| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a Dep. of Plant and Soil Sciences, Oklahoma State Univ., Stillwater, OK 74078 USA
b Dep. of Soil, Water and Climate, Univ. of Minnesota, St. Paul, MN 55108 USA
haz{at}agr.okstate.edu
The dissolution rates of most primary and secondary minerals are promoted by the presence of proton- and complex-forming ligands. Effects on the rates of dissolution of hornblende by naturally occurring organic acids at concentrations commonly encountered in soil solutions and surface waters was studied in a pH 4.0, 0.01 M HOAc–LiOAc buffer. Crushed hornblende samples were purified by magnetic and density separation, followed by an initial period of weathering in a buffered aqueous solution for 39 d. After the initial weathering the rate of dissolution was measured at different concentrations of citric, oxalic, polygalacturonic, tannic, and fulvic acids at pH 4.0 for another 32 d in a batch-type reactor. Although nearly linear kinetics were observed for the release of Si, the release of Al, Fe, and Mg decreased with time. The dissolution was nonstoichiometric during the study period with preferential release of Al, Fe, and Mg relative to Si. All ligands studied were found to accelerate the dissolution process and the rates increased with solution concentrations of organic acids. The reaction orders with respect to dissolved organic C were generally low, ranging from near zero to 0.37 for different organic acids. At a concentration of 2.5 mM of dissolved C the relative effectiveness of these ligands on promoting dissolution was oxalic > citric > tannic > polygalacturonic > fulvic acid. The strengths of organic acids to promote dissolution is related to the quantity of phenolic and carboxylic functional groups present on the organic compounds, and it is related to the strength of the metal–ligand complex formed in solution or on the mineral surface.
Abbreviations: DCP, direct current plasma emission spectroscopy • EDTA, ethylenediamine tetra-acetic acid • FA, fulvic acid • ICP, inductively coupled plasma emission spectroscopy
This article has been cited by other articles:
|
|
 |
|
  A. Neaman, J. Chorover, and S. L. Brantley Effects of organic ligands on granite dissolution in batch experiments at pH 6 Am J Sci, June 1, 2006; 306(6): 451 - 473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Proust, J. Caillaud, and C. Fontaine CLAY MINERALS IN EARLY AMPHIBOLE WEATHERING: TRI- TO DIOCTAHEDRAL SEQUENCE AS A FUNCTION OF CRYSTALLIZATION SITES IN THE AMPHIBOLE Clays and Clay Minerals, June 1, 2006; 54(3): 351 - 362. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Sutter, L. R. Hossner, and D. W. Ming Dissolution Kinetics of Iron-, Manganese-, and Copper-Containing Synthetic Hydroxyapatites Soil Sci. Soc. Am. J., March 1, 2005; 69(2): 362 - 370. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Neaman, J. Chorover, and S. L. Brantley Implications of the evolution of organic acid moieties for basalt weathering over geological time Am J Sci, February 1, 2005; 305(2): 147 - 185. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Mikutta, M. Kleber, K. Kaiser, and R. Jahn Review: Organic Matter Removal from Soils using Hydrogen Peroxide, Sodium Hypochlorite, and Disodium Peroxodisulfate Soil Sci. Soc. Am. J., January 1, 2005; 69(1): 120 - 135. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Hamer, R. C. Graham, C. Amrhein, and K. N. Bozhilov Dissolution of Ripidolite (Mg, Fe-Chlorite) in Organic and Inorganic Acid Solutions Soil Sci. Soc. Am. J., March 1, 2003; 67(2): 654 - 661. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
