Abstract
The two main motivations for studying equations which describe adsorption of phosphate are to understand the processes involved, and to summarize many results by a few numbers. If more than one hypothesis about the process is tenable, appropriate statistical procedures should be used both to choose between them and to obtain the best summary of the results with a given equation. Equations most likely to be successful in describing adsorption are those in which the affinity for adsorption decreases as the amount of adsorption increases. This effect is inherent in the process of phosphate adsorption and occurs because specific adsorption of anions increases the negative charge on the adsorbing surface. It is included in the complex equations of Bowden, and in simpler fashion in the Freundlich equation. Because the simpler equation can only approximately describe the true situation, a perfect fit over a wide range of concentrations should not be expected. Equations for which the affinity for adsorption is constant — such as the Langmuir equation — are not consistent with our knowledge of the adsorption process. This difficulty is not avoided by the multi‐surface Langmuir equations: such equations may also be difficult to justify on statistical grounds.
| Original language | English |
|---|---|
| Pages (from-to) | 447-462 |
| Number of pages | 16 |
| Journal | Journal of Soil Science |
| Volume | 29 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Jan 1978 |
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THE DESCRIPTION OF PHOSPHATE ADSORPTION CURVES. / BARROW, N. J.
In: Journal of Soil Science, Vol. 29, No. 4, 01.01.1978, p. 447-462.Research output: Contribution to journal › Article
TY - JOUR
T1 - THE DESCRIPTION OF PHOSPHATE ADSORPTION CURVES
AU - BARROW, N. J.
PY - 1978/1/1
Y1 - 1978/1/1
N2 - The two main motivations for studying equations which describe adsorption of phosphate are to understand the processes involved, and to summarize many results by a few numbers. If more than one hypothesis about the process is tenable, appropriate statistical procedures should be used both to choose between them and to obtain the best summary of the results with a given equation. Equations most likely to be successful in describing adsorption are those in which the affinity for adsorption decreases as the amount of adsorption increases. This effect is inherent in the process of phosphate adsorption and occurs because specific adsorption of anions increases the negative charge on the adsorbing surface. It is included in the complex equations of Bowden, and in simpler fashion in the Freundlich equation. Because the simpler equation can only approximately describe the true situation, a perfect fit over a wide range of concentrations should not be expected. Equations for which the affinity for adsorption is constant — such as the Langmuir equation — are not consistent with our knowledge of the adsorption process. This difficulty is not avoided by the multi‐surface Langmuir equations: such equations may also be difficult to justify on statistical grounds.
AB - The two main motivations for studying equations which describe adsorption of phosphate are to understand the processes involved, and to summarize many results by a few numbers. If more than one hypothesis about the process is tenable, appropriate statistical procedures should be used both to choose between them and to obtain the best summary of the results with a given equation. Equations most likely to be successful in describing adsorption are those in which the affinity for adsorption decreases as the amount of adsorption increases. This effect is inherent in the process of phosphate adsorption and occurs because specific adsorption of anions increases the negative charge on the adsorbing surface. It is included in the complex equations of Bowden, and in simpler fashion in the Freundlich equation. Because the simpler equation can only approximately describe the true situation, a perfect fit over a wide range of concentrations should not be expected. Equations for which the affinity for adsorption is constant — such as the Langmuir equation — are not consistent with our knowledge of the adsorption process. This difficulty is not avoided by the multi‐surface Langmuir equations: such equations may also be difficult to justify on statistical grounds.
UR - http://www.scopus.com/inward/record.url?scp=84984500228&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2389.1978.tb00794.x
DO - 10.1111/j.1365-2389.1978.tb00794.x
M3 - Article
VL - 29
SP - 447
EP - 462
JO - Journal of Soil Science
JF - Journal of Soil Science
SN - 0022-4588
IS - 4
ER -