Reig, M.; Vecino, X.; Valderrama, C.; Gibert, O.; Cortina, J. Separation and purification technology Vol. 195, p. 404-412 DOI: 10.1016/j.seppur.2017.12.040 Data de publicació: 2017-12-19 Article en revista
In this work, selectrodialysis (SED) was used to separate arsenic (As(V)) from copper (Cu(II)) and (Zn(II)) of acidic metallurgical process streams by integrating non-selective and selective membranes. The separation process is determined by the chemical speciation of the involved elements. In this case, As(V) is mainly present as anionic species (H2AsO4-), while Cu(II) and Zn(II) are mainly present as cationic species although partially complexed as neutral complexes (CuSO4 and ZnSO4). A lab set-up was used to conduct the experimental tests with different type of standard and mono-selective ion-exchange membranes. The results obtained showed that by SED configuration it was possible to recover around 80±0.2 % of Cu(II), 87±0.2 % of Zn(II) and 95±0.3 % of As(V) from the feed solution to the rich-product streams with an energy consumption of 2.6±0.2 kWh/kg CuSO4+ZnSO4. Furthermore, a Cu/Zn-rich stream with a purity of both divalent cations of 99.8 % (0.02 % of As(V)) was achieved by means of SED. Overall, the results herein gathered suggest that SED is an efficient separation technology for Cu(II) and Zn(II) recovery from mining and metallurgical acidic streams.
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
Human hair contains fatty acids (palmitic, palmitoleic, oleic and stearic acid) that prevent hair dryness and avoid lower hair density of the scalp that can be caused when hair is dyed. These acids are also present in the composition of the amphoteric biosurfactant obtained from corn steep liquor, an agro-industrial stream generated by the corn wet-milling industry. This biosurfactant has a molecular weight of 1542 Da, with a similar mass spectrum to that of Fengycin, a biosurfactant produced by Bacillus subtilis strains. Few studies exist in the literature on the interaction of hair and biosurfactants, nor are there studies on the influence of micelle formation on biosurfactant adsorption capacity. Moreover, this is supposedly the first work in which a biosurfactant is applied to dyed hair. Different concentrations of biosurfactant were applied to dyed hair between 20–50 °C during 2–30 min of treatment. Theoretical models were obtained, which allowed the prediction of the amount of biosurfactant that can be entrapped by dyed hair. A maximum capacity of 10 549 µg g-1 was achieved at 295 mg L-1 of biosurfactant, thus it could be observed that dyed hair mainly adsorbed the biosurfactant above its critical micellar concentration, at which point the biosurfactant is in micellar form. Furthermore, this treatment maintains the dyed hair structure in a good state.
There is an environmental challenge for the metallurgical and mining industries, especially for smelting, mining and processing of copper, due to the numerous environmental regulations imposed as well as the human health impact of heavy metal pollution. Copper metallurgical
processes is generating complex residuals streams with high copper contents where it is
accompanied by other base metals as zinc, nickel and cadmium and toxic non-metals as arsenic and bismuth, among others. Due to the economic value of such copper streams several techniques such as chemical precipitation, adsorption and ion exchange, among others, are being proposed for its selective separation and concentration. In this study the use of ion selective membrane electrodialysis (IX-ED) has been evaluated to achieve a double objective: the separation and concentration of Cu(II) from streams containing mixtures of H2SO4/H3AsO4 by using an ion exchange membrane process with cation monovalent selective membranes, named ‘‘selectrodialysis (SED)”.
The SED configuration is based on conventional ED (PCCell ED 64–004 with a cell of 11×11cm) by adding one monovalent selective cation exchange (MVC) membrane between the standard anion (AEM) and cation exchange (CEM) membranes. In addition, the SED system
was composed by four streams: electrode rinse (0.1 M Na2SO4), feed solution (10 g/L CuSO4 and 8.5 g/L Na2HAsO4, pH=2.3), Cu-rich product (0.1 M H2SO4) and As-rich product (0.1 M H2SO4). The initial volume introduced in each tank was 1L, the flow rates were set at 90–100 L/h in the electrode rinse stream and 15–20 L/h in the others, and the voltage was constant at 7V.
The preliminary results show that the feed stream was deconcentrated from approximately 7.5 to 0.4 g/L of CuSO4 reaching arsenic free pure copper concentrates of 5 g Cu/L after 100 min.
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.
Rodrigues, L.; Rincón, M.; Vecino, X.; Cruz, J.; Moldes, A. Journal of surfactants and detergents Vol. 20, num. 1, p. 1-11 DOI: 10.1007/s11743-016-1897-5 Data de publicació: 2016-11-11 Article en revista
Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.