Das Projekt "Investigations Concerning Mechanisms and Kinetics of the Inorganic Sulfur-Bonding in Acidified Forest Soils and Identification of the Solid-Phases of Sulfur - Part S9" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Lehrstuhl für Bodenkunde und Bodengeographie durchgeführt. 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 sulfate-retention-kinetics in water-saturated environments with various pH and various concentrations of Al3+ and SOtief4hoch2-. Temperature is kept constant at 10 degC. 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 degC 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).