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Articles 31 - 33 of 33
Full-Text Articles in Physical Sciences and Mathematics
Improved Identification Of Sulfidic Soil Materials By A Modified Incubation Method, Leigh Sullivan, Nicholas Ward, Richard Bush, Edward Burton
Improved Identification Of Sulfidic Soil Materials By A Modified Incubation Method, Leigh Sullivan, Nicholas Ward, Richard Bush, Edward Burton
Associate Professor Edward D Burton
This study examines the acidification behaviour and rate of sulfidic-sulfur oxidation in the incubation method that is currently used in soil taxonomies to identify sulfidic materials, for some clayey textured soil materials. ‘Sulfidic’ in these taxonomies identifies that a soil material is capable of becoming extremely acidic (i.e. pH < 4) as a result of oxidation of sulfide minerals contained in that soil material. As well as examining incubation slabs of acid sulfate soil materials with the standard 10 mm thickness, the utility of thinner (i.e. 2 mm thick) incubation slabs of these soil materials for identification of sulfidic soil materials …
Reductive Transformation Of Iron And Sulfur In Schwertmannite-Rich Accumulations Associated With Acidified Coastal Lowlands, Edward Burton, Richard Bush, Leigh Sullivan, David Mitchell
Reductive Transformation Of Iron And Sulfur In Schwertmannite-Rich Accumulations Associated With Acidified Coastal Lowlands, Edward Burton, Richard Bush, Leigh Sullivan, David Mitchell
Associate Professor Edward D Burton
We examined the transformations of Fe and S associated with schwertmannite (Fe8O8(OH)6SO4) reduction in acidified coastal lowlands. This was achieved by conducting a 91 day diffusive-flux column experiment, which involved waterlogging of natural schwertmannite- and organic-rich soil material. This experiment was complemented by short-term batch experiments utilizing synthetic schwertmannite. Waterlogging readily induced bacterial reduction of schwertmannite-derived Fe(III), producing abundant pore-water FeII, SO4 and alkalinity. Production of alkalinity increased pH from pH 3.4 to pH 6.5 within the initial 14 days, facilitating the precipitation of siderite (FeCO3). Interactions between schwertmannite and FeII at pH 6.5 were found, for the first time, …
A Sequential Extraction Procedure For Acid-Sulfate Soils: Partitioning Of Iron, Salirian Claff, Leigh Sullivan, Edward Burton, Richard Bush
A Sequential Extraction Procedure For Acid-Sulfate Soils: Partitioning Of Iron, Salirian Claff, Leigh Sullivan, Edward Burton, Richard Bush
Associate Professor Edward D Burton
A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate soil materials. This sequential extraction procedure employs six steps to quantify (1) exchangeable (magnesium chloride extractable), (2) acid (hydrochloric acid) soluble, (3) reactive organic-bound (pyrophosphate extractable), (4) crystalline oxide (citrate buffered dithionite (CBD)) extractable, (5) pyrite-bound (nitric acid extractable) and (6) residual (acid/peroxide digestible) forms of iron. Given its intended use for acid sulfate soil materials that frequently contain pyrite, a primary aim of this new sequential extraction procedure was to differentiate iron …