The adsorption of polysaccharides onto mineral surfaces: an acid/base interaction

http://www.columbia.edu/~ps24/PDFs/Adsorption_and_conformationMay2005.pdf

Adsorption and conformation of carboxymethyl cellulose at solid-liquid interfaces using spectroscopic, AFM and allied techniques.

In soil and water, ferrihydrite frequently forms in the presence of dissolved organic matter. This disturbs crystal growth and gives rise to coprecipitation of ferrihydrite and organic matter. To compare the chemical fractionation of organic matter during coprecipitation with the fractionation involved in adsorption onto pristine ferrihydrite surfaces we prepared ferrihydrite-organic matter associations by adsorption and coprecipitation using (i) a forest-floor extract or (ii) a sulfonated lignin. The reaction products were studied by (13)C CPMAS NMR, FTIR, and analysis of hydrolyzable neutral polysaccharides. Relative to the original forest-floor extract, the ferrihydrite-associated organic matter was enriched in polysaccharides, especially when adsorption took place. Moreover, mannose and glucose were bound preferentially to ferrihydrite, while fucose, arabinose, xylose, and galactose accumulated in the supernatant. This fractionation of sugar monomers was more pronounced during coprecipitation and led to an enhanced ratio of (galactose + mannose)/(arabinose + xylose). Experiments with lignin revealed that the ferrihydrite-associated material was enriched in its aromatic components but had a lower ratio of phenolic C to aromatic C than the original lignin. A compositional difference between the adsorbed and coprecipitated lignin is obvious from a higher contribution of methoxy C in the coprecipitated material. Coprecipitated organic matter may thus differ in amount and composition from adsorbed organic matter.

Fractionation of organic matter due to reaction with ferrihydrite: coprecipitation versus adsorption.

Pure water is an essential requirement for the survival of human beings. To meet the requirements of potable, industrial and agricultural water, the immediate need is to treat waste water, particularly the sewage sludges and slimes from the municipal and industrial effluents respectively. These effluents are highly undesirable and unsafe. The removal of contaminants from waste water is a must before they can be reused. The removal of contaminants from these effluents involves the process of flocculation and coagulation. The purpose of the present article is to clarify and explain the processes in details along with the materials involved in the processes. This will be essential for the present day life.

http://inet.vidyasagar.ac.in:8080/jspui/bitstream/123456789/713/2/JPS10art9.pdf

L.J Warren

Papers

Selective flocculation of ultrafine iron ore. 1. Mechanism of adsorption of starch onto hematite

Selective flocculation of ultrafine iron ore 2. Mechanism of selective flocculation

Quantitative thermogravimetric analysis of haematite, goethite and kaolinite in Western Australian iron ores