Browsing by Author "Druschel, Greg"

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    The Effects of Surfactants on Colloidal, Nanoparticulate, and Dissolved Sulfur
    (Office of the Vice Chancellor for Research, 2016-04-08) Kurek, Martin; Druschel, Greg; Gilhooly, William P., III
    Elemental sulfur is generally insoluble in water unless in the presence of a surfactant. This phenomenon was investigated by Steudel and Holdt in 1988 by filtering mixtures of sulfur, water, and surfactants through a 0.45 micron filter; however, since then sulfur nanoparticles smaller than 0.45 microns have been detected. The smaller than expected particle size suggests that the distribution of elemental sulfur in water with surfactants may be partitioned into colloidal, nanoparticulate, and truly dissolved components. Experiments have been conducted measuring the sulfur solubility in water with several chemical surfactants and varying filter sizes smaller than 0.45 microns. These experiments were conducted under equilibrium conditions with the solubility being measured using HPLC and square wave voltammetry. Kinetic studies detailing the solubility of sulfur with the surfactants over time have also been investigated. Data regarding the size and occurrence of sulfur nanoparticles present in water and the surfactants has been collected as well to give a complete description of the system under examination. Sulfur isotope fractionation of the dissolved sulfur species is also an interesting component of the system that is currently being investigated using stable isotope ratio mass spectrometry of 34S.
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    Geochemical analysis of four late middle Pennsylvanian cores from Southern Indiana
    (2014-12) Broach, Clinton M.; Gilhooly, William III; Druschel, Greg; Licht, Kathy J.
    The shale and mudstone directly superjacent to Desmoinesian coal seams of southern Indiana (Springfield, Houchin Creek, Survant, and Seelyville coals) were initially deposited under marine waters and are shown to exhibit high concentrations of organic carbon, sulfur and redox-sensitive metals (Mo, V, Ni, Fe, and U) that were sequestered during times of benthic anoxia and intermittent to sustained euxinia (anoxic and sulfidic). Strata upsection display geochemical signatures that indicate increasingly oxic and nearshore sedimentation that mirrors cyclothemic sequence stratigraphic trends Carbon source, nearshore and offshore proximity, freshwater and marine influence, and redox conditions of the epeiric sea overlying southern Indiana during the Late Middle Pennsylvanian were identified and tracked throughout the deposition of four drill cores of the Petersburg, Linton and Staunton Formations. Carbon, nitrogen, and sulfur data (total organic carbon [TOC], total nitrogen [TN], and total sulfur [TS]); paleoredox proxies ([Mo/Al], [V/Al], [Th/U], [Fetot/Al]); organic carbon isotopes (δ13Corg); and detrital influx concentrations (Zr) were all used in conjunction with lithological and paleontological interpretations to better understand the mode of deposition in this unique midcontinent ancient epeiric sea. Geochemical results when combined with lithologic and paleontologic interpretations reveal a dynamic environmental system where water column geochemistry varies with the influence of variable magnitudes of epeiric seawater flooding on the extensive peatlands of equatorial Late Middle Pennsylvanian southern Indiana.