Past, present and future of membrane technology in Spain

The following review aims at analyzing the contribution of Spanish researchers to membrane science and technology, with a historical compilation of the main milestones. We used a bibliometric analysis based on the Scopus database (1960?2020) dealing with 8707 documents covering the different disciplines and subject areas where membranes are involved. Furthermore, the information has been updated to the present moment of writing this manuscript in order to include the latest research lines and the different research groups currently active in Spain, which may lead the way to the development of the field in the coming years

Comparison of capillary flow porometry (CFP) and liquid extrusion porometry (LEP) techniques for the characterization of porous and face mask membranes

Producción CientíficaThis work aims to study the characterization of several membrane filters by using capillary flow porometry (CFP) and liquid extrusion porometry (LEP) to obtain their pore size distributions (PSD) and mean pore diameters (davg). Three polymeric membranes of di erent materials namely, polyethylene (PET), cellulose nitrate (CN), and FM (face mask), and one inorganic (namely, alumina Al2O3) from ultrafiltration (UF)/microfiltration (MF) and particle separation were analyzed using a pressure constant fluid/liquid extrusion porometer, developed at institute de la filtration et techniques séparatives (IFTS). Several porosimetric fluids have been used to wet and penetrate into the porous/fiber structure. The results show the accuracy of the setup on characterizing membranes in the UF/MF range by CFP, with reasonable agreement with nominal data of the filters. Additionally, LEP extension of the equipment obtained good agreement with nominal data and the CFP results, while filters presenting a microstructure of highly interconnected pores (face mask) resulted in clear di erences in terms of resulting PSD and average sizes when CFP and LEP results are compared.Ministerio de Educación Superior, Investigación e Innovación francés - (Proyecto CIR-IFTS-2020

Fitting approach to liquid–liquid displacement porosimetry based on the log-normal pore size distribution

Producción CientíficaLiquid-liquid displacement porosimetry (LLDP) has been used to characterize several UF membranes in a wide range of molecular weight cut-offs (MWCO). A new method to convert porosimetric data into pore size distributions and related information has been developed based on assuming log-normal pore size distributions. The results of this are in good agreement with those from the customary data conversion algorithm (as derived by Grabar and Nikitine). The proposed method can also be used when a reduced number of experimental data points is available, leading to a significant reduction of data acquisition time needed to complete a reliable analysis.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Cátedra de emprendedores. Una experiencia de docencia europea y cooperación entre universidad, empresa e instituciones

In this work, the authors describe their experience in the year 2003/04 with the subject “Business Creation”. This subject was part of the activities of the Chair of Entrepreneurs of the Official Chamber of Commerce and Industry of La Rioja. This is a pioneering experience aimed at contributing to the study, research and education in the main subjects of interest for entrepreneurs (reality, problems and perspectives). The collaboration agreement has an initial term of three academic years. This paper covers the following issues: ends, objectives, teaching process, human resources and materials used, cooperation with businesses and institutions, development of the course and results obtained by the students, teachers and society

Fabrication and characterization of polyethersulfone nanocomposite membranes for the removal of endocrine disrupting micropollutants from wastewater. Mechanisms and performance

Producción CientíficaThe addition of carbon nanotubes to improves the removal and adsorption of endocrine disrupting micropollutants (bisphenol A and nonylphenol). Increasing the SWCNT (single walled carbon nanotubes) content increases removal and diminishes reversible and irreversible fouling. The isoelectric point of the SWCNT containing membranes decreases when the content of nanotubes increases with more negative charges at alkaline pH. Because, the nanotube loaded membranes are also less hydrophilic and bisphenol and nonylphenol are hydrophobous, adsorption plays a key role in the removal of micropollutants. An increase in the transmembrane applied pressure decreases the removal and more steeply for the membranes containing more SWCNT. Higher porosities, leading to higher water permeabilities, are also obtained for more loaded membranes. Too high SWCNT contents lead to a saturation and decrease of removal probably because high porosities lead to a decrease in adsorption due to both a decrease in the available surface and a sweeping action of convection through the membrane.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Effects of protonation, hydroxylamination, and hydrazination of g-C3N4 on the performance of Matrimid®/g-C3N4 membranes

Producción CientíficaOne of the challenges to continue improving polymeric membranes properties involves the development of novel chemically modified fillers, such as nitrogen-rich 2-D nanomaterials. Graphitic carbon nitride (g-C3N4) has attracted significant interest as a new class of these fillers. Protonation is known to afford it desirable functionalities to form unique architectures for various applications. In the work presented herein, doping of Matrimid® with protonated g-C3N4 to yield Matrimid®/g-C3N4 mixed matrix membranes was found to improve gas separation by enhancing the selectivity for CO2/CH4 by up to 36.9% at 0.5 wt % filler doping. With a view to further enhancing the contribution of g-C3N4 to the performance of the composite membrane, oxygen plasma and hydrazine monohydrate treatments were also assayed as alternatives to protonation. Hydroxylamination by oxygen plasma treatment increased the selectivity for CO2/CH4 by up to 52.2% (at 2 wt % doping) and that for O2/N2 by up to 26.3% (at 0.5 wt % doping). Hydrazination led to lower enhancements in CO2/CH4 separation, by up to 11.4%. This study suggests that chemically-modified g-C3N4 may hold promise as an additive for modifying the surface of Matrimid® and other membranes.European Union (project LIFE15-ENV/ES/000284)Ministerio de Asuntos Económicos y Transformación Digital (projects MAT2016-76413-C2-R1 and MAT2016-76413-C2-R2

Porosimetric characterization of polysulfone ultrafiltration membranes by image analysis and liquid–liquid displacement technique

Producción CientíficaStructural and surface properties of two commercial polysulfone ultrafiltration membranes have been evaluated by different techniques. Pore size distributions have been determined by Liquid–Liquid Displacement Porosimetry (LLDP) as well as by image analysis performed onto Field Emission Scanning Electron Microscopy (FESEM) images of the membrane surfaces. Fourier TransformInfrared Spectroscopy (FTIR) has been used to investigate membrane composition, and in particular, to obtain proper information on the presence of an additive within the membrane structure. Porosimetric results obtained by the two independent techniques compared reasonably well and the Molecular Weight Cut Off (MWCO) of the two membranes estimated from LLDP pore size distribution was found to be in good agreement with the nominal values given by manufacturers.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Flux Kinetics, Limit and Critical F 1 luxes for Low Pressure Dead-end Microfiltration. 2 The case of BSA Filtration through a Positively Charged Membrane

Producción CientíficaThe influence of the applied pressure on the flux decay mechanism during Bovine Serum Albumin (BSA) dead-end microfiltration (MF) has been investigated for a polyethersulfone, positively charged, membrane (SB-6407) from Pall®11 . BSA solutions, at pH values of 4, 5 (very close to the protein isoelectric point, IEP) and 6, were micro-filtered through the membrane at different low applied transmembrane pressures. Although filtration was done in dead-end configuration, limit fluxes appeared for all pressures and pH values studied. The concepts of (long time) limit and critical fluxes and their correlation have been clarified and analysed too. The usual blocking filtration laws have been included in a common frame and both the cases with zero or non-zero limit fluxes have been incorporated. Within this frame, the standard model, that assumes an internal pore deposition, has been included as well; although, in our case, the acting mechanism seems to be mainly the so called complete blocking. Protein adsorption has been analysed in terms of the protein-protein and protein-membrane electrostatic interactions. There is a faster flux-decay for the protein isoelectric point with a slightly slower decline in flux when there are both membrane-to-protein and protein-protein repulsion. The slowest kinetics appears for membrane-to-protein attraction with protein-protein repulsion. Moreover, adsorption is stronger, and the limit flux smaller, when the protein is attracted towards the membrane and there is protein-protein repulsion.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

MAPPING COMMUNITY INTEREST HABITATS IN THE COLUMBRETES ARCHIPELAGO, AN EXTRAORDINARY HOT SPOT OF BIODIVERSITY

The Columbretes Archipelago and their submerged surroundings are part of an unusual, Pleistocene volcanic field located in the Western Mediterranean designated as a Site of Community Importance (SCI) of the Natura 2000 Network. In the present study, 4 benthic habitats of community interest (1110, 1170, 1180 and 8330) have been identified by analyzing several sources of information. Generalized additive models (GAMs) have been used to model the potential distribution of reefs (1170) and maërl beds (1110). Our results highlight the diversity and extent of these habitats and allow comparisons to other marine SCIs of Spain. This can be attributed to the variability of the environment of this site. The Columbretes Islands combine a relatively shallow environment with volcanic structures, hydrothermalism with active degassing, current-driven sedimentary lobes and the influence of inland flows. Understanding high biodiversity spots is crucial as they offer natural laboratories to describe how ecosystems respond to the effects of global change. The knowledge obtained will be of paramount importance for the conservation of species and habitats. Furthermore, it will establish a baseline for future monitoring and assist in the development of effective management plans

HLA association with the susceptibility to anti-synthetase syndrome

Objective: To investigate the human leukocyte antigen (HLA) association with anti-synthetase syndrome (ASSD). Methods: We conducted the largest immunogenetic HLA-DRB1 and HLA-B study to date in a homogeneous cohort of 168 Caucasian patients with ASSD and 486 ethnically matched healthy controls by sequencing-based-typing. Results: A statistically significant increase of HLA-DRB1*03:01 and HLA-B*08:01 alleles in patients with ASSD compared to healthy controls was disclosed (26.2% versus 12.2%, P=1.56E-09, odds ratio-OR [95% confidence interval-CI]=2.54 [1.84-3.50] and 21.4% versus 5.5%, P=18.95E-18, OR [95% CI]=4.73 [3.18-7.05]; respectively). Additionally, HLA-DRB1*07:01 allele was significantly decreased in patients with ASSD compared to controls (9.2% versus 17.5%, P=0.0003, OR [95% CI]=0.48 [0.31-0.72]). Moreover, a statistically significant increase of HLA-DRB1*03:01 allele in anti-Jo-1 positive compared to anti-Jo-1 negative patients with ASSD was observed (31.8% versus 15.5%, P=0.001, OR [95% CI]=2.54 [1.39-4.81]). Similar findings were observed when HLA carrier frequencies were assessed. The HLA-DRB1*03:01 association with anti-Jo-1 was unrelated to smoking history. No HLA differences in patients with ASSD stratified according to the presence/absence of the most representative non-anti-Jo-1 anti-synthetase autoantibodies (anti-PL-12 and anti-PL-7), arthritis, myositis or interstitial lung disease were observed. Conclusions: Our results support the association of the HLA complex with the susceptibility to ASSD