Acids, adsorption organic

Schofield RK, Samson HR (1954) Flocculation of kaolinite due to the attraction of opposite charged crystal faces. Discuss Faraday Soc 18 135-145 Schofield RK, Samson HR (1953) The defiocculation of kaolinite suspensions and the accompanying change-over from positive to negative chloride adsorption. Clay Miner BuU 2 45-51 Schulten HR (2001) Models of humic structures association of humic acids and organic matter in soils and water. In Qapp CE et al. Humic substances and chemical contaminants. Soil Science Society of America, Madison, Wl, pp 73-88... 

The acidity of organic ligands is enhanced by coordination with the oxide surface, i.e. the surface promotes deprotonation of the functional groups (COOH or OH). Such ligands, therefore, adsorb on the surface at a pH 2-3 units lower than that at which complexation with Fe in solution would occur (Kummert and Stumm, 1980). An example of this is the deprotonation of the alcoholic OH group of tartaric acid upon adsorption on the goethite surface (Cornell and Schindler, 1980). The appropriate reaction for the acid in water is. 

Zullig, J. J., and J. W. Morse, Interaction of organic acids with carbonate mineral surfaces in seawater and related solutions. I. Fatty acid adsorption , Geochim. Cosmochim. Acta, 52, 1667-1678 (1988). 

Large adsorbates, such as bi-isonicotinic acid, may bind to a surface at several sites which are sufficiently far apart not to interact strongly in a direct way. This kind of system is by necessity large and complex, and few detailed studies have been reported on such systems. Various structural aspects of bi-isonicotinic acid adsorption on rutile and anatase TiC>2 surfaces have been presented in several recent studies [68, 77, 78]. Bi-isonicotinic acid adsorption on TiC>2 surfaces is not only taken as a problem of direct interest to the photoelectrochemical applications, but also serves as a model system for surface science investigations of phenomena connected to the adsorption of large organic adsorbates on metal oxide surfaces. 

Carter P.W. (1978) Adsorption of amino-acid containing organic matter by calcite and quartz. Geochim. Cosmochim. Acta 42, 1239-1242. 

P. A. W. van Hees, S. I. Vinogradoff, A. C. Edwards, D. L. Godbold, and D. L. Jones, Low molecular weight organic acid adsorption in forest soils effects on soil solution concentrations and biodegradation rates, Soil Biol. Biochem. 35, 1015-1026 (2003). 

Oelkers E. H. and Schott J. (1998) Does organic acid adsorption affect alkali-feldspar dissolution rates Chem. Geol. 151(1-4), 235-245. 

Studies of organic acid adsorption on Fe oxides indicate that the maximum surface density of chemisorbed anions on these minerals is about 2 molecules/100 A. ... 

Adsorption is carried out either with the so-called batch method or by filtration through a column. It is possible to conduct fractional desorption in many cases, for example by using acids or organic solvents. Certain substances in water can also be concentrated by means of ion exchange resins. By using an appropriate ion exchanger, e.g. cation or anion exchangers of certain types, it is possible not only to separate cations... 

Silica surfaces are the chief source of activity in columns for SFC and, even though many of the columns are well deactivated, the residual silanol sites can lead to tailing or adsorption of analytes. The low surface area of capillary columns is responsible for much higher levels of inertness than their packed counterparts based on silica particles. Capillary columns have been used successfully in the analysis of active compounds, including isocyanates, acid halides, organic acids, amines, peroxides, azo compounds, and many others. The low temperatures required for elution make analysis of active and labile compounds viable. 

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