Aluminum complexes phosphates

Within the pH range of 5-6, aluminum complexes with phosphate and is removed from solution. 

Using the HSAB principle, one can rationalize the corrosion inhibition of iron and aluminum by phosphate in which iron phosphate and aluminum phosphate are produced. Ferric and Al3+ are hard acids, and they react with phosphate, a hard inhibitor and give corrosion protection. Corrosion inhibition of Cu2+ and Zn2+ by amines can be rationalized by the formation of amine complexes of Cu2+ and Zn2+, and this is in accord with the principle that Cu2+ and Zn2+ are borderline acids reacting with amines which belong to borderline inhibitors. Corrosion protection of copper (soft acid) by mercapto-benzothiazole (soft inhibitor) is also in keeping with the HSAB principle. 

Potassium silicate, available commercially in colloidal ratios, is used nowadays for specialized liquid detergents. It is available in weight ratios of 1 1.5 to 1 2.5. Silicates soften water by the formation of precipitates that can be easily rinsed away. Silicates are corrosion inhibitors of stainless steel and aluminum that can be caused by synthetic detergents and complex phosphates [3]. 

Tnteraction of aluminum and phosphate has long been a problem of interest to soil scientists and water chemists. Many different precipitates have been prepared by mixing solutions of aluminum salts and phosphate (4, 5, 6, 17). Some of these precipitates are crystalline, but many others are amorphous. Some have definite stoichiometric compositions, but many others do not. Some are dissolved in IN HCl almost instantaneously, but others can be dissolved only after prolonged heating. On the other hand, the formation of soluble complexes of aluminum and phosphate has been suggested (3y 8,14). 

Write the formula for the phosphate salt (if the complex ion is a cation) or the aluminum salt (if the complex ion is an anion) for the ions in Question 5. 

Modification of the top electrode may also be achieved. This was done by adding a small amount of surfactant, such as an ether phosphate or an ether sulfate, to the spin-coal solution of the luminescent polymer [89[. The lipophobic ether chains segregate at the surface of the (predominantly) hydrocarbon polymer, becoming available for complexation with the aluminum cathode which is deposited on top. Thus, the dipole in the surfactant points away from the electrode and lowers its work function to improve the injection of electrons. 

Humus and organic matter can have a dramatic effect on analytical results as shown in the work by Gerke [16]. Metal complexes, particularly aluminum and iron, were found to complex with phosphate. These complexes, which accounted for 50-80% of the phosphate present, were not detectable by standard phosphate analytical procedures. When developing a soil analytical method, it is essential that the method be either applicable to soils of all organic matter contents or that variations of the procedure applicable to soils of differing organic matter be developed [16-19],... 

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