Vazquez Martinez, Oscar C
(2011)
Effects of Acid Mine Drainage on the Release of Aluminum from Clay Minerals.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The objective of this PhD research was to investigate the leaching of acid clays with acid mine/rock drainages (AMD/ARD) typically found in U.S. soils and develop information supporting the phenomena of the release of elevated concentrations of aluminum from such interactions. In Pennsylvania, reported aluminum concentrations in discharge samples from 140 abandoned coal mines showed that over 50% of these water samples presented dissolved aluminum concentrations over 1 mg/L. Aluminum at these levels can be detrimental to freshwater aquatic ecosystems and thus, these data suggest that aluminum-containing AMD/ARD is a major problem in USA. Leaching of smectite clays with different synthetic AMD/ARD were conducted to explore the effect of common cations in pyritic and brackish/saline AMD/ARD, on the release of aluminum from clays at pH between 2 and 3 frequently found in the field. The major finding of this research is that the release of aluminum from smectite clays is enhanced by Fe2+, potassium (KCl) and sodium (NaCl) salts in AMD/ARD. The major mechanisms involved in the release of aluminum from these clays were: cation-exchange dominating the short-term and clay dissolution dominating the long-term leaching of aluminum from smectites. These results were consistent with the low iron concentrations and high aluminum concentrations observed in some field AMD/ARD.The outcome of this research adds new knowledge to the field of environmental science and engineering by pointing out the significant effects that K and Na salts in AMD/ARD have on the release of aluminum from clays. These K and Na salts in AMD/ARD promote the release of Al from field clays leading to deleterious effects on aquatic ecosystems. Thus, this research contributes to a better understanding of the occurrence of elevated levels of aluminum in AMD/ARD and will assist others to consider alternative remediation strategies in those locations where the in situ generation of high concentration of aluminum discharges may occur. The observation of greater concentrations of aluminum in leachate produced by brackish AMD/ARD implies that highway deicing salts in road runoff could aggravate the leaching of aluminum from pyritic rocks used as fill or exposed in road cuts.
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Details
Item Type: |
University of Pittsburgh ETD
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Status: |
Unpublished |
Creators/Authors: |
Creators | Email | Pitt Username | ORCID |
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Vazquez Martinez, Oscar C | ocv1@pitt.edu | OCV1 | |
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ETD Committee: |
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Date: |
27 June 2011 |
Date Type: |
Completion |
Defense Date: |
22 March 2011 |
Approval Date: |
27 June 2011 |
Submission Date: |
3 February 2011 |
Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
Institution: |
University of Pittsburgh |
Schools and Programs: |
Swanson School of Engineering > Civil and Environmental Engineering |
Degree: |
PhD - Doctor of Philosophy |
Thesis Type: |
Doctoral Dissertation |
Refereed: |
Yes |
Uncontrolled Keywords: |
ALUMINUM; CLAY; ACID MINE DRAINAGE; SMECTITE; ACID ROCK DRAINAGE |
Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-02032011-092047/, etd-02032011-092047 |
Date Deposited: |
10 Nov 2011 19:31 |
Last Modified: |
15 Nov 2016 13:36 |
URI: |
http://d-scholarship.pitt.edu/id/eprint/6327 |
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