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dc.contributor.authorPalomino Ore, Sheyla Bethsyen_US
dc.date.accessioned2018-07-04T08:00:23Z
dc.date.available2018-07-04T08:00:23Z
dc.date.issued2018-07-03en_US
dc.identifier.othervt_gsexam:14768en_US
dc.identifier.urihttp://hdl.handle.net/10919/83860
dc.description.abstractNeutralization by limestone is a common treatment for acid mine drainage (AMD). The effectiveness of using limestone to treat AMD can be reduced by aluminum (Al) and iron (Fe) oxyhydroxide coatings that form on the limestone, because the coatings inhibit the transport, and thus neutralization, of hydrogen ions (H+) derived from acid mine drainage. I used mixed flow reactor experiments to investigate the effect of Al coatings on the diffusion of H+ to the surface of limestone and to quantify how those Al coatings affect the limestone dissolution rate. Experiments used acidic Al sulfate solutions with initial Al concentrations ranging from 0.002 M to 0.01 M (32 to 329 ppm) and pH values ranging from 3.7 to 4.2, which are typical of conditions found at AMD sites. Cleaved pieces of Iceland spar calcite were used as a proxy for limestone. The pH was measured in the effluent to determine the rate of H+ consumption. Effluent solutions were analyzed for Al, calcium (Ca) and sulfur (S) using inductively coupled plasma optical emission spectroscopy (ICP OES). Examination of the precipitated coatings using x-ray diffraction indicated that amorphous poorly crystalline gibbsite is the primary Al coating but scanning electron microscope analysis also suggests the possible presence of a poorly crystalline sulfur containing phase, such as hydrobasaluminite. The experimental data were used to calculate the diffusion coefficient of H+ through the Al coatings. The calculated diffusion coefficient for H+, assuming a gibbsite and/or hydrobasaluminite layer, ranged between 10-13 to 10-11 m2/sec, that are significantly lower than in pure water.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis item is protected by copyright and/or related rights. Some uses of this item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectAcid mine drainageen_US
dc.subjectlimestone drainsen_US
dc.subjectaluminumen_US
dc.subjectoxyhydroxideen_US
dc.subjectcoatingsen_US
dc.titleEffect of aluminum oxyhydroxide coatings on the performance of limestone drainsen_US
dc.typeThesisen_US
dc.contributor.departmentGeosciencesen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeosciencesen_US
dc.contributor.committeechairSchreiber, Madeline E.en_US
dc.contributor.committeememberRimstidt, James Donalden_US
dc.contributor.committeememberSeal, Robert Rhodesen_US
dc.contributor.committeememberChermak, John Alanen_US


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