Water production from food processing wastewaters using integrated membrane systems: A sustainable approach

Castro-Muñoz, R., Fíla, V., Rodríguez-Romero, V. M., & Yáñez-Fernández, J. (November-December, 2017). Water production from food processing wastewaters using integrated membrane systems: A sustainable approach. Water Technology and Sciences (in English), 8(6), 129-136, DOI: 10.24850/j-tyca-2017-06-09. This scientific note reviews current approaches for using membrane technology to treat wastewater from food processing, for example, as a means to produce water by recovering components with high added value. In addition, with regard to the availability of wastewater, processes that contain membranes have been shown to be advantageous in terms of treating waste, recovering solutes, and producing water. With regard to the latter, processes that contain membranes can be considered to be a sustainable methodology given the valorization of waste. Lastly, this note provides a brief general view emphasizing a real need to apply membrane technology in the food industry, and indicates that its application is undoubtedly to come

Kinetic analysis of N2O decomposition over calcined hydrotalcites

Kinetics of N2O decomposition over catalyst prepared by calcination of Co–Mn hydrotalcite was examined in integral fixed-bed reactor (V/w = 12-961g(cat)(-1) h(-1)) at various N2O and O2 initial partial pressure at temperature range of 330–450 °C. Kinetic data were evaluated by linear and non-linear regression method, 15 kinetic expressions were tested. Based on the obtained results a redox model of N2O decomposition was proposed. At low pressures of O2, adsorbed oxygen is formed by the N2O decomposition; the N2O chemisorption is considered as the rate-determining step. On the contrary, at high O2 pressure it could be assumed that adsorbed oxygen species appear as a result of O2 adsorption and the Eley–Rideal mechanism is the rate determining. N2O decomposition is well described by the 1st rate law at N2O and O2 concentrations typical for waste gases

Progress on Incorporating Zeolites in Matrimid®5218 Mixed Matrix Membranes towards Gas Separation

Membranes, as perm-selective barriers, have been widely applied for gas separation applications. Since some time ago, pure polymers have been used mainly for the preparation of membranes, considering different kinds of polymers for such preparation. At this point, polyimides (e.g., Matrimid®5218) are probably one of the most considered polymers for this purpose. However, the limitation on the performance relationship of polymeric membranes has promoted their enhancement through the incorporation of different inorganic materials (e.g., zeolites) into their matrix. Therefore, the aim of this work is to provide an overview about the progress of zeolite embedding in Matrimid®5218, aiming at the preparation of mixed matrix membranes for gas separation. Particular attention is paid to the relevant experimental results and current findings. Finally, we describe the prospects and future trends in the field

Removal of Ibuprofen from Water by Different Types Membranes

Ibuprofen separation from water by adsorption and pertraction processes has been studied, comparing 16 different membranes. Tailor-made membranes based on Matrimid, Ultem, and diaminobenzene/diaminobenzoic acid with various contents of zeolite and graphene oxide, have been compared to the commercial polystyrene, polypropylene, and polydimethylsiloxane polymeric membranes. Experimental results revealed lower ibuprofen adsorption onto commercial membranes than onto tailor-made membranes (10–15% compared to 50–70%). However, the mechanical stability of commercial membranes allowed the pertraction process application, which displayed a superior quantity of ibuprofen eliminated. Additionally, the saturation of the best-performing commercial membrane, polydimethylsiloxane, was notably prevented by atomic layer deposition of (3-aminopropyl)triethoxysilane

Graphene oxide – Filled polyimide membranes in pervaporative separation of azeotropic methanol–MTBE mixtures

Graphene oxide (GO)-polyimide mixed matrix membranes (MMMs) were produced using chloroform by solvent evaporation. These membranes have been used, for the first time, in pervaporation (PV) for the separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixtures (14.3 and 85.7%, respectively). The effect of GO loading in the PV process was investigated. The PV experiments were carried out at different feed operating temperatures (25–45 °C). Furthermore, an analysis of the PV process through the Arrhenius relationship has been given. The feed temperature (in the range of 25–45 °C) affected the permeation of both components producing an increase in total permeate flux; however, separation factor was compromised. Indeed, the best permeate fluxes (ca. 0.091 kg m−2 h−1) of the MMMs (4 wt% GO) were found at 45 °C, while the best separation factor (α = 28) was found at 1 wt% GO at 25 °C. In addition, the membranes were characterized by TGA, SEM, DSC, solvent uptake and mechanical test (Young’s modulus). Finally, the performance of the GO-polyimide membranes was compared with other polymeric and MMMs membranes at the azeotropic conditions.R. Castro-Muñoz acknowledges the European Commission - Education, Audiovisual and Culture Executive Agency (EACEA) for his PhD scholarship under the program: Erasmus Mundus Doctorate in Membrane Engineering – EUDIME (FPA No 2011-0014, Edition V, http:/eudime.unical.it). This work was partially supported by the Operational Program Prague – Competitiveness (CZ.2.16/3.1.00/24501) and the “National Program of Sustainability“ (NPU I LO1613) MSMT-43760/2015. Financial support from the Spanish MINECO and FEDER (MAT2016-77290-R), the Aragón Government (T43-17R) and the ESF is also gratefully acknowledged.Peer reviewe

Molecular simulation of poly(VDF-HFP) copolymer with imidazolium-based ionic liquid as an effective medium for biogas separation

The embedding of ionic liquids (ILs) into the polymer membrane matrix affects the morphology and properties of the material. Due to the unique nature of ILs, including high thermal stability and the ability to selectively absorb various gases, polymer-IL systems generally exhibit improved separation properties. In this work, the CO2/CH4 separation properties of poly (vinylidene fluoride-co-hexafluoropropylene)) (poly (VDF-HFP)) with different amounts of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([EMIM] [TFSI]) were simulated by classical molecular dynamics (MD). MD simulations were per-formed using the GROMACS program with an AMBER force field for various polymer chain lengths (8, 10 and 12 mer) and different IL concentrations (0, 20, 40, 60 and 80 wt%) in the polymer. While the increased affinity of CO2 for the membrane containing a high concentration of IL was observed, the effect of IL on the affinity of CH4 was found to be negligible. A benefit of understanding the mechanism of gas absorption in polymeric-IL systems and revealing the interactions of gas molecules with IL and polymer molecules at the molecular level indicates the potential of MD simulation for understanding processes in membrane gas separations.Web of Science366art. no. 12028

High-pressure CO2/CH4 separation of Zr-MOFs based mixed matrix membranes

The gas separation properties of 6FDA-DAM mixed matrix membranes (MMMs) with three types of zirconium-based metal organic framework nanoparticles (MOF NPs, ca. 40 nm) have been investigated up to 20 bar. Both NPs preparation and MMMs development were presented in an earlier publication that reported outstanding CO2/CH4 separation performances (50:50 vol% CO2/CH4 feed at 2 bar pressure difference, 35 °C) and this subsequent study is to demonstrate its usefulness to the natural gas separation application. In the current work, CO2/CH4 separation has been investigated at high pressure (2–20 bar feed pressure) with different CO2 content in the feed (10–50 vol%) in the temperature range 35–55 °C. Moreover, the plasticization, competitive sorption effects, and separation of the acid gas hydrogen sulfide (H2S) have been investigated in a ternary feed mixture of CO2:H2S:CH4 (vol% ratio of 30:5:65) at 20 bar and 35 °C. The incorporation of the Zr-MOFs in 6FDA-DAM enhances both CO2 permeability and CO2/CH4 selectivity of this polymer. These MMMs exhibit high stability under separation conditions relevant to an actual natural gas sweetening process. The presence of H2S does not induce plasticization but increases the total acid gas permeability, acid gas/CH4 selectivity and only causes reversible competitive sorption. The overall study suggests a large potential for 6FDA-DAM Zr-MOF MMMs to be applied in natural gas sweetening, with good performance and stability under the relevant process conditions.The research leading to these results has received funding from ECCSEL (Grant Agreement no. 675206, European Union’s Horizon 2020 research and innovation programme). The authors also acknowledge the financial support of EACEA/European Commission, within the “Erasmus Mundus Doctorate in Membrane Engineering – EUDIME” (ERASMUS MUNDUS Programme 2009-2013, FPA n. 2011-0014, SGA n. 2012-1719), the Spanish Ministry of Economy and Competitiveness (MINECO), FEDER (MAT2016-77290-R), the European Social Fund and the Aragón Government (DGA, T05). Also the Operational Programme Prague–Competitiveness (CZ.2.16/3.1.00/24501) and National Program of Sustainability (NPU I LO1613) MSMT-43760/2015.Peer reviewe