Sorption of Anhydrous Ammonia by Dry Clay Systems

Abstract

NH3 sorption and/or retention over the pressure range of 0 to 100 ml. of mercury by dry bentonite, halloysite, and synthetic gibbsite was investigated using a manometric technique employing equilibrium measurements in a special sorption apparatus. Chemisorbed NH3 is believed to be that which has gained a proton and undergone exchange reactions with the exchangeable cations and that which has reacted with the weakly dissociated hydroxyl groups of the lattice edges. The differential influence of saturating cations is believed to be due, at least in part, to the differences in degrees of hydration of these ions. Possible mechanisms of sorption are proposed. There were no differences in amounts of NH3 sorbed and chemisorbed by Ca‐bentonite adjusted to pH 8, 9, and 10. This lack of influence is explained on the basis of the pH range involved and the mechanisms of sorption. The failure of synthetic gibbsite, Al(OH)3, to chemisorb NH3 is explained by the basic nature of the mineral.

Nitrogen Isotopic Fractionation in Ammonia during Adsorption on Silicate Surfaces

“…The effect of water was not clearly visible in the total adsorption in our experiments because the water content was relatively small. The difference observed between montmorillonite and saponite is probably due to the difference in the amount and species of exchangeable cations as well as water in the interlayer space, considering that these are responsible for the formation ratio of ammonium ions. , …”

“…The difference observed between montmorillonite and saponite is probably due to the difference in the amount and species of exchangeable cations as well as water in the interlayer space, considering that these are responsible for the formation ratio of ammonium ions. 14,24 Nitrogen isotopic fractionation by adsorption is important in various fields. For example, it poses a potential risk for isotopic analysis using chromatographic separations.…”

Reactions of Ammonia With Soil. I

“…Mortland et al (1963) also interpreted infra-red spectra and heats of adsorption of NH, on cation-saturated montmorillonite partly in terms of this reaction. James and Harward (1964) and Brown and Bartholomew (1962), discussing adsorption isotherms of NH, on clays, also suggested sorption mechanisms involving water of hydration. Other suggested roton sources (in addition to exchangeable protons or protons provided gy dissociation of water bound to A13+ or Fe3+) are hydroxyl groups in organic matter and SiOH groups in clay minerals and the so-called 'amorphous' fraction of soils (see Fig.…”

Retenção e nitrificação da amônia em solos do município de Piracicaba

“…Embora teoricamente haja uma certa distinção entre retenção física e química da am�nia no solo, BROWN & BARTHOLOMEW (1962) afirmam não haver método que separe a amônia retida física mente daquela quimicamente retida.…”