In recent decades, mixed matrix membranes (MMMs) have attracted considerable interest in research laboratories worldwide, motivated by the gap between the growing interest in developing novel mixed ...matrix membranes by various research groups and the lack of large-scale implementation. This Special Issue contains six publications dealing with the current opportunities and challenges of mixed matrix membranes development and applications as solutions for the environmental and health challenges of 21st century society.
CO2 electroreduction has high potential to combine carbon capture utilization and energy storage from renewable sources. The key challenge is the construction of highly efficient electrodes giving ...optimal CO2 conversion to high‐value products. In this regard, research on electrode structures remains as an important task to face. Despite the advancements in gas diffusion electrodes (GDEs) to facilitate CO2 transfer and electrode efficiency, the catalyst is still vulnerable to be swept by the gas and liquid electrolyte, reducing the stability. We report the fabrication of novel membrane‐coated electrodes (MCEs), by coating an anion exchange membrane over a copper (Cu) : chitosan (CS) catalyst layer onto the carbon paper. CS and poly(vinyl) alcohol (PVA) were chosen for membrane preparation and catalyst binder, where Cu was embedded in the polymer matrix as nanoparticles or ion‐exchanged in a layered stannosilicate or zeolite Y, to improve their hydrophilic, conductive, mechanical, and environmentally‐friendly properties considered relevant to the sustainability of the electrode fabrication and performance. The intimate connection between the CS : PVA polymer membrane over‐layer and the CS/Cu catalytic layer protects the MCEs from material losses, enhancing the CO2 conversion to methanol, even in high alkaline medium. A maximum Faraday Efficiency to methanol of 68.05 % was achieved for the 10CuY/CS : PVA membrane over‐layer.
Put your coat on: Membrane‐coated electrodes have been prepared by coating the electrode with a mixed matrix layer of chitosan and polyvinyl alcohol with non‐toxic inorganic fillers; their performance in CO2 electroreduction to methanol in alkaline media is shown.
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► CO oxidation using the metal–organic framework HKUST-1 and Ce/HKUST-1. ► Slow segregation of active 5–15nm CuO particles upon MOF collapse. ► Synthesis of the highly active CuO–Ce2O ...nanoparticle catalyst. ► Effective route to immobilize nanoparticles in a monolith reactor.
The oxidation of carbon monoxide using the metal organic framework (MOF) HKUST-1 is studied. Catalytic results and characterizations by XRD, TEM, H2-TPR, SEM and LRS show that HKUST-1 itself is not effective in CO oxidation, but is activated in the reaction atmosphere segregating active 5–15nm CuO particles upon the collapse of the MOF structure. Furthermore, the microporous structure of HKUST-1 is effective to disperse Ce precursors which, upon activation, allow the synthesis of a mixture of CuO and CeO2 nanoparticles in intimate contact. These nanoparticles present a very high activity in CO oxidation. It is shown that this synthesis route employing HKUST-1 as a matrix is useful to immobilize CuO–Ce2O nanoparticles in a monolithic reactor, while keeping a high catalytic activity.
Infection caused by Streptococcus pneumoniae, mainly invasive pneumococcal disease (IPD) and pneumococcal pneumonia (PP), are a major public health problem worldwide. This study investigated ...population-based incidence and risk of PP among Catalonian persons ≥ 50 years-old with and without specific underlying conditions/comorbidities, examining the influence of single and multi-comorbidities in the risk of suffering PP.
Population-based cohort study involving 2,059,645 persons ≥ 50 years-old in Catalonia, Spain, who were retrospectively followed between 01/01/2017-31/12/2018. The Catalonian information system for development of research in primary care (SIDIAP) was used to establish baseline characteristics of the cohort (comorbidities/underlying conditions), and PP cases were collected from discharge codes (ICD-10: J13) of the 68 referral Catalonian hospitals.
Global incidence rate (IR) was 90.7 PP cases per 100,000 person-years, with a 7.6% (272/3592) case-fatality rate (CFR). Maximum IRs emerged among persons with history of previous IPD or all-cause pneumonia, followed by haematological neoplasia (475.0), HIV-infection (423.7), renal disease (384.9), chronic respiratory disease (314.7), liver disease (232.5), heart disease (221.4), alcoholism (204.8), solid cancer (186.2) and diabetes (159.6). IRs were 42.1, 89.9, 201.1, 350.9, 594.3 and 761.2 in persons with 0, 1, 2, 3, 4 and ≥ 5 comorbidities, respectively. In multivariable analyses, HIV-infection (hazard ratio HR: 5.16; 95% CI: 3.57-7.46), prior all-cause pneumonia (HR: 3.96; 95% CI: 3.45-4.55), haematological neoplasia (HR: 2.71; 95% CI: 2.06-3.57), chronic respiratory disease (HR: 2.66; 95% CI: 2.47-2.86) and prior IPD (HR: 2.56; 95% CI: 2.03-3.24) were major predictors for PP.
Apart of increasing age and immunocompromising conditions (classically recognised as high-risk conditions), history of prior IPD/pneumonia, presence of chronic pulmonary/respiratory disease and/or co-existing multi-comorbidity (i.e., two or more underlying conditions) are major risk factors for PP in adults, with an excess risk near to immunocompromised subjects. Redefining risk categories for PP, including all the above-mentioned conditions into the high-risk category, could be necessary to improve prevention strategies in middle-aged and older adults.
Alternative materials are needed to tackle the sustainability of membrane fabrication in light of the circular economy, so that membrane technology keeps playing a role as sustainable technology in ...CO2 separation processes. In this work, chitosan (CS)-based mixed matrix thin layers have been coated onto commercial polyethersulfone (PES) supports. The CS matrix was loaded by non-toxic 1-Ethyl-3-methylimidazolium acetate ionic liquid (IL) and/or laminar nanoporous AM-4 and UZAR-S3 silicates prepared without costly organic surfactants to improve CO2 permselectivity and mechanical robustness. The CO2/CH4 separation behavior of these membranes was evaluated experimentally at different feed gas composition (CO2/CH4 feed mixture from 20:80 to 70:30%), covering different separation applications associated with this separation. A cross-flow membrane cell model built using Aspen Custom Modeler was used to validate the process performance and relate the membrane properties with the target objectives of CO2 and CH4 recovery and purity in the permeate and retentate streams, respectively. The purely organic IL-CS and mixed matrix AM-4:IL-CS composite membranes showed the most promising results in terms of CO2 and CH4 purity and recovery. This is correlated with their higher hydrophilicity and CO2 adsorption and lower swelling degree, i.e., mechanical robustness, than UZAR-S3 loaded composite membranes. The purity and recovery of the 10 wt.% AM-4:IL-CS/PES composite membrane were close or even surpassed those of the hydrophobic commercial membrane used as reference. This work provides scope for membranes fabricated from renewable or biodegradable polymers and non-toxic fillers that show at least comparable CO2/CH4 separation as existing membranes, as well as the simultaneous feedback on membrane development by the simultaneous correlation of the process requirements with the membrane properties to achieve those process targets.
The continuously increasing demand of lactic acid opens a window for the integration of membrane technology in the dairy industry, improving the sustainability by avoiding the use of large amounts of ...chemicals and waste generation. Lactic acid recovery from fermentation broth without precipitation has been studied by numerous processes. In this work, a commercial membrane with high lactose rejection and a moderate lactic acid rejection, enabling a permselectivity up to 40%, is sought to perform the simultaneous removal of lactic acid and lactose separation from the acidified sweet whey from mozzarella cheese production in a single stage. The AFC30 membrane of the thin film composite nanofiltration (NF) type was selected because of its high negative charge, low isoelectric point, and divalent ion rejection, as well as a lactose rejection higher than 98% and a lactic acid rejection lower than 37%, at pH 3.5, to minimize the need of additional separation steps. The experimental lactic acid rejection was evaluated at varying feed concentration, pressure, temperature, and flow rate. As the dissociation degree of lactic acid is negligible in industrially simulated conditions, the performance of this NF membrane was validated by the irreversible thermodynamic Kedem-Katchalsky and Spiegler-Kedem models, with the best prediction in the latter case, with the parameter values: Lp = 3.24 ± 0.87 L × m−2 × h−1 × bar−1 and = 15.06 ± 3.17 L × m−2 × h−1, and σ = 0.45 ± 0.03. The results obtained in this work open the way for the up-scaling of membrane technology on the valorization of dairy effluents by simplifying the operation process and the model prediction and the choice of the membrane.
Membrane technology is a simple and energy-conservative separation option that is considered to be a green alternative for CO2 capture processes. However, commercially available membranes still face ...challenges regarding water and chemical resistance. In this study, the effect of water and organic contaminants in the feed stream on the CO2/CH4 separation performance is evaluated as a function of the hydrophilic and permselective features of the top layer of the membrane. The membranes were a commercial hydrophobic membrane with a polydimethylsiloxane (PDMS) top layer (Sulzer Chemtech) and a hydrophilic flat composite membrane with a hydrophilic emimac ionic liquid–chitosan (IL–CS) thin layer on a commercial polyethersulfone (PES) support developed in our laboratory. Both membranes were immersed in NaOH 1M solutions and washed thoroughly before characterization. The CO2 permeance was similar for both NaOH-treated membranes in the whole range of feed concentration (up to 250 GPU). The presence of water vapor and organic impurities of the feed gas largely affects the gas permeance through the hydrophobic PDMS membrane, while the behavior of the hydrophilic IL–CS/PES membranes is scarcely affected. The effects of the interaction of the contaminants in the membrane selective layer are being further evaluated.
•The surface modification method of new and re-used polyamide RO membranes and the characterization of their fouling resistance was characterized.•Surface modification was based on chitosan: ...polyvinyl alcohol mixed matrix membranes with layered fillers.•The modified membranes showed no significant loss of water and the reversibility of the fouling by simple cleaning procedures.•By means of a simple sustainable surface modification of the membrane structure, it is possible to increase the useful lifetime of thin film composite membranes.
This work aims at studying the potential of modifying the surface of used polyamide (PA) reverse osmosis (RO) commercial membranes by coatings made of renewable and biodegradable polymers, chitosan (CS) and polyvinyl alcohol (PVA), filled with Cu-ion-exchange layered AM-4 titanosilicate and UZAR-S3 stannosilicate to provide antifouling properties and enlarging life time of thin-film composite (TFC) membranes. The water permeation and fouling ratios were evaluated as a function of active layer material in the presence of model organic (BSA) and inorganic (NaCl) foulants. The mixed matrix membrane (MMM) coatings added on the active surface of the PA commercial membranes generally decreased the flux decline and increased the permeate flow recovery rate. The CS:PVA based coatings promote the reversible and not the irreversible fouling, especially CuAM-4CS:PVA. Beside, ATR-FTIR confirms the reversible nature of the BSA fouling and the irreversible nature of the NaCl fouling. These results may in the future open the possibility of renewing the useful lifetime of commercial RO membranes by a simple coating method in the light of the circular economy.
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•Benefits from pneumococcal vaccination in adults are uncertain at present.•In Catalonia, in 2017–18, pneumococcal disease burden in adults remains considerable.•Clinical effectiveness of ...PCV13/PPsV23 has not emerged after free PCV13 for children.
At present, because of indirect effects derived from routine childhood immunisation, clinical benefits vaccinating adults with the 23-valent pneumococcal polysaccharide vaccine (PPsV23) and/or the 13-valent pneumococcal conjugate vaccine (PCV13) are uncertain. This study investigated clinical effectiveness for both PPsV23/PCV13 in preventing pneumonia among Catalonian adults during an earlier 2-year period post-PCV13 free (publicly funded) approval for infants.
We conducted a Population-based cohort study involving 2,059,645 adults ≥ 50 years in Catalonia, Spain, who were followed between 01/01/2017–31/12/2018. Primary outcomes were hospitalisation from pneumococcal pneumonia (PP) or all-cause pneumonia (ACP) and main explanatory variable was PCV13/PPsV23 vaccination status. Cox regression models were used to estimate vaccination effectiveness adjusted by age/sex and underlying-risk conditions.
Cohort members were followed for 3,958,528 person-years (32,328 PCV13-vaccinated, 1,532,186 PPsV23-vaccinated), observing 3592 PP (131 in PCV13-vaccinated vs 2476 in PPsV23-vaccinated) and 24,136 ACP (876 in PCV13-vaccinated vs 17,550 in PPsV23-vaccinated). Incidence rates (per 100,000 person-years) were 90.7 for PP (394.2 in PCV13-vaccinated vs 161.6 in PPsV23-vaccinated) and 609.7 for ACP (2636.3 in PCV13-vaccinated vs 1145.4 in PPsV23-vaccinated). The PCV13 was associated with an increased risk of PP (hazard ratio HR: 1.24; 95% CI: 1.00–1.52; p = 0.046) and ACP (HR: 1.38; 95% CI: 1.28–1.49; p < 0.001) whereas the PPsV23 did not alter the risk of PP (HR: 1.07; 95% CI: 0.98–1.18; p = 0.153) and slightly increased the risk of ACP (HR: 1.14; 95% CI: 1.10–1.18; p < 0.001). In supplementary analyses focused on at-risk individuals (i.e., elderly persons, immunocompromissing and other chronic illnesses) protective effects of vaccination did not emerge either.
Data does not support clinical benefits from pneumococcal vaccination (nor PCV13 neither PPsV23) against pneumonia among Catalonian middle-aged and older adults in the current era of universal PCV13 childhood immunisation in our setting. New extended valency PCVs are greatly needed.
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