Non-exchangeable acidity

Kissel, D. E., E. P. Gentzsch, and G. W. Thomas. 1971. Hydrolysis of non-exchangeable acidity in soils during salt extractions of exchangeable acidity. Soil Sci. 111 293-297. 

If soil pH is increased (H" " in solution decreased), the equilibrium shifts to the right some non-exchangeable acidity released. If soil pH is... 

Non-exchangeable acidity. Bound and that is not displaced, or is extremely slowly displaced, into solution by a concentrated neutral salt, usually l.O M KCl. This form is associated with weak acid groups on humus, organically complexed Al, and Al-hydroxy cations strongly retained at mineral surfaces. 

Non-exchangeable acidity = Extractable acidity - Exchange acidity. 

Catalyst Co content (mmol) Non exchanged acid sites (mmol) Reaction rate (mmol/min) Cyclohexane conversion (%) Adipic acid yield (%)... 

In this work a novel five-step leaching scheme for HM has been developed addressing exchangeable, acid soluble (carbonate), easily reducible (bound to Mn oxides), easily oxidizable (bound to humic and fulvic acids), and moderately reducible (bound to amorphous Ee oxides) fractions extractable by 0.05 M Ca(N03), 0.43 M CH3COOH, 0.1 M NH,OH-HCl (non-acidified), 0.1 M K/,03 (pH 11), and 0.1 M (NH4),C,04 (pH 3), respectively. The sequence of extractants was chosen according to recent studies on the selectivity of leachants toward dissolved phases of soils. 

Fig. 4. Helical structure of collagen, typical amino acid sequence within a collagen strand, and exchangeable versus non-exchangeable hydrogen atoms in an individual leucine molecule (Gly - glycine. Pro - Proline, Leu - leucine. Hyp - hydroxyproline.

Dissociation of the neutral acid in water necessitates modifications for air-sea exchange in the model, which is based on Henry s law. Other possible pathways, e.g. sea spray, are neglected. Henry s law is restricted to concentrations of physically solved, non dissociated substances. Since only the non-dissociated acid is volatile, it is important to correct the air-water partition coefficient as to reflect the relative proportions of volatile and non-volatile components. The corrected parameter is the effective Henry s law coefficient, which is related to the Henry s law coefficient as a function of pH (modified Henderson-Hasselbalch equation) ... 

North Eastern USA Morgan, Modified Morgan, Mehlioh 1 and Mehlioh 3 All are acidic and could extract some non-exchange-able K. Ammonium based reagents extract more K than FI or Na based ones... 

In axenic cultures, some EMF can get access to non-exchangeable potassium and calcium reserves in micas such as phlogopite and vermicu-lite (Paris et al., 1995a, b, 1996). Application of limiting amounts of potassium and magnesium in the nutrient media increased the release of potassium from phlogopite, and seemed to be accompanied by increased exudation of oxalic acid by the EMF (Paris et al., 1995a, 1996). Exposure... 

When the anion exchange membrane has weakly basic anion exchange groups, the membrane is equilibrated with acid solution, e.g., 1.0 N hydrochloric acid solution, for protonation and washed with methanol to remove non-ion-exchanged acid from the membrane. Then the membrane is equilibrated with a given amount of standardized sodium hydroxide solution and the remaining standardized sodium hydroxide is determined by titration. 

In the case of an acid soil, non-exchangeable (constitutional) basic groups adsorb hydrogen ions, which can thus support the formation of hydrogen bonds... 

---