Aluminum mobilization

The adsorption of aluminum onto clay surfaces can be a significant factor in controlling aluminum mobility in the environment, and these adsorption reactions, measured in one study at pH 3.0-4.1, have been observed to be very rapid (Walker et al. 1988). However, clays may act either as a sink or a source for soluble aluminum depending on the degree of aluminum saturation on the clay surface (Walker et al. 1988). 

Campbell PGC, Hansen HJ, Dubreuil B, et al. 1992. Geochemistry of Quebec north shore salmon rivers during snowmelt organic acid pulse and aluminum mobilization. Can J Fish Aquat Sci 49 1938-1952. 

B. S. Hemingway, Gibbs free energies of formation for bayerite, nordstrandite, Al(OH)2+, and Al(OH)2 aluminum mobility, and formation of bauxites and laterites, Adv. Phys. Geochem. 2 285(1982). The mechanistic basis of the GLO Step Rule is discussed in Chap. 6 of W. Stumm, Chemistry of the Solid-Water Interface, Wiley, New York, 1992. See also Chap. 5 in W. Stumm and J. J. Morgan, op. cit.12... 

Ague J. J. (2000b) Aluminum mobility during metamorphism of carbonate rocks. Geol. Soc. Am. Abstr. Progr. 32, A-296. 

K/T boundary. Aluminum mobilization by sulfuric acid in K/T soils may have formed alunite (KA13 (S04)(0H)6), basaluminite (AJUSO OH o I O), or other sulfate-containing A1 hydroxide minerals, but once soil pH values returned to 5-6 these phases altered to gibbsite and kaolinite thus losing all traces of sulfate. 

Yokel RA, Datta AK and Jackson EG (1991) Evaluation of potential aluminum chelators in vitro by aluminum solubilization ability, aluminum mobilization from transferrin and the octanol/ aqueous distribution of the chelators and their complexes with aluminum. J Pharmacol Exp Ther 257 100-106. 

Box 12-1 Aluminum Mobilization from Minerals by Acid Rain... 

Henriksen A., Wathne B. M., Rpgeberg E. J. S., Norton S. A., and Brakke D. F. (1988b) The role of stream substrates in aluminum mobility and acid neutralizatiorL Water Res. 22, 1069-1073. 

To illustrate the principles discussed above, two case examples are examined to determine the controlling mechanisms of silicate dissolution, and the final outcome. In the first case study, organic acids preferentially mobilize silica in a microbially active oil-contaminated aquifer, whereas the second study shows a transition between enhanced aluminum mobility at acidic pH and enhanced silica mobility at neutral pH in a peat bog. 

The main objective of this chapter is to review experimental work on organic acids and mineral dissolution under diagenetic conditions. Consequently, emphasis is placed on experiments conducted at elevated temperatures (70-100°C). The primary focus is on the effects of carboxylic acids on feldspar solubility and dissolution kinetics as they relate to potential aluminum mobility and creation of secondary porosity. 

---