Stability in acidic solutions

The stability of the enzyme-polymer complex and its dissociation upon the variation of pH depends on the structural and other physico-chemical properties of CP and enzyme molecule. Thus, a Biocarb-T heteroreticular biosorbent (Fig. 26) is characterized by a stability of its complex with ot-amylase (under the condition of its stabilization) in acid solutions and a complete dissociation of the complex during isolation of the active enzyme at pH 7-8. 

Only the + 2 state of cobalt has thermodynamic stability in acid solution. The instability of Co3+ is referred to in Section 5.3. Only the + 3 states of Rh and Ir are stable in acid solution their +3/0 standard reduction potentials are quite positive, consistent with their nobility . In alkaline solutions the + 2 and + 3 states of the elements exist as insoluble hydroxides. 

CHEMICAL PROPERTIES stable under normal temperatures and pressures stable at room temperature in neutral and alkaline solution in the dark for more than fourteen days slightly less stability in acidic solutions sensitive to ultraviolet light photochemically reactive hazardous polymerization has not been reported may be oxidized to nitramine or reduced to the hydrazine or amine has shown resistance to hydrolysis FP (61 C, 14l.8°F) LFL/UFL (unknown) AT (unknown). 

With the increasing concentration of aluminum in the framework (with the Si/Al ratio decreasing to 1), the hydrophilic character of zeolites rises. The same relation exists between the number of exchangeable cations and the affinity for polar molecules. On the other hand, thermal stability, stability in acidic solutions, hydrophobic character of zeolites, and their affinity for nonpolar molecules increases with the decreasing aluminum concentration (increasing Si/Al ratio). 

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