Dissolved organic carbon adsorption

Jardine, P. M., N. L. Weber, and J. F. McCarthy. 1989. Mechanisms of dissolved organic carbon adsorption on soil. Soil Science Society of America Journal 53 1378—1385. 

Both organic and inorganic ligands such as Cl and dissolved organic carbon (fulvie acid and carboxylic acids) decrease metal adsorption. In the arid soils with higher pH, folic acids increase the solubility of metals such as Cu and Zn. The interaction between the transition of heavy metals and silicate surfaces was reviewed by McBride (1991). 

Adsorption isotherm of (Aldrich) humic acid (HM) on 8-AI203 as a function of pH. Extent of adsorption was determined both by measurements of light absorption at 254 and 436 nm, respectively and by measurements of dissolved organic carbon (DOC) of the residual HM in solution (original concentration = 25 mg per liter). 

Only 10% of the dissolved organic carbon in seawater has been characterized on a molecular level. About 5 to 23% of this DOC can be isolated from seawater by adsorption onto a nonionic macroporous resin fiallowed by elution with an alkaline solution. 

Suba, J.D. and Essington, M.E. Adsorption of fluometuron and norflurazon effect of tillage and dissolved organic carbon. Soil Sci, 164(3) 145-155, 1999. 

All water sources may contain natural organic matter, but concentrations (usually measured as dissolved organic carbon, DOC) differ from 0.2 to more than 10 mg L l. NOM is a direct quality problem due to its color and odor, but more important are indirect problems, such as the formation of organic disinfection by-products (DBPs, e. g. M -halomethanes (THMs) due to chlorination), support of bacterial regrowth in the distribution system, disturbances of treatment efficiency in particle separation, elevated requirements for coagulants and oxidants or reductions in the removal of trace organics during adsorption and oxidation, etc. 

Grafe, M Eick, M.J. and Grossl, P.R. (2001) Adsorption of arsenate (V) and arsenite (III) on goethite in the presence and absence of dissolved organic carbon. Soil Science Society of America Journal, 65(6), 1680-87. 

A. Adsorption of Dissolved Organic Carbon and Dissolved Organic Nitrogen in Mineral Soil Horizons 53... 

Baham, J., and Sposito, G. J. (1994). Adsorption of dissolved organic carbon extracted from sewage sludge on montmorillonite and kaolinite in the presence of metal ions. J. Environ. Qual. 23,147-153. 

Crum, R.H., Murphy, E.M. and Keller, C.K. (1996) A non-adsorptive method for the isolation and fractionation of natural dissolved organic carbon. Water Res., 30, 1304-1311. 

After filtration, samples for reactive Hg (Hg-R) and total dissolved Hg (Hg-T) were acidified with 0.5% HC1.47 BrCl is also often used to preserve samples intended for Hg-T determination. The acidification of samples to be used for Hg-R determination was not recommended by Parker and Bloom,85 especially those with high levels of dissolved organic carbon (DOC). DOC may coagulate after acidification of the solution, with concomitant adsorption and precipitation of Hg-R. Labile Hg (Hg-R) appears to be relatively stable (days to weeks) in filtered, unpreserved samples. 

Cappelli, F., P.D. Goulden, J. Lawrence, and DJ. MacGregor. 1978. Determination of the adsorption efficiency of the organics carbon adsorbable standard method by dissolved organic carbon analysis. J. Environ. Sci. Health A 13 167-176. 

David, M.B. and Zech, W., Adsorption of dissolved organic carbon and sulfate by acid forest soils in the Fichtelgebirge, FRG, Z. Pflanzenemaehr. Bodenkd., 153, 379, 1990. 

In a recent review of technological alternatives for NOM removal, Jacangelo et al. [558] presented field data that illustrate wide variability in adsorption capacities of activated carbon in a single location (e.g., exhaustion periods between 41 and 182 days). They concluded that these results are evidence of the site-specific nature of [dissolved organic carbon] removal by [activated carbon] and that the concerns regarding reliability of treatment practices to meet the new [regulations] have a sound basis. Clearly, much fundamental work remains to be done to understand fully the complex nature of these adsorbent/adsorbate interactions and thus be able to optimize both the physical and the chemical accessibility of the carbon surface to natural organic matter. 

Leenheer and Huffman (1976) designed a hydrophobic classification of dissolved organic carbon using resin adsorption as a means of fractionation. The procedure is based on adsorption chromatography onto XAD resins. Those organic substances that adsorb onto the resins with pH adjustment (low pH for acids and neutral pH for bases) are termed hydrophobic those organic substances that do not absorb are hydrophilic. Fulvic and humic acids are classified as hydrophobic substances. This classification procedure makes it possible to measure indirectly the amount of humic substances in water. A more detailed explanation of this procedure is presented by Leenheer (1981). 

Leenheer and Huffman (1976) have developed a fractionation procedure for aquatic organic solutes called dissolved organic carbon (DOC) fractionation. The procedure for the analytical DOC fractionation is shown in Figure 3. Hydrophobic solutes are first removed from water by adsorption on Am-berlite XAD-8 resin, hydrophilic bases in the effluent are removed by cation-exchange resins, and hydrophilic acids in the effluent are removed by anion-exchange resins. Aquatic humic substances occur primarily in the... 

---