Clinoptilolite and iron sorption/desorption under multiple pH conditions : Testing a substrate for passive treatment of acidic, iron-rich solutions
© 2021 Water Environment Federation.
| Veröffentlicht in: | Water environment research : a research publication of the Water Environment Federation. - 1998. - 93(2021), 9 vom: 25. Sept., Seite 1714-1721 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2021
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| Zugriff auf das übergeordnete Werk: | Water environment research : a research publication of the Water Environment Federation |
| Schlagworte: | Journal Article acidity clinoptilolite desorption metal retention passive treatment sorption zeolite 12173-10-3 Zeolites mehr... |
| Zusammenfassung: | © 2021 Water Environment Federation. Equilibrium sorption and desorption experiments were conducted with clinoptilolite to evaluate the potential sorption/desorption of iron during different pH conditions. Sorption experiments indicated a partitioning of 0% to 17% of the iron in solution given pH of 2 to 4. The pH 2 solution was able to desorb 70% of the iron that was captured from a pH 3 solution. The largest desorption and sorption of iron and corresponding pH represent the end points of iron capture primarily by sorption/exchange. These endpoints are the estimated pHpzc of 2.5 and the initial precipitation point of iron(II) at pH ~3.5. This acidity range is where clinoptilolite is able to capture iron without precipitation or the occurrence of full surface protonation. The inability of the highest acidity to remove all sorbed iron represents the greater bound iron that will not readily desorb with a change in pH. This retained iron creates a metastable state of the clinoptilolite that has a lower sorption capacity but reflects the ability of clinoptilolite to retain a sorbed transition metal with changes in pH. As pH varies, clinoptilolite may evolve in a sequence of metastable states reflective of its ability to capture or retain metals. PRACTITIONER POINTS: Clinoptilolite is a capable reactive substrate, but its sorption/exchange effectiveness at low and variable pH and ability to retain captured metals was unknown. Clinoptilolite retains its metal capture properties to a pH of 2.5 where surface protonation and mineral degradation likely occurs. The ability of clinoptilolite to retain captured iron under greater acidity reflects an evolution of its sorption/retention capacity |
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| Beschreibung: | Date Completed 08.09.2021 Date Revised 08.09.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1554-7531 |
| DOI: | 10.1002/wer.1557 |