, we transform the coordination sphere of the toxic metal ion and form a new complex with very different properties from those of the complex from which it was formed. One result of complexing a toxic metal ion with the therapeutically useful chelating agents is a considerable decrease in the... 

Malakul, P., Srinivasan, K., and Wang, H., Metal toxicity reduction in naphthalene biodegradation by use of metal-chelating adsorbents, Appl Environ Microbiol, 64 (11), 4610-4613, 1998. 

As shown in Fig. 1 biosorption comprises a variety of processes including ion exchange, chelation, adsorption, and diffusion through cell walls and membranes all of which are dependent on the species used, the biomass origin and, and solution chemistry (Gavrilescu 2004). Biosorption is a fast and reversible process for removing toxic metal ions from solution. 

Arsenic uptake in rabbit intestine is inhibited by phosphate, casein, and various metal-chelating agents (USEPA 1980). Mice and rabbits are significantly protected against sodium arsenite intoxication by (V-(2,3-dimercaptopropyl)phthalamidic acid (Stine et al. 1984). Conversely, the toxic effects of arsenite are potentiated by excess dithiols, cadmium, and lead, as evidenced by reduced food efficiency and disrupted blood chemistry in rodents (Pershagen and Vahter 1979). 

Numerous commercial dyes are metal chelate complexes. These metals form pollutants which must be eliminated. One of the strongest points in favour of electrochemical reduction/removal of metal ions and metal complexes - the metal ions and weakly complexed ions form the toxic species - and of the metals from the metal-complex dye is that they are eliminated from the solution into the most favorable form as pure metal, either as films or powders. Polyvalent metals and metalloids can be transferred by reduction or oxidation treatment to one valency, or regenerated to the state before use, e.g. Ti(III)/Ti(IV), Sn(II)/Sn(IV), Ce(III)/Ce(IV), Cr(III)/Cr(VI), and can be recycled to the chemical process. Finally, they can be changed to a valence state better suited for separation, for instance, for accumulation on ion exchangers, etc. Parallel to the... 

Toxie and biologically resistant materials will require special consideration for their treatment. You will need to adjust the nutrient stream to aeeommodate the bacteria in the system and aid in the hydrolysis of the eompounds or even wash or chelate the toxic metals out of the way. In one waste stream where nitroalcohols were being treated, the system required 42 days of detention in order to provide sufficient dilution and residence time to allow speeialized enzymes to develop in the bacterial population. 

Combination with penicillamine is contraindicated as penicillamine is a metal chelator. However penicillamine can be used to treat gold toxicity. N-acetylcysteine can also increase the excretion of gold. 

Chelation/Electrodeposition of Toxic Metals from Soils... 

Chemical interactions are those in which one chemical combines with another to become more or less toxic. For example, the chelating agent EDTA combines with toxic metals such as lead and decreases its toxicity (antagonism). 

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