Organic buffering capacity

Phosphoric Acid. This acid is the primary acidulant in cola beverages. Phosphoric acid is stronger than most organic acids and weaker than other mineral acids. The dibasic properties of phosphoric acid provide minor buffering capacity in the beverage. Food-grade phosphoric acid is commercially available in concentrations of 75%, 80%, and 85% and is one of the most economical acidulants. 

Fruit and vegetable juices packed with 21-26 in. of vacuum and stored in uncoated aluminum cans caused severe corrosion as shown in Table III. The corrosion rate brought about by the juices depends more on the nature of the organic acid present and the buffering capacity of the juice than on the total titratable acidity (11). The use of coated aluminum containers considerably minimized corrosion problems. Product control under extended storage conditions may be achieved by using specific chemical additives. However, more work is needed in this area before final conclusions can be reached. 

Microbial activity, which is often stimulated during bioremediation projects, can alter the external pH. For instance, the anaerobic degradation of chlorinated compounds produces organic acids and HC1 and the pH may drop to acidic values if the soil has a low buffering capacity. In this case, control of the external pH will be required in order to maintain biodegradation activity at... 

You carry out a reaction in an organic solvent. The reaction is catalysed by a lipase immobilised by adsorption on a porous support. The reaction virtually stops long before equilibrium is reached and you suspect that this can be due to the formation of an acidic reaction product. What can you do to increase the buffering capacity of the system ... 

In areas where the geology is dominated by granite, lakes have less buffering capacity and are much more susceptible to the impacts of acid rain. Fish and aquatic organisms differ in their ability to adapt to acidic conditions. The natural pH of lakes is approximately 8.0. The pH of poorly buffered lakes is between 6.5 and 7.0. The effects of pH on different aquatic organisms are summarized in Table 18.1. 

Acid-Base. The pH of natural waters is determined primarily by the carbonate equilibria. However, organisms may produce amounts of organic matter or ammonia sufficient to influence the pH and buffer capacity of the waters. It would be of interest to determine titration curves of high organic, high color, low alkalinity waters leached from some marshes. It is possible that these waters contain sufficient amounts of organic acids to be significant. 

The presence of acidic functional groups, mostly carboxyl and phenolic OH groups, in the molecular structure of soil HS renders them major players in the acid-base buffering capacity of soils and in the fate, bioavailability, and physico-chemical behavior of macro- and micronutrients, toxic metal ions, and several xenobiotic organic compounds in soil (Ritchie and Perdue, 2003 Senesi and Loffredo, 2005). Consequently, the effects of amendment on the acid-base properties of soil HAs and FAs is a subject of considerable interest. 

Microbial-driven mineralization of organic matter can also contribute to acidification of the rhizosphere (Badalucco and Nannipieri, 2007). It should be noted that pH variations in the rhizosphere depend also on the soil s buffering capacity... 

Many factors control whether a given water body will become acidified as a result of a given deposition regime. In addition to the deposition rate and the lake residence or turnover time, these include the ratio of water surface area to watershed area, the composition of the lake bottom, the residence time of incident precipitation en route through the watershed, and the buffering capacity of the watershed. The presence of organic material can also be important. 

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