Integration of nanofiltration and bipolar electrodialysis for valorization of seawater desalination brines: production of drinking and waste water treatment chemicals
Nanofiltration (NF), as a selective Mg(II) and Ca(II) separation and concentration treatment, and electrodialysis with bipolar membranes (EDBM) were evaluated for the valorization of seawater desalination reverse osmosis brines (60 NaCl/L) to produce both rich Mg(II) and Ca(II) brines for phosphate...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2016 |
| 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:2117/90252 |
| Acceso en línea: | https://hdl.handle.net/2117/90252 https://dx.doi.org/10.1016/j.desal.2015.12.013 |
| Access Level: | acceso abierto |
| Palabra clave: | Sewage--Purification Drinking water--Purification Saline water conversion Divalent ions Seawater brine Chemical precipitation Purification Acid–base production Dessalinització de l'aigua Aigua potable -- Tractament Aigües residuals -- Depuració -- Tractament químic Àrees temàtiques de la UPC::Enginyeria química::Química del medi ambient::Química de l'aigua |
| Sumario: | Nanofiltration (NF), as a selective Mg(II) and Ca(II) separation and concentration treatment, and electrodialysis with bipolar membranes (EDBM) were evaluated for the valorization of seawater desalination reverse osmosis brines (60 NaCl/L) to produce both rich Mg(II) and Ca(II) brines for phosphate recovery and HCl and NaOH as chemicals for desalination treatments. A NF pilot plant, using NF270 membranes at 20 bar, provided a rich Mg(II) (8.3 g Mg(II)/L) and Ca(II) (2.1 g Ca(II)/L) brine on the concentrated stream with enrichment factors of 3.2 for Mg(II) and 2.5 for Ca(II). The NF permeate stream containing 50 ± 2 g NaCl/L was treated to remove residual Mg(II) (760 mg/L) and Ca(II) (415 mg/L) by chemical precipitation with Na2CO3 and NaOH before the EDBM unit. Divalent cations free brine containing NaCl (50 g NaCl/L) were fed into the EDBM stack in order to produce NaOH and HCl under recirculation configuration. Constant voltage and acid and base concentrations at different initial conditions were evaluated to obtain the maximum acid and base concentration (approximately 1 M NaOH/HCl) at 9 V. No substantial effect of initial acid and base concentrations on the overall performance was observed. An energy consumption of 2.6 kWh/kg NaOH and current efficiency of 77 ± 3% were calculated |
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