Metals removal from body

The removal of metal ions from waste aqueous solutions is of importance to many countries of the world both environmentally and for water re-use. The application of low-cost sorbents including carbonacceous materials, agricultural products and waste by-products has been investigated [1], Several researchers employing wide variety techniques have attempted removal of metal ions from contaminated water bodies. Majorities of these are adsorption on various surfaces. In recent years, agricultured by products have been widely studied for metal removal from water. These include peat [2], pine bark [3], banana peat [4], peanut shells [5], sawdust [6] and leaves [7]. 

Polyelectrolytes such as the ion exchange plastics form an interesting group of materials because of their ability to interact with water solutions. They have been used in medical applications involving the removal of heavy metal ions from the human body. They can be used to interact with external electric fields and change their physical properties drastically as is illustrated by the fact that some electrically active liquid crystals are polyelectrolytes of low molecular weight. 

Assuming no chemical reaction, what will happen if we place a piece of metal at one temperature into water at another temperature The metal will gain energy from or lose energy to the water until their temperatures are the same. Whichever was at the higher temperature initially will lose energy to the other. In the absence of any energy loss to any other body, the quantity of heat removed from one will be added to the other. We can use this fact to measure specific heats of substances, or to predict the final temperatures to which such combinations will arrive. The principle involved may be summarized in the equation ... 

Not all agents can be readily metabolized. The toxic metals lead and mercury are elements that cannot be degraded but must still be removed from the body. Another important mechanism of detoxification is the attachment or binding of another compound to a toxic chemical to make it easier for the kidney to filter the compound out of the blood and excrete it in the urine. A primary purpose of the kidney is to screen the blood for waste products and concentrate them in the urine for excretion, as occurs, for example, with mercury. Caffeine is excreted in the urine at approximately the same concentration as the blood because the kidney cannot concentrate caffeine. Vitamins, however, are readily concentrated and excess quickly eliminated in the urine. 

Fe(Hedta), Na2Fe(edta) Zn2+, Mn2+, Mg2 edta complexes see Chapter 62.1) (iv) removal of poisoning or radioactive metal ions from the body (Cd2+ NaCa(edta) Pb2+ Na3Ca(dtpa) see Chapter 62.2). Complexones have been used in the form of " Tc complexes to obtain scintigraphic imaging of human organs in diagnostic nuclear medicine (see Chapter 65). 

Ignoring for the present ionization and contraction of the lattice, the structure of cesium chloride may be considered similar to that of cesium metal, but with the cesium atoms removed from the body centers and chloride ions inserted. In the diffraction pattern for cesium chloride, the 100 reflections, 111 reflections, and other reflections absent from the pattern for cesium metal are present but are weak. Wave interference similar to that occuring for cesium metal must occur, but here interference is not complete. The planes of chloride ions are not as strong reflectors or scatterers as the planes of cesium ions (the scattering power of an atom rises sharply with atomic number). Thus, interference in cesium... 

Metallothionein The metallothioneins are generated in response to high concentrations of certain metal ions. They bind these ions extremely efficiently such that they are rendered harmless and can be removed from the body. 

Biosorption promises to fulfill the requirements, which are competitive, effective, and economically viable. Efforts have been made to use different forms of inexpensive plant materials for the removal of toxic metals from the aqueous media. Some typical biosorbents explored so far in removing toxic metal ions from water bodies have been listed in Table 3.1. 

A number of the transition metals are essential trace elements for living organisms, so that one medical application of transition metal compounds is in the treatment of deficiency diseases. Particular examples are provided by preparations containing iron to treat anaemia and the use of dietary supplements containing cobalt in the form of vitamin B 2, shown as its cyanide derivative in 1.5. The reverse of this type of treatment involves the removal of excess metal ions from the body using com-... 

Refining of crude fats and oils involves a series of steps for the removal of impurities from the glycerides to make the product suitable for human consumption and improve product shelf life. The impurities are fatty acids, phosphatides, metal ions, color bodies, oxidation products, solid paricles, and volatiles that include objectionable odors. Crude coconut oil is refined by any of the following methods (1) chemical refining (batch or continuous) and (2) physical refining. The comparative performance of both methods is summarized in Figure 4. 

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