Abstract
The analysis of various models assumed to represent the influence of pH on heavy metals biosorption equilibrium is presented. It shows that all of them lead to the same mathematical expressions (e.g. the Langmuir or the Flory adsorption isotherm equations) when the pH effects are neglected. Even if considering the pH effects, some of them (competitive adsorption and ion-exchange models, for instance) still lead to analogical expressions for sorption isotherm equations. The accepted mechanism of biosorption may, however, influence strongly the differences between the initial and equilibrium states of biosorption system.
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Abbreviations
- M:
-
metal ion
- X:
-
binding site
- K a :
-
deprotonation constant
- N s :
-
concentration of binding sites
- q :
-
sorbed amount of metal
- n,π:
-
constants related to the metal binding reaction
- m :
-
mass of sorbent
- Δ:
-
difference between quantities in (12)–(14)
- x :
-
dimensionless concentration of metal ions in the bulk phase
- κA–κE:
-
constants depending on the considered model
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Rudzinski, W., Plazinski, W. How does mechanism of biosorption determine the differences between the initial and equilibrium adsorption states?. Adsorption 16, 351–357 (2010). https://doi.org/10.1007/s10450-010-9244-z
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DOI: https://doi.org/10.1007/s10450-010-9244-z