Interactions of Hydrazine and of Hydrazine Derivatives with Soil Constituents and with Soils.
Annual rept. 1 Dec 80-1 Dec 81,
BIRMINGHAM UNIV (ENGLAND) DEPT OF CHEMISTRY
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Studies have demonstrated that at high pH, in the solution phase, colloids catalyse hydrazine degradation. This catalysis is particuarly dependent upon the exchangeable metal cations held by the colloids, and exceeds that of equivalent solutions of the metal cations alone. Hydrazines can be strongly or weakly sorbed by soil colloids in essentially unchanged forms, or can be irreversibly chemisorbed. Reversible ion-exchange is the main mechanism of hydrazineclay interaction at low pH. Insoluble iron-and aluminium-hydrous oxides form on the surfaces of suitably exchanged clays at high pH, and these bind large amounts of hydrazines by strong hydrogen-bonding forces and by hydrazination of cationic species. Such binding partially destabilises hydrazine towards thermal degradation. Hydrazines interact with humic colloids by chemisorption, by ion-exchange, and by hydrazination of strongly polarizing cations. The reactivity of humates is determined by their exchangeable metal cations, and by the pH, which both affect their penetrability and solubility. Clay colloids and goethite react strongly with hydrazines from the vapour phase. Results show that the hydrazines can compete well with water for interaction sites. Preliminary results from whole soilhydrazine experiments show the large capacity of different soil types for interaction with hydrazines. A copperII-treated, aerated clay soil is highly effective in degrading applied hydrazine.
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