Investigations concerning mechanisms and kinetics of the inorganic sulfur-bonding in acidified forest soils and identification of the solid-phases of sulfur

BITÖK-S 9

From 01/1995 to 12/1997

Principal Investigator: Stefan Peiffer
Grant: 0339476 B Vorhersage und Erklärung des Verhaltens und der Belastbarkeit von Ökosystemen unter veränderten Umweltbedingungen

Inorganic sulfur retention is an important process of acid-base chemistry of acid forest soils, yet the binding forms of retained S are not completely understood. Column experiments with the sand fraction of two rockforming minerals (albite and gibbsite) have been set up to study sulphate-retention-kinetics in water-saturated environments with various pH and various concentrations of Al3+ and SO42-. Temperature is kept constant at 10°C. We applied several instrumental analytical methods to identify solid phases of inorganic sulfur in acid forest soils. In preliminary experiments we successfully tested: Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Infrared Spectroscopy (IR). For these experiments we used untreated material and pretreated material that was allowed to react at 100°C for two hours with 0.1 N sulfuric acid. Additional methods are to be applied: Secondary Ion Mass Spectrometry (SIMS), Differential Thermal Analysis (DTA), X-ray Fluorescence Analysis (XFA), Atomic Force Microscopy (AFM) and Laser Microprobe Mass Analysis (LAMMA).