| Title |
Acid mine drainage formation and arsenic mobility under strongly acidic conditions: Importance of soluble phases, iron oxyhydroxides/oxides and nature of oxidation layer on pyrite |
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Authors |
Carlito Baltazar Tabelin, Ryan D. Corpuz, Toshifumi Igarashi, Mylah Villacorte-Tabelin, Richard Diaz Alorro, Kyoungkeun Yoo, Simit Raval, Mayumi Ito, Naoki Hiroyoshi |
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Publication date |
2020/5/20 |
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Journal |
Journal of Hazardous Materials |
| Volume |
399 |
| Pages |
122844 |
| Publisher |
Elsevier |
| Abstract |
Acid mine drainage (AMD) formation and toxic arsenic (As) pollution are serious environmental problems encountered worldwide. In this study, we investigated the crucial roles played by common secondary mineral phases formed during the natural weathering of pyrite-bearing wastes脙垄脗聙脗聰soluble salts (melanterite, FeSO4脙聜脗路7H2O) and metal oxides (hematite, Fe2O3)脙垄脗聙脗聰on AMD formation and As mobility under acidic conditions (pH 1.5脙垄脗聙脗聯4) prevalent in historic tailings storage facilities, pyrite-bearing rock dumps and AMD-contaminated soils and sediments. Our results using a pyrite-rich natural geological material containing arsenopyrite (FeAsS) showed that melanterite and hematite both directly脙垄脗聙脗聰by supplying H+ and/or oxidants (Fe3+)脙垄脗聙脗聰and indirectly脙垄脗聙脗聰via changes in the nature of oxidation layer formed on pyrite脙垄脗聙脗聰influenced pyrite oxidation dynamics. Based on SEM-EDS, DRIFT spectroscopy and XPS results, the oxidation layer on pyrite was mainly composed of ferric arsenate and K-Jarosite when melanterite was abundant with/without hematite but changed to Fe-oxyhydroxide/oxide and scorodite when melanterite was low and hematite was present. This study also observed the formation of a mechanically 脙垄脗聙脗聵strong脙垄脗聙脗聶 coating on pyrite that suppressed the mineral脙垄脗聙脗聶s oxidation. Finally, As mobility under acidic conditions was limited by its precipitation as ferric arsenate, scorodite, or a Fe/Al arsenate phase, including its strong adsorption to Fe-oxyhydroxides/oxides. |
| Index terms / Keywords |
Acid mine drainage; Arsenic; Secondary minerals; Scorodite; Pyrite oxidation |
| DOI |
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| URL |
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Mindanao State
University - Iligan Institute of Technology