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| Titel |
A new method for As(V) removal from waters by precipitation of mimetite Pb5(AsO4)3Cl on Pb-activated zeolite |
| VerfasserIn |
Maciej Manecki, Urszula Buszkiewicz |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128552
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| Publikation (Nr.) |
 EGU/EGU2016-8551.pdf |
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| Zusammenfassung |
| A new method for removal of arsenate AsO43− ions from aqueous solutions is
proposed. The principle of the method stems from precipitation of very insoluble
crystalline lead arsenate apatite (mimetite Pb5(AsO4)3Cl) induced by bringing in contact
Pb-activated zeolite and As-contaminated water in the presence of Cl−. Zeolite is activated
by sorption of Pb2+ followed by washing with water to remove the excess of Pb
and to desorbe weakly adsorbed ions. Lead adsorbed on zeolite is bound strong
enough to prevent desorption by water but weak enough to undergo desorption
induced by heterogeneous precipitation of mimetite nanocrystals on the surface of
zeolite.
The experiment consisted of two steps. In the first step, aliquots of 0.5 g of natural
clinoptilolite zeolite (from Zeocem a.s., Bystré, Slovak Republic) were reacted with 40 mL of
solutions containing 20, 100, 500, and 2000 mg Pb/L (pH =4.5; reaction for 30 minutes
followed by centrifugation). The amount of Pb sorbed was calculated from the drop
of Pb concentration in solution. Centrifuged zeolite was washed three times by
mixing with 10 mL of DDI water, followed by centrifugation. No Pb was detected in
the water after second washing. Wet pulp resulting from this stage was exposed
to solutions containing 70 mg/L Cl− and various concentrations of AsO43− (2
and 100 mg As/L; pH=4). Complete removal of As was observed for 2 mg As/L
solutions mixed with zeolite-20 and zeolite-100. The precipitation of mimetite
Pb5(AsO4)3Cl in the form of hexagonal crystals ca. 0.25 μm in size was observed using
SEM/EDS.
This work is partially funded by AGH research grant no 11.11.140.319. |
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