Journal
| 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 Posted by Mylah Tabelin |
| Authors | Carlito Baltazar Tabelin, Ryan D. Corpuz, Toshifumi Igarashi, Mylah Villacorte-Tabelin, Richard Diaz Alorro, Kyoungkeun Yoo, Simit Raval, Mayumi Ito, Naoki Hiroyoshi |
| Publication date | 2020/5/20 |
| 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 wastesâÂÂsoluble salts (melanterite, FeSO4÷7H2O) and metal oxides (hematite, Fe2O3)âÂÂon AMD formation and As mobility under acidic conditions (pH 1.5âÂÂ4) 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 directlyâÂÂby supplying H+ and/or oxidants (Fe3+)âÂÂand indirectlyâÂÂvia changes in the nature of oxidation layer formed on pyriteâÂÂinfluenced 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 âÂÂstrongâ coating on pyrite that suppressed the mineralâÂÂs 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 | https://doi.org/10.1016/j.jhazmat.2020.122844 |
| URL | https://www.sciencedirect.com/science/article/abs/pii/S0304389420308335 |