Perchlorate is known to adversely affect the thyroid gland functions including
iodide take up, thus perchlorate should be removed from drinking water. Bituminous
coal-based activated carbon (AC) has been used for perchlorate removal in past years.
Virgin carbon and carbon modified by oxidation with HNO3, NaOH and H2O2 were
examined in this study for their ability to remove perchlorate by reduction or adsorption
mechanisms. Surface functional groups formed on the modified AC (MAC) were
examined with diffuse reflectance infrared spectrometry. Inhibition of perchlorate
removal onto MAC by various anions ( - Cl , -
3 NO , and - 2
4 SO ) and solution pH (4.5, 7.2
and 10.5) were examined to characterize the MACs before an electrochemical reaction
was performed.
Surface functional groups were increased by oxidation. Groups that were found
on the carbon include, but are not limited to lactone, quinine, carboxylate, and nitrogenoxygen
groups. The effect of pH on removal of perchlorate by MAC was greatly
affected by the change in the zero point charge (ZPC) induced on the carbon by
modification. Virgin carbon also experienced difficulty in removing perchlorate when
solution pH was above the ZPC. Anion inhibition varied with the modification process.
-
3 NO inhibited perchlorate removal only by the virgin carbon. The other anions showed
no major effects on the removal efficiency of perchlorate by the carbons. Electrochemical processes did not show favorable results in removal of
perchlorate. The dominant mechanism of perchlorate removal during desorption tests
was adsorption onto the carbon surfaces via ion exchange.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1085 |
| Date | 15 May 2009 |
| Creators | Langille, Meredith Caitlyn |
| Contributors | Kramer, Timothy |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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