DISSOLUTION OF β-MNOOH PARTICLES BY LIGANDS: PYROPHOSPHATE, ETHYLENEDIAMINETETRAACETATE, AND CITRATE - THE EFFECT OF PH AND LIGHT
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dc.contributor.author | Klewicki J.K. | |
dc.contributor.author | Morgan J.J. | |
dc.date.accessioned | 2021-01-09T05:51:37Z | |
dc.date.available | 2021-01-09T05:51:37Z | |
dc.date.issued | 1999 | |
dc.identifier | https://elibrary.ru/item.asp?id=184839 | |
dc.identifier.citation | Geochimica et Cosmochimica Acta, 1999, , 19, 3017-3024 | |
dc.identifier.issn | 0016-7037 | |
dc.identifier.uri | https://repository.geologyscience.ru/handle/123456789/22506 | |
dc.description.abstract | Experiments describing the extent of dissolution of β-MnOOH(s) suspensions vs. time using measurements of both total dissolved Mn and Mn(III) complex species show that the ligands pyrophosphate (P2O74-), ethyelenediaminetetraacetate (EDTA4-), and citrate (CIT3-), each in large excess with respect to solids concentration and estimated surface sites, promote dissolution by different mechanisms and at different rates. Pyrophosphate dissolution of β-MnOOH yields predominately the Mn(III)HP2O7(aq) complex. EDTA4- causes reductive dissolution, with no Mn(III) complexes of the ligand observed in solution. Citrate causes ligand-promoted dissolution in the initial stages of reaction, after which solution phase reactions bring about reduction of Mn(III)CIT(aq) to Mn(II) solution species. Rates of dissolution at circum-neutral pH show somewhat higher rates at lower pH. Initial rates of ligand-promoted dissolution, R0, by pyrophosphate were in the range ~ 8 x 10-8 to 6 x 10-7 mol g-1 s-1 between pH 8 and 6.5. For reductive dissolution by EDTA, initial rates, R0, ranged from ~ 8 x 10-7 to 2 x 10-6 mol g-1 s-1 between pH 8 and 7. At pH 6.3, initial dissolution rate with citrate was ~ 6 x 10-6 mol g-1 s-1. Results of this exploratory study of MnOOH dissolution by ligands at circum-neutral pH suggest that manganese cycling in natural waters may involve loss of MnOOH particles promoted by naturally-occurring or pollutant ligands with formation of Mn(III) aqueous complexes. | |
dc.title | DISSOLUTION OF β-MNOOH PARTICLES BY LIGANDS: PYROPHOSPHATE, ETHYLENEDIAMINETETRAACETATE, AND CITRATE - THE EFFECT OF PH AND LIGHT | |
dc.type | Статья |
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