Acid neutralization capacity

Acidification the decrease of acid neutralizing capacity in water or base saturation in soil caused by natural or anthropogenic processes. 

Acid deposition is of greatest concern wherever there are large amounts ol lossil fuel combustion upwind of an area. Eastern North America, large areas of Europe, and eastern Asia all receive acidic deposition. Acidic deposition is especially a concern when poorly buffered soils, with little acid-neutralizing capacity, are impacted. In North America, large areas of eastern Canada, the Adirondack Mountains of upstate New York, and sections of New England all are considered acid sensitive areas, where resistant bedrocks and thin soils prevent significant neutralization of acidity. 

Soil solution equilibrium. Soil solution equilibriumis based on the quantification of acid-neutralizing capacity, ANC, which has been defined as ... 

This equation equals the net input of (sea-salt corrected) base cations minus a critical leaching of acid-neutralizing capacity. 

One important application of acid-base titrations is the determination of the alkalinity of various kinds of samples. It is an especially important measurement for the proper treatment of municipal water and wastewater. Alkalinity of a water sample is defined as its acid-neutralizing capacity. It is determined by titrating the water sample with standard acid until a particular pH is achieved. The alkalinity value... 

Base neutralizing capacity = -Acid neutralizing capacity... 

ANC of Humus. The acid neutralizing capacity of a solution containing humus is primarily due to the sum of concentrations of dissociated humus and of free OH ... 

Acid deposition can cause acidification of soils and waters. Acidification can be defined as a reduction of the acid-neutralizing capacity of soils or waters. The acidneutralizing capacity is also known as alkalinity (AUc) and indicates the sensitivity of a water system toward acidification. It can be expressed as [9] ... 

Acid neutralizing capacity (ANC) - ANC is a consideration in selecting an antacid. It varies for commercial antacid preparations and is expressed as mEq/mL. Milliequivalents of ANC is defined by the mEq of hydrochloride required to keep an antacid suspension at pH 3.5 for 10 minutes in vitro. An antacid must neutralize at least 5 mEq/dose. Also, any ingredient must contribute at least 25% of the total ANC of a given product to be considered an antacid. 

Based on a study comparing N-Viro soil physical properties with those of mineral soils, the physical characteristics of N-Viro soils suggest that chemical characteristics (such as high initial pH, acid neutralizing capacity, and high soluble salt content), rather than physical attributes, are likely to limit the use of these materials as soil substitutes. 

Antacids are basic compounds that neutralise acid in gastric lumen, have no effect on gastric acid secretion. They are quantitatively compared in terms of their acid neutralizing capacity (ANC), which is defined as the quantity of 1 N HCl (in MEq) that can be brought to pH 3.5 in 15 minutes by a unit dose of antacid preparation. An ideal antacid should be potent in neutralizing acid, inexpensive, not absorbed from GIT and contain negligible amounts of sodium, should be sufficiently palatable to be readily tolerated with repeated dosage and should be free of side effects. An ideal antacid is yet to be developed. 

It is a potent antacid with rapid acid neutralizing capacity, but on long term use, it can cause hypercalcemia, hypercalciuria and formation of calcium stones in the kidney. 

Johnson, C. A., Brandenberger, S. Baccini, P. 1995. Acid neutralizing capacity of municipal... 

The base should be a strong buffer. A comparison of the titration of 0.2 N KOH and 0.2 N K2C03 adjusted to pH 12 shows that it is easier to exceed the acid-neutralizing capacity of the KOH compared with the buffered solution of K2C03 (see Figure 4). 

The neutralization capacity of a tumbling drum equates to fines production per unit flow, which depends on the energy expended per unit flow to tumble the stone, and on the hardness of the stone. Energy expended per unit flow varies with the shroud diameter, KD, and the efficiency of the water wheel, as discussed above. Stone hardness is determined by the Los Angeles abrasion rating, A, a road stone test. Experience with tumbling drums indicates an acidity neutralization capacity of 3... 

Figure 8. Effect of baseline acid-neutralizing capacity (ANC) and episodic conditions in Adirondack lakes, a, Relationship between baseline ANC and the springtime depression in ANC (baseline ANC—minimum ANC) for 11 lakes sampled in 1986 and 1987. b, The relative contributions of base cations (Cb) and nitrate (N03 ) to the springtime ANC depressions in Adirondack lakes. Lakes at intermediate ANC values undergo the largest springtime depressions in ANC. Lakes with lower baseline ANC are affected more by N03 pulses, and lakes with higher baseline ANC are affected more by base-cation dilution. Solid lines represent best-fit relationships. (Redrawn with permission from reference 126. Copyright 1990 American Geophysical Union.)...

Figure 10. Temporal patterns in lake-water N03, acid-neutralizing capacity (ANC), base cations (Ca + + Mg2+ + Na+ + K+), S042, and inorganic monomeric aluminum (Al ) at Constable Pond, a long-term monitoring site in the Adirondack Mountains. Trend lines are shown for variables with significant trends (p < 0.10 in seasonal Kendall tau test). Seasonal pattern is typical of Adirondack lakes, with seasonal minima in ANC coincident with seasonal maxima in NOf and Ah. Many Adirondack lakes exhibited upward trends in N03 in the 1980s the primary increase was in episodic N03 concentrations.

Figure 16. Outflow chemistry from two snowmelt seasons (1986 and 1987) at Emerald Lake, a high-elevation lake in the Sierra Nevada Mountains of California. Maximum N03 concentrations are coincident with ANC minima during the early stages of snowmelt in 1986 and with a rain-on-snow event in 1987. Nitrate episodes are smaller in magnitude than at sites in the eastern United States, hut western lakes may he more susceptible to episodic acidification because they have a lower baseline acid-neutralizing capacity than most eastern lakes. (Reproduced with permission from reference 180. Copyright 1991 American Geophysical Union.)...

Alkalinity refers to the acid neutralization capacity of the solution in moles of protons, generally referred to as "equivalents", per unit volume. For our purposes, it can be divided into the alkalinity associated with the carbonic acid system, carbonate alkalinity (Ac), and the alkalinity associated with all other solution components. 

---