From nanofiltration membrane permeances to design projections for the remediation and valorisation of acid mine waters
Acidic Mine Waters (AMWs) are characterised by high acidity (pH¿<¿3) as H2SO4 and elevated contents of metals (Al, Fe, Cu, Zn), including rare earth elements (REEs). Due to the exhaustion of minable REE containing-minerals, AMWs are increasingly regarded as an alternative source of REEs. Among th...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/335785 |
| Acceso en línea: | https://hdl.handle.net/2117/335785 https://dx.doi.org/10.1016/j.scitotenv.2020.139780 |
| Access Level: | acceso abierto |
| Palabra clave: | Nanofiltration Membranes (Technology) Resource recovery Acidic mine waters NF270 Desal DL Aigües àcides -- Depuració Nanofiltració Membranes (Tecnologia) Àrees temàtiques de la UPC::Enginyeria química |
| Sumario: | Acidic Mine Waters (AMWs) are characterised by high acidity (pH¿<¿3) as H2SO4 and elevated contents of metals (Al, Fe, Cu, Zn), including rare earth elements (REEs). Due to the exhaustion of minable REE containing-minerals, AMWs are increasingly regarded as an alternative source of REEs. Among the different alternatives for the pre-concentration of AMWs required to make the REE extraction possible, nanofiltration (NF) membranes emerge as a promising technology because they not only successfully reject multivalent ions (metals), allowing its concentration in the retentate stream, but also permit the transport of monovalent ones, such as H+ and HSO4-, allowing the recovery of sulphuric acid in the permeate. Despite this potential of NF, there is still a lack of modelling tools for predicting the performance of NF membranes because of its dependence on solution composition, membrane properties and interaction between both. In this study, a prediction tool based on the Solution-Electro-Diffusion model (including the effect of solution composition) was developed and experimentally validated for the application of two polyamide-based NF membranes (NF270 and Desal DL) for the recovery of REEs and H2SO4 from three different synthetic solutions mimicking AMWs (pH¿1.0, 60¿mg/L REEs and, 25–600¿mg/L Al, Cu, Ca and Zn) differing in their Fe concentration (0–2125¿mg/L). Metals were effectively rejected (>98%), whereas H2SO4 was transported across the membrane (H+ rejections <30%). The mathematical model was able to predict the performance of both membranes as well as the potential scaling events associated with Fe and Al hydroxides and hydroxy-sulphates. |
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