Bicarbonate d'ammonium

Résumé

Le bicarbonate d'ammonium (formule NH4HCO3) est un sel bicarbonate de l'ammonium. C'est un produit irritant pour la peau, les yeux et le système respiratoire. Il est utilisé dans l'industrie agroalimentaire comme poudre à lever en association ou non avec d'autres sels comme le bicarbonate de soude. Propriétés

Apparence : à température ambiante, c'est une poudre blanche.
Solubilité dans l'eau : le bicarbonate d'ammonium est très soluble dans l'eau, qu'il rend alcaline (basique, à pH élevé). Sa dissolution est endothermique, c'est-à-dire qu'elle absorbe de la chaleur et que la température de la solution baisse en absence d'apport externe de chaleur.
Il porte le numéro E503(ii) comme additif alimentaire.

Voir aussi

Bicarbonate de sodium (bicarbonate de soude)
Carbonate d'ammonium

Références Ammonium Catégorie:Composé de l'ammonium Catégorie:Agent levant Catégorie:Régulateur alimentaire de pH

Source officielle

https://fr.wikipedia.org/wiki/Bicarbonate_d'ammonium

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, ,

“Switchable water” is an aqueous solution containing a water‐soluble amine additive that exhibits CO2‐switchable properties, such as large changes in ionic strength, by forming an ammonium bicarbonate salt. Switchable water has been used to reversibly “salt‐out” organic compounds from water. This study explores the salting out of several compounds in switchable water when CO2 is present and also explores the solubility of small molecules in switchable water, compared to pure water, when CO2 is absent. The results show that organic compounds are generally more soluble in switchable water than pure water in the absence of CO2, but less soluble in the presence of 1 atm CO2. Exceptions include carboxylic acids and phenols which, presumably due to their acidity, are more soluble in switchable water than in pure water, even when CO2 is applied. Kirkwood–Buff solvation theory was applied to gain insights into the effects of the amine additive on the aqueous solubility of caffeine. Furthermore, the switchable properties of the additives allow for the preparation of switchable aqueous two‐phase systems.

2018

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BUCHLORAC: Program for predicting the bicarbonate requirement for anaerobic bioremediation of chlorinated solvents

David Andrew Barry, Clare Robinson

2008

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pH control for enhanced reductive bioremediation of chlorinated solvent source zones

David Andrew Barry, Clare Robinson

Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils’ natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron- accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil’s buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron(III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user- specified operating conditions.

Elsevier2009

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