Ocean salinity observations with SMOS mission

The purpose of this paper is to present the capabilities of SMOS (Soil Moisture and Ocean Salinity mission) for the global mapping of ocean salinity from space. SMOS has been selected by the European Space Agency as the second Earth Explorer Opportunity with a launch date in June 2005. The sensor embarked on SMOS is MIRAS, a Microwave Imaging Radiometer with Aperture Synthesis. MIRAS works at L-band, in the two-polarisations, and has full polarimetric capability. The measurement of sea surface salinity (SSS) is one of the challenges of SMOS. This paper presents first the scientific requirements for a number of oceanographic applications. The scientific requirements are then translated into instrument accuracy, sensitivity, stability and spatial resolution. Major sources of error in the retrieval of ocean salinity will be addressed through an experimental campaign which is described.Peer ReviewedPostprint (published version

Fenton coupled with nanofiltration for elimination of Bisphenol A

Bisphenol A (BPA) is a typical Endocrine Disrupting Chemical (EDC), which is potentially harmful during wastewater reclamation. In this study, its degradation during Fenton's process under different operational conditions was investigated in combination with subsequent nanofiltration of low concentration remnant BPA and compounds derived from oxidation. The results indicate that BPA could be degraded efficiently in aqueous phase by Fenton, even at very low hydrogen peroxide doses. The treatment of up to 300 mg/L solutions of BPA with Fenton liquor at optimal conditions resulted in its complete removal in less than 2 min. The optimal conditions were found to be pH, = 3, H2O2/BPA = 020 and Fe2+/BPA = 0.012. Five NF polymeric membranes having different properties were used for the nanofiltration of treated and non-treated solutions. The nanofiltration of BPA solutions showed that rejection is related to adsorption ability of BPA on the membrane and size exclusion mechanism. In the nanofiltration of the effluent after Fenton oxidation, high TOC, COD, colour and Fe2+ (>77%) removal were achieved, although significant membrane fouling was also observed. The normalised water flux after membrane flushing with water was lower than 60% in almost all used membranes, which indicates significant non-easily removable fouling. (C) 2014 Elsevier B.V. All rights reserved.Peer ReviewedPostprint (author’s final draft

Flexible semi-amorphous carbon nitride films with outstanding electrochemical stability derived from soluble polymeric precursors

Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s10853-022-06906-5.Uniform flexible carbon nitride coatings have been synthesized by means of annealing of films, fabricated from soluble triazine-based polymeric precursors. The coatings exhibit fascinating electrochemical stability and drastically increase the capacitance of coated carbon cloth electrodes. Following the analogue with turbostratic carbons, typically produced by means of polymeric precursors pyrolysis, we demonstrate that annealing of dried nitrogen-rich polymeric films results in coatings, composed by nearly equal atomic quantities of carbon and nitrogen, according to elemental analysis, and exhibiting noticeable mechanical robustness. X-ray difffraction patterns and infrared spectra of the materials allow to characterize them as partially amorphous carbon nitride with presumably heptazinic structure. Annealed films exhibit extrinsic semiconducting behavior with optical bandgaps in the range from 1.71 to 1.99 eV and fairly good conductivity. The outstanding long-term electrochemical stability of annealed films makes them competitive with pyrolytic carbon, while much lower annealing temperatures allow preparation of nanocomposites with various particles. The precursor polymers were obtained by self-condensation of 2-amino-4,6-dichloro-1,3,5-triazine and condensation of cyanuric chloride with 5-aminotetrazole and 3-amino-1,2,4-triazole-5-carboxylic acid, respectively, in N,N-dimethylacetamide. The polymers contain mainly C–N skeletal bonds and can therefore be viewed as ‘‘extension’’ of typical carbon nitride precursors, like melamine or dicyandiamide, to polymeric structure.Open Access funding provided thanks to the CRUECSIC agreement with Springer Nature. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 713679 and by the Universitat Rovira i Virgili (URV), contract 2017MFP-COFUND-18. Funding for this research was provided by Ministerio de Ciencia, Innovacio´n y Universidades, the Agencia Estatal de Investigacio´n (AEI) and the European Regional Development Fund (ERDF), project RTI2018-096467- B-I00. The authors research group is recognized by the Comissionat per a Universitats i Recerca, DIUE de la Generalitat de Catalunya (2017 SGR 396), and supported by the Universitat Rovira i Virgili (2019PFR-URV-33). This paper has been possible with the support of the Universitat Rovira i Virgili (URV) and Banco Santander.Postprint (published version

Supported liquid membranes for the removal of pharmaceuticals from aqueous solutions

In the following study, the extraction of three pharmaceutical compounds: Diclofenac (DCF), ibuprofen (IBP), and carbamazepine (CBZ) by liquid-liquid extraction and their transport by supported liquid membrane (SLM) using different commercial extractants (Cyanex 923 (Cy923), trioctylamine (TOA), tributylphosphate (TBP), and Versatic Acid 10 (neodecanoic acid)) were evaluated. Cy923 was demonstrated to be an efficient extractant for diclofenac and ibuprofen removal through a facil- itated transport mechanism from the aqueous feed phase to the aqueous stripping phase using hydroxide ions as stripping agent. Around 80 % of these pharmaceuticals were extracted in 4 h with 10 % of Cy923 and without extreme alteration in the pH. As for carbamazepine, the stripping conditions were achieved with 10 % of Versatic Acid 10. Variation of concentration of different extractants indicates that a higher transport of diclofenac can be obtained by using 40 % of Cy923. In addition, two commercial polymeric supports (PTFE and PVDF) were compared for the selected operational conditions. Finally, the lifetime of the membrane was extended by soaking the polymeric material in the organic solution under vacuum for 24 h and compared with the membrane pre- pared with an ultrasound-assisted method. Supported liquid membranes present many advantages and can easily be manipulated and integrated for the treatment of persistent pharmaceutical contaminants from water.This project has been supported by the grant RTI2018-096467-B-I00 funded by MCIN/AEI/10.PK039/501100011033 and “ERDF A way of making Europe”. The authors research group is recognized by the Comissionat per a Universitats i Recerca, DIUE de la Generalitat de Catalunya (2017 SGR 396), and supported by the Universitat Rovira i Virgili (2021PFR-URV-87) and Marti Franques grant 2019PMF-PIPF-81.Peer ReviewedPostprint (published version

Compact tubular carbon-based membrane bioreactors for the anaerobic decolorization of azo dyes

This research investigates a highly efficient compact tubular ceramic-supported carbon-based membrane reactor integrated with anaerobic biodegradation to decolorize the azo dyes. Two carbon-based membranes, produced using Matrimid 5218 polyimide and graphene oxide solutions, are evaluated for the comparative color removal of three structurally different azo dyes, Acid Orange 7 (AO7), Reactive Black 5 (RB5), and Direct Blue 71 (DB71). Based on FESEM microscopic images, the average pore size of the tubular ceramic-supported carbonized membrane (TCSCM) was approximately 25 nm, while for the tubular ceramic-supported graphene oxide membrane (TCSGOM), it was 12 nm. Additionally, TCSCM had a thinner layer at only 1.10 µm, while TCSGOM was slightly thicker at 2.11 µm. These features influenced the permeate flux of the membrane, in which the TCSGOM exhibited lower permeate flux (18.2 L·m-2·h-1) than the TCSCM (45.6 L·m-2·h-1). However, the anaerobic decolorization results indicated that the TCSGOM bioreactor (B-TCSGOM) was more efficient and effective at removing color from all dye solutions than the TCSCM bioreactor (B-TCSCM) over a wide range of feed concentrations. In both reactors, the highest decolorization was achieved at low feed concentration (50 mg·L-1), and removal was 94 % for AO7, 90 % for RB5, and 88 % for DB71 in B-TCSGOM, whereas 88 %, 85 %, and 69 %, respectively, in B-TCSCM. These suggest that the robust conductive nanoporous surface of B-TCSGOM makes it more effective at removing different azo dye solutions from wastewater.This project has been supported by the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No. 713679 and by the Universitat Rovira i Virgili (URV), contract 2017MFP-COFUND-18. This article was possible thanks to the grants RTI2018-096467-B-I00 and PID2021-126895OB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and “ERDF A way of making Europe”. The authors research group is recognized by the Comissionat per a Universitats i Recerca, DIUE de la Generalitat de Catalunya (2017 SGR 396 and 2021 SGR 00200), and supported by the Universitat Rovira i Virgili (2021PFR-URV-87).Peer ReviewedPostprint (published version

Ceramic-supported graphene oxide membrane bioreactor for the anaerobic decolorization of azo dyes

A continuous compact membrane bioreactor consisted of ceramic-supported graphene oxide membrane (CSGoM) was implemented for the first time for anaerobic biodecolorization of monoazo Acid Orange 7 (AO7), diazo Reactive Black 5 (RB5), and triazo Direct Blue 71 (DB71) solutions, showing excellent decolorization potential. The membrane was prepared by vacuum filtration of various graphene oxide solutions using a UF ceramic flat element. The decolorization efficiency of the CSGoM bioreactor, made from 1 mg·mL-1 of GO solution (B-CSGoM-1), was investigated for several structurally distinct azo dyes, initial feed concentrations, and permeate fluxes. Maximum color removal was achieved under low feed concentration (50 mg·L-1) and permeate flux (0.05 L·m-2·h-1), reaching 99% for AO7, 96% RB5, and 92% for DB71. At this low permeate flux, the biodecolorization was stable for all azo dye solutions irrespective of the feed concentration. In a subsequent experiment under higher feed concentration and permeate flux (100 mg·L-1 and 0.10 L·m-2·h-1), the decolorization slightly fell to 93%, 85%, and 81% for monoazo, diazo, and triazo solutions, respectively. The existence of anaerobic bacteria (Geobacter and Pseudomonas guangdongensis) in the B-CSGoM-1 biofilm confirms that they could perform efficient biodegradation of azo dye molecules in association with the graphene oxide membrane.This project has been supported by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska- Curie grant agreement No. 713679 and by the Universitat Rovira i Virgili (URV), contract 2017MFP-COFUND-18. This article was possible thanks to the grant RTI2018-096467-B-I00 funded by MCIN/AEI/10 .13039/501100011033 and “ERDF A way of making Europe”. The au- thors research group is recognized by the Comissionat per a Universitats i Recerca, DIUE de la Generalitat de Catalunya (2017 SGR 396), and supported by the Universitat Rovira i Virgili (2019PFR-URV-33). We would like to thank Dr. Constantí for her contribution to the bacterial community characterization.Peer ReviewedPostprint (published version

Biofilm model development and process analysis of anaerobic bio-digestion of azo dyes

Ceramic-supported graphene oxide membrane bioreactors have already shown their potential for the anaerobic decolorization of wastewater containing azo dyes. The primary goal of this investigation was to develop a mathematical model that would be able to describe the steady-state behavior of this biodegradation process. The developed model was calibrated and validated using independent experimental data sets with various dye structure, feed concentration, hydraulic retention time (HRT), and support materials on which the biofilm was grown. The calibrated and validated model was used to analyze the intrinsic mechanism of the process and the main finding was that hydrolysis is the rate limiting step. Hydrolysis rate constant is decreased with increasing the complexity of the dye structure. Support materials with high electron transfer capacity increased the biofilm activity, therefore, increased the hydrolysis rate constant. Acetate concentration, used as an external carbon source, improved the dye removal efficiency. However, acetate to dye ratio did not have a direct relation to dye removal efficiency. Higher hydraulic retention time (HRT) increased the contact time between dye molecules and biofilm and enhanced the dye removal efficiency, too. However, it is essential to impose the right balance between HRT and external carbon sources to make the process feasible.This project has been supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 713679 and by the Universitat Rovira i Virgili (URV), contract 2017MFP-COFUND-18. This article was possible thanks to the grant RTI2018-096467-B-I00 funded by MCIN/AEI/10.13039/ 501100011033 and “ERDF A way of making Europe”. The authors research group is recognized by the Comissionat per a Universitats i Recerca, DIUE de la Generalitat de Catalunya (2017 SGR 396), and supported by the Universitat Rovira i Virgili (2021PFR-URV-87).Peer ReviewedPostprint (published version

Ocean salinity observations with SMOS mission

The purpose of this paper is to present the capabilities of SMOS (Soil Moisture and Ocean Salinity mission) for the global mapping of ocean salinity from space. SMOS has been selected by the European Space Agency as the second Earth Explorer Opportunity with a launch date in June 2005. The sensor embarked on SMOS is MIRAS, a Microwave Imaging Radiometer with Aperture Synthesis. MIRAS works at L-band, in the two-polarisations, and has full polarimetric capability. The measurement of sea surface salinity (SSS) is one of the challenges of SMOS. This paper presents first the scientific requirements for a number of oceanographic applications. The scientific requirements are then translated into instrument accuracy, sensitivity, stability and spatial resolution. Major sources of error in the retrieval of ocean salinity will be addressed through an experimental campaign which is described.Peer Reviewe

Extraction and purification of hydrolytic enzymes from activated sludge

A major proportion of the organic matter contained by domestic wastewater is mainly formed by lipids, proteins and carbohydrates. In order to degrade this organic matter, microorganisms produce hydrolytic enzymes like proteases, lipases and other enzymes that cannot be produced by standard cultivation techniques, which makes its recovery of interest. In the present study protease and lipase were extracted by using magnetic stirring and ultrasound disintegration combined with different additives. It was observed that the concentration of Triton X100 has a great influence in the extraction of protease, but it has no effect in the extraction of lipase. Samples obtained after ultrasound disintegration with 0% and 2% Triton X100 were further purified by precipitation with ammonium sulphate and dialysis. These samples were frozen and lyophilized in order to recover them in powder form. The optimal process for the recovery of lipase was a combination of ultrasound treatment using 0% TX100, followed by dialysis and lyophilization. This process allowed recovering around 23 lipase units/g solid.Peer ReviewedPostprint (published version

Performance comparison of torus and magnetically-stirred reactor for the enzymatic elimination of phenol

The goal of this work is the comparison of the performances of a torus and a stirred reactor for the enzymatic elimination of phenol. High degrees of conversion were obtained in both reactors for the three initial concentrations of phenol tested. In the case of the torus reactor, around 97%, 85% and 56% of phenol conversion were obtained for initial phenol concentrations of 0.5, 1.1 mM and 1.6 mM respectively, with the optimal concentrations of hydrogen peroxide. In the case of using the magnetically-stirred vessel, the extension of the phenol elimination was around 89%, 67% and 58% for an initial phenol concentration of 0.5 mM, 1.1 mM and 1.6 mM respectively. No significative differences were observed for both reactors, nevertheless the phenol conversion that was always higher for the torus reactor. Also, the values of the initial reaction rates were always lower in the stirred reactor, suggesting that the mixing in the torus reactor is more effective. The optimal H2O2 initial concentration to achieve the highest conversion of phenol has to be a ratio equal to 1 between the phenol and the H2O2 initial molar concentration. The excess of hydrogen peroxide in the mixture inhibited the activity of the enzyme, by the conversion of the peroxidase to inactive forms, provoking a reduction of the phenol conversion