Physicochemical fate of sulfate in soils

Journal Article · Thu Jan 01 04:00:00 EST 1987 · J. Air Pollut. Control Assoc.; (United States)

DOI:https://doi.org/10.1080/08940630.1987.10466197· OSTI ID:7095424

Tabatabai, M A

Sulfur occurs in soils in organic and inorganic forms, with the inorganic S accounting for <5 percent of the total S in most soils from humid and semihumid regions. Sulfate in soils may occur as water-soluble salts, adsorbed by soil colloids, or as insoluble forms. Considerable seasonal fluctuations in the concentration of soluble SO/sub 4//sup 2 -/ in surface soils occur as a result of interaction of seasonal conditions on the mineralization of organic S, leaching, and uptake by plants. Soils vary widely in their capacity to adsorb SO/sub 4//sup 2 -/. Sulfate adsorption is readily reversible and the amount SO/sub 4//sup 2 -/ adsorbed is concentration and temperature dependent. The capacity of soil to adsorb SO/sub 4//sup 2 -/ depends upon clay content, nature of clay minerals, pH, associated cation, and the amount of hydrous Al and Fe oxides. The mechanisms of SO/sub 4//sup 2 -/ retention by soils involve coordination with hydrous oxides, exchange on edges of silicate clays, incorporation in mineral structures, and molecular adsorption. For acid soils, SO/sub 4//sup 2 -/ adsorption essentially involves the chemistry of Fe and Al. Sulfate adsorption increases as the pH decreases below zero point of charge. Several forms of insoluble SO/sub 4//sup 2 -/ are likely to occur in soils, including BaSO/sub 4/, SrSO/sub 4/, SO/sub 4//sup 2 -/ associated with CaCO/sub 3/, and basic Fe and Al sulfates.

• Research Organization: Iowa State Univ., Ames
• OSTI ID: 7095424
• Journal Information: J. Air Pollut. Control Assoc.; (United States), Journal Name: J. Air Pollut. Control Assoc.; (United States) Vol. 37:1; ISSN JPCAA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring &amp; Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ADSORPTION
CHEMISTRY
DISSOLUTION
LEACHING
MINERALIZATION
OXYGEN COMPOUNDS
SEASONAL VARIATIONS
SEPARATION PROCESSES
SOIL CHEMISTRY
SOILS
SORPTION
SULFATES
SULFUR COMPOUNDS
UPTAKE
VARIATIONS