Nowadays, chemical industries produce high amounts of concentrated effluents and/or aqueous solutions rich in heavy metals or rare-earth elements. Then, industries wanted to reduce the concentration of these streams or valorize these elements. For this reason, in this work we propose the use of a new electrodialysis-based technology, named selectrodialysis (SED), in order to reduce the effluent concentration, separate monovalent from divalent ions, and at the same time concentrate them in order to be reused in the same industry. By means of SED it could be possible to valorize heavy metals, such as zinc or arsenic, from an industrial acid effluent. The main objective of this work is to separate zinc and arsenic in two different streams and also obtain an almost desalinated feed stream. Several experiments were carried out in a lab-scale set-up (ED 64-4 from PCCell, Germany) by means of monovalent selective cationic (MCV) and standard ion-exchange membrane (IXM) from two different companies: PCCell and Fujifilm, which they have different synthesis processes and physical-chemical properties. Two membrane configurations were used: one using MVC and standards Fujifilm membrane, and the second one mixing MCV membrane from Fujifilm with standards IXM from PCCell. Experiments were conducted using synthetic acid sulfuric solution containing ZnSO 4 and HNa 2 AsO 4 salts. Four main streams were differentiated in the SED experiments: electrode rinse, feed solution (which will be desalinated), Zn-rich stream (the Zn concentration would increase over time) and As-rich stream (the As concentration would increase over time). For all the experiments, a total desalination of the acid feed stream, containing ZnSO 4 and HNa 2 AsO 4, was achieved; while As and Zn were separated and concentrated in the corresponding streams. Best concentration factors (> 500) for Zn were obtained with the first membrane configuration (Fujifilm membranes) in comparison with the values reached (< 400) through the combination of MVC Fujifilm membranes and standard PCCell ones. Additionally, almost the same energy consumption values were obtained for each membrane combination, although lower values were achieves for the Fujifilm combination around 6.4 kWh/kg ZnSO 4, whereas 8.2 kWh/kg ZnSO 4 was calculated for the PCCell-Fujifilm combination. Besides, the Fujifilm membranes configuration obtained a higher faradic yield, so it could be concluded that this is the more appropriate membrane combination for the Zn/As separation
Lopez, J.; Reig, M.; Vecino, X.; Valderrama, C.; Gibert, O.; Yaroshchuk, A.; Cortina, J. International Congress on Membranes and Membrane Processes Data de presentació: 2017-07-29 Presentació treball a congrés
Lopez, J.; Reig, M.; Licon, E.; Gibert, O.; Yaroshchuk, A.; Torres, E.; Ayora, C.; Cortina, J. International Conference on Desalination Using Membrane Technology Data de presentació: 2017-04-03 Presentació treball a congrés
Generally, in the tertiary process of industrial wastewater treatment plants, the content of ammonia from industrial effluents decreases from 0.5-2 g/L to 0.05-0.1 g/L. Nevertheless, in order to accomplish the EU legislation, the amount of ammonia in the wastewater streams should be lower than 1 mg/L . Ammonia presents serious environmental problems cause by its excess in the ecosystem generates the eutrophication phenomenon . Therefore, the quantity of ammonia in wastewater effluents can be reduced by the use of novel, low-cost and eco-friendly membrane technology such as liquid-liquid membrane contactors (LLMCs). The current work has a double objective: the use of hollow fiber LLMCs as ammonia separation and concentration step as well as the valorization and production of ammonium nitrate as liquid fertilizer solution. Several closed-loop experiments were carried out using the hollow fiber LLMCs lab mode (2.5x8 Liqui-Cel Membrane Contactor X-50 PP fiber, supplied by 3M Company) during 4 h at room temperature (25 ºC). Following the methodology described in previous works , the ammonia feed solution (1800 mg/L, pH=12), was pumped through the lumen side of the LLMC contactor at 7.5 cm 3 /s, whereas the stripping nitric acid solution (0.5 mol/L) was circulated into the shell side in a counter current mode. The volumes of the feed and stripping solutions were 30 L and 0.5 L, respectively. Samples were taken from the feed solution tank for the determination of the total ammonium concentration. The results showed that the recovery of ammonia was about 80-90% after the LLMC treatment. Additionally, the concentration of ammonia as ammonium nitrate was around 6% (w/w). Overall, these results highlight the possibility to separate and valorize ammonia from industrial streams for producing liquid fertilizers.
Lopez, J.; Reig, M.; Gibert, O.; Yaroshchuk, A.; Torres, E.; Ayora, C.; Cortina, J. International Conference on Sustainable Water Processing Data de presentació: 2016-09-12 Presentació treball a congrés
Acid mine drainage (AMD) is a by-product of mining industry which presents a low pH and a high content of sulphate ion and heavy metal dissol ved. This water contains a toxic mixture that will damage aquatic life, destroys ecosystems and t aints water. Traditional methods like lime neutralization for sulphate and metal precipitation involves a high amount of reactive and high costs. Due to the ability of nanofiltration membran es to reject multivalent cations, synthetic AMD was filtered with two types of commercial available membranes: NF-270 and Hydracore 70-pHT. The experiments were carried in a spiral-wound modu le. Feed solution contains 4.6 g/L Na + , 1 g/L Fe 2+ , 0.6 g/L Cu 2+ and 0.5 g/L Zn 2+ and the pH was changed by adding sulphuric acid. F or NF-270 membrane, divalent metal ion rejections were higher than 90 %, sodium rejection was higher than 80 % and sulphate rejection was higher than 85 %. For Hydracore 70pHT, divalent metal ion and sodium rejections were higher than 60 % and sulphate rejection was higher than 65%. NF-270 exhibits better performance than Hydrac ore 70pHT, achieving higher metal rejections and higher fluxes than Hydracore 70pHT, which makes it suitable for acid mine treatment