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Membrane processes are complex systems, often comprising several physicochemical phenomena, as well as biological reactions, depending on the systems studied. Therefore, process modelling is a requirement to simulate (and predict) process and membrane performance, to infer about optimal process conditions, to assess fouling development, and ultimately, for process monitoring and control. Despite the actual dissemination of terms such as Machine Learning, the use of such computational tools to model membrane processes was regarded by many in the past as not useful from a scientific point-of-view, not contributing to the understanding of the phenomena involved. Despite the controversy, in the last 25 years, data driven, non-mechanistic modelling is being applied to describe different membrane processes and in the development of new modelling and monitoring approaches. Thus, this work aims at providing a personal perspective of the use of non-mechanistic modelling in membrane processes, reviewing the evolution supported in our own experience, gained as research group working in the field of membrane processes. Additionally, some guidelines are provided for the application of advanced mathematical tools to model membrane processes.
Claudia Galinha; João Crespo. From Black Box to Machine Learning: A Journey through Membrane Process Modelling. Membranes 2021, 11, 574 .
AMA StyleClaudia Galinha, João Crespo. From Black Box to Machine Learning: A Journey through Membrane Process Modelling. Membranes. 2021; 11 (8):574.
Chicago/Turabian StyleClaudia Galinha; João Crespo. 2021. "From Black Box to Machine Learning: A Journey through Membrane Process Modelling." Membranes 11, no. 8: 574.
Protein crystallization still remains mostly an empirical science, as the production of crystals with the required quality for X-ray analysis is dependent on the intensive screening of the best protein crystallization and crystal’s derivatization conditions. Herein, this demanding step was addressed by the development of a high-throughput and low-budget microfluidic platform consisting of an ion exchange membrane (117 Nafion® membrane) sandwiched between a channel layer (stripping phase compartment) and a wells layer (feed phase compartment) forming 75 independent micro-contactors. This microfluidic device allows for a simultaneous and independent screening of multiple protein crystallization and crystal derivatization conditions, using Hen Egg White Lysozyme (HEWL) as the model protein and Hg2+ as the derivatizing agent. This microdevice offers well-regulated crystallization and subsequent crystal derivatization processes based on the controlled transport of water and ions provided by the 117 Nafion® membrane. Diffusion coefficients of water and the derivatizing agent (Hg2+) were evaluated, showing the positive influence of the protein drop volume on the number of crystals and crystal size. This microfluidic system allowed for crystals with good structural stability and high X-ray diffraction quality and, thus, it is regarded as an efficient tool that may contribute to the enhancement of the proteins’ crystals structural resolution.
M. Polino; H. Rho; M. Pina; R. Mallada; A. Carvalho; M. Romão; Isabel Coelhoso; J. Gardeniers; J. Crespo; Carla Portugal. Protein Crystallization in a Microfluidic Contactor with Nafion®117 Membranes. Membranes 2021, 11, 549 .
AMA StyleM. Polino, H. Rho, M. Pina, R. Mallada, A. Carvalho, M. Romão, Isabel Coelhoso, J. Gardeniers, J. Crespo, Carla Portugal. Protein Crystallization in a Microfluidic Contactor with Nafion®117 Membranes. Membranes. 2021; 11 (8):549.
Chicago/Turabian StyleM. Polino; H. Rho; M. Pina; R. Mallada; A. Carvalho; M. Romão; Isabel Coelhoso; J. Gardeniers; J. Crespo; Carla Portugal. 2021. "Protein Crystallization in a Microfluidic Contactor with Nafion®117 Membranes." Membranes 11, no. 8: 549.
Corn fibre, a co-product of the starch industry, is rich in compounds with high added value, such as ferulic acid and arabinoxylans, which are released during alkaline extraction. This work aims to optimise an efficient separation method for the recovery of these two compounds from a corn fibre alkaline extract, allowing an efficient valorisation of this co-product. Ultrafiltration was selected as separation method, due to its potential to fractionate these compounds. In order to minimise the loss of membrane permeance, due to mass transfer limitations caused by the high arabinoxylan viscosity, the impact of relevant ultrafiltration operating parameters (membrane molecular weight cut-off, fluid dynamics conditions, transmembrane pressure, and operating temperature) were evaluated. A Nadir UP 150 membrane was found to be an adequate choice, allowing for an efficient separation of ferulic acid from arabinoxylans, with null rejection of ferulic acid, a high estimated rejection of arabinoxylans 98.0% ± 1.7%, and the highest permeance of all tested membranes. A response surface methodology (RSM) was used to infer the effect of ultrafiltration conditions (crossflow velocity, transmembrane pressure and operating temperature) on the rejection of ferulic acid, retention of arabinoxylans (assessed through apparent viscosity of the retentate stream), and permeance. Through mathematical modelling it was possible to determine that the best conditions are the highest operating temperature and initial crossflow velocity tested (66 °C and 1.06 m.s−1, respectively), and the lowest transmembrane pressure tested (0.7 bar).
Rita Valério; João Crespo; Claudia Galinha; Carla Brazinha. Effect of Ultrafiltration Operating Conditions for Separation of Ferulic Acid from Arabinoxylans in Corn Fibre Alkaline Extract. Sustainability 2021, 13, 4682 .
AMA StyleRita Valério, João Crespo, Claudia Galinha, Carla Brazinha. Effect of Ultrafiltration Operating Conditions for Separation of Ferulic Acid from Arabinoxylans in Corn Fibre Alkaline Extract. Sustainability. 2021; 13 (9):4682.
Chicago/Turabian StyleRita Valério; João Crespo; Claudia Galinha; Carla Brazinha. 2021. "Effect of Ultrafiltration Operating Conditions for Separation of Ferulic Acid from Arabinoxylans in Corn Fibre Alkaline Extract." Sustainability 13, no. 9: 4682.
In this study, we report the impact of the magnetic field on protein permeability through magnetic-responsive, block copolymer, nanocomposite membranes with hydrophilic and hydrophobic characters. The hydrophilic nanocomposite membranes were composed of spherical polymeric nanoparticles (NPs) synthesized through polymerization-induced self-assembly (PISA) with iron oxide NPs coated with quaternized poly(2-dimethylamino)ethyl methacrylate. The hydrophobic nanocomposite membranes were prepared via nonsolvent-induced phase separation (NIPS) containing poly (methacrylic acid) and meso-2,3-dimercaptosuccinic acid-coated superparamagnetic nanoparticles (SPNPs). The permeation experiments were carried out using bovine serum albumin (BSA) as the model solute, in the absence of the magnetic field and under permanent and cyclic magnetic field conditions OFF/ON (strategy 1) and ON/OFF (strategy 2). It was observed that the magnetic field led to a lower reduction in the permeate fluxes of magnetic-responsive membranes during BSA permeation, regardless of the magnetic field strategy used, than that obtained in the absence of the magnetic field. Nevertheless, a comparative analysis of the effect caused by the two cyclic magnetic field strategies showed that strategy 2 allowed for a lower reduction of the original permeate fluxes during BSA permeation and higher protein sieving coefficients. Overall, these novel magneto-responsive block copolymer nanocomposite membranes proved to be competent in mitigating biofouling phenomena in bioseparation processes.
Lakshmeesha Upadhyaya; Mona Semsarilar; Damien Quemener; Rodrigo Fernández-Pacheco; Gema Martinez; Isabel Coelhoso; Suzana Nunes; João Crespo; Reyes Mallada; Carla Portugal. Block Copolymer-Based Magnetic Mixed Matrix Membranes—Effect of Magnetic Field on Protein Permeation and Membrane Fouling. Membranes 2021, 11, 105 .
AMA StyleLakshmeesha Upadhyaya, Mona Semsarilar, Damien Quemener, Rodrigo Fernández-Pacheco, Gema Martinez, Isabel Coelhoso, Suzana Nunes, João Crespo, Reyes Mallada, Carla Portugal. Block Copolymer-Based Magnetic Mixed Matrix Membranes—Effect of Magnetic Field on Protein Permeation and Membrane Fouling. Membranes. 2021; 11 (2):105.
Chicago/Turabian StyleLakshmeesha Upadhyaya; Mona Semsarilar; Damien Quemener; Rodrigo Fernández-Pacheco; Gema Martinez; Isabel Coelhoso; Suzana Nunes; João Crespo; Reyes Mallada; Carla Portugal. 2021. "Block Copolymer-Based Magnetic Mixed Matrix Membranes—Effect of Magnetic Field on Protein Permeation and Membrane Fouling." Membranes 11, no. 2: 105.
Technologies for wastewater reclamation and water reuse within oil refineries have been gaining particular attention over the past decade due to legislative pressures associated with the efficient use of water resources and wastewater discharge.
Pedro D. A. Bastos; Maria António Santos; Pedro Jorge Carvalho; Svetlozar Velizarov; João G. Crespo. Pilot scale reverse osmosis refinery wastewater treatment – a techno-economical and sustainability assessment. Environmental Science: Water Research & Technology 2021, 7, 549 -561.
AMA StylePedro D. A. Bastos, Maria António Santos, Pedro Jorge Carvalho, Svetlozar Velizarov, João G. Crespo. Pilot scale reverse osmosis refinery wastewater treatment – a techno-economical and sustainability assessment. Environmental Science: Water Research & Technology. 2021; 7 (3):549-561.
Chicago/Turabian StylePedro D. A. Bastos; Maria António Santos; Pedro Jorge Carvalho; Svetlozar Velizarov; João G. Crespo. 2021. "Pilot scale reverse osmosis refinery wastewater treatment – a techno-economical and sustainability assessment." Environmental Science: Water Research & Technology 7, no. 3: 549-561.
Broad-spectrum fluoroquinolone antibiotics (ciprofloxacin and levofloxacin), carbapenem and fluoroquinolone resistance genes, as well as viral genomes, were detected in grab samples of wastewater effluents. Passive samplers, which are simpler and easier to use and provide information about the concentrations and combination of contaminants present in a certain fluid matrix over time, proved to be extremely promising devices to monitor the presence of the target antibiotics in wastewater effluents. Nanofiltration was tested with a pilot-scale unit installed at a domestic wastewater treatment facility, using a Desal 5DK membrane operated at a constant transmembrane pressure of 6 bar and 70% recovery rate. In a 24 h experimental assay, the variation of the membrane permeance was low (6.3%). High rejections of the target contaminants from the wastewater effluent were obtained by the pilot-scale treatment. Hence, nanofiltration using the Desal 5DK membrane is considered to be a promising treatment to cope with chemical and biological contaminants present in wastewater effluents.
Maria Beatriz Cristóvão; Solomon Tela; Andreia Filipa Silva; Micaela Oliveira; Andreia Bento-Silva; Maria Rosário Bronze; Maria Teresa Barreto Crespo; João Goulão Crespo; Mónica Nunes; Vanessa Jorge Pereira. Occurrence of Antibiotics, Antibiotic Resistance Genes and Viral Genomes in Wastewater Effluents and Their Treatment by a Pilot Scale Nanofiltration Unit. Membranes 2020, 11, 9 .
AMA StyleMaria Beatriz Cristóvão, Solomon Tela, Andreia Filipa Silva, Micaela Oliveira, Andreia Bento-Silva, Maria Rosário Bronze, Maria Teresa Barreto Crespo, João Goulão Crespo, Mónica Nunes, Vanessa Jorge Pereira. Occurrence of Antibiotics, Antibiotic Resistance Genes and Viral Genomes in Wastewater Effluents and Their Treatment by a Pilot Scale Nanofiltration Unit. Membranes. 2020; 11 (1):9.
Chicago/Turabian StyleMaria Beatriz Cristóvão; Solomon Tela; Andreia Filipa Silva; Micaela Oliveira; Andreia Bento-Silva; Maria Rosário Bronze; Maria Teresa Barreto Crespo; João Goulão Crespo; Mónica Nunes; Vanessa Jorge Pereira. 2020. "Occurrence of Antibiotics, Antibiotic Resistance Genes and Viral Genomes in Wastewater Effluents and Their Treatment by a Pilot Scale Nanofiltration Unit." Membranes 11, no. 1: 9.
Ionic liquids (ILs) with quaternary ammonium cations combined with biocompatible anions from renewable sources result in low-toxic, biocompatible, cost-efficient sorbent media that can efficiently capture carbon dioxide (CO2). The understanding of the equilibrium and kinetics of CO2absorption in these media is relevant for the design of new absorption processes in many application areas, such as CO2 removal from post-combustion streams, biogas refinery waste gases, or confined spaces. Here CO2absorption in an aqueous solution of cholinium lysinate IL is studied both theoretically, via mechanistic modelling, and experimentally in a membrane contactor operated in closed loop with online pH measurement and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis of discrete sampling of the circulating aqueous IL solution. It is shown that both techniques are effective tools for CO2quantification in the liquid phase. The IL yields an absorption capacity of 2.20 mol of CO2 per mole of IL for an IL concentration of 2.13 M (or 50 wt% solution). A comprehensive model of chemisorption thermodynamics and absorption dynamics is proposed and validated experimentally. It provides not only the equilibrium constants of the reversible reactions of protonation of the amine groups and bicarbonate binding and overall mass-transfer coefficient based on liquid-phase concentrations, but is also the basis for a chemometric analysis of the experimental ATR-FTIR data. The potential use of ATR-FTIR as a monitoring tool of CO2 in aqueous solutions of cholinium lysinate IL is also demonstrated.
C.F. Martins; L.A. Neves; R. Chagas; L.M. Ferreira; C.A.M. Afonso; I.M. Coelhoso; J.G. Crespo; J.Pb. Mota. Modelling CO2 absorption in aqueous solutions of cholinium lysinate ionic liquid. Chemical Engineering Journal 2020, 421, 127875 .
AMA StyleC.F. Martins, L.A. Neves, R. Chagas, L.M. Ferreira, C.A.M. Afonso, I.M. Coelhoso, J.G. Crespo, J.Pb. Mota. Modelling CO2 absorption in aqueous solutions of cholinium lysinate ionic liquid. Chemical Engineering Journal. 2020; 421 ():127875.
Chicago/Turabian StyleC.F. Martins; L.A. Neves; R. Chagas; L.M. Ferreira; C.A.M. Afonso; I.M. Coelhoso; J.G. Crespo; J.Pb. Mota. 2020. "Modelling CO2 absorption in aqueous solutions of cholinium lysinate ionic liquid." Chemical Engineering Journal 421, no. : 127875.
The objective of this work is to develop an appropriate technology for environmentally sound membrane-based purification of a tannery effluent assuring, simultaneously, the recovery of chromium, considered as the most hazardous inorganic water pollutant extensively used in leather tanning. A comparison between the permeate fluxes obtained during treatment of a synthetic tannery effluent through nanofiltration (NF270 and NF90 membranes) and reverse osmosis (BW30 and SW30) membranes was first performed. Then, a dedicated polymeric membrane was prepared by coating chitosan (cs) on a polyethersulfone (PES) microfiltration membrane (cs-PES MFO22) support. The resulting membrane was characterized by Fourier Transforms Infrared Spectroscopy Attenuated Total Reflectance (FTIR-ATR), Emission Scanning Electronic Microscopy (SEM) to confirm the process of surface modification and cross-linking of chitosan with glutaraldehyde. This membrane was found to be highly effective for chromium removal (>99%), which was more than eight times higher in reference to monovalent cations (e.g., Na+ and K+) and more than six times higher in reference to the divalent cations (Mg2+ and Ca2+) studied. The reverse osmosis permeate conforms to local Algerian regulations regarding being discharged directly into the natural environment (in this case, Reghaia Lake) or into urban sewers linked to wastewater biological treatment stations. While the SW30 membrane proved to be the most effective for purification of the tannery effluent, the chitosan modified membrane proved to be appropriate for recovery of chromium from the reverse osmosis concentrate.
Asmaa Zakmout; Fatma Sadi; Carla A. M. Portugal; João G. Crespo; Svetlozar Velizarov. Tannery Effluent Treatment by Nanofiltration, Reverse Osmosis and Chitosan Modified Membranes. Membranes 2020, 10, 378 .
AMA StyleAsmaa Zakmout, Fatma Sadi, Carla A. M. Portugal, João G. Crespo, Svetlozar Velizarov. Tannery Effluent Treatment by Nanofiltration, Reverse Osmosis and Chitosan Modified Membranes. Membranes. 2020; 10 (12):378.
Chicago/Turabian StyleAsmaa Zakmout; Fatma Sadi; Carla A. M. Portugal; João G. Crespo; Svetlozar Velizarov. 2020. "Tannery Effluent Treatment by Nanofiltration, Reverse Osmosis and Chitosan Modified Membranes." Membranes 10, no. 12: 378.
Cynara cardunculus (cardoon) leaves are a rich source of bioactive compounds, such as cynaropicrin. In this work, ethanolic pulsed ultrasound assisted extraction (EtPUAE) derived extracts obtained from cardoon leaves were purified by membrane processing and the different fractions obtained were evaluated for their biological potential. A DuraMem® 200 membrane was selected for cynaropicrin recovery and removal of carbohydrates, in a diananofiltration mode. Diananofiltration (after 5 diavolumes) followed by nanofiltration allowed for a removal of 93.0% of glucose and 95.6% of fructose, with a cynaropicrin maximum loss of 13.9%. The fractionated extract revealed a higher biological activity, when tested with a BJ5-ta human normal fibroblast cell line. An integrated process is proposed, comprising an association of EtPUAE with a fractionation by diananofiltration, assuring a pay-back period of 4.58 years, assessed through an economic evaluation.
Teresa Brás; Daniela Rosa; Ana C. Gonçalves; Andreia C. Gomes; Carla Brazinha; Luísa A. Neves; Maria F. Duarte; João G. Crespo. Fractionation of Cynara cardunculus ethanolic extracts using diananofiltration. Separation and Purification Technology 2020, 256, 117856 .
AMA StyleTeresa Brás, Daniela Rosa, Ana C. Gonçalves, Andreia C. Gomes, Carla Brazinha, Luísa A. Neves, Maria F. Duarte, João G. Crespo. Fractionation of Cynara cardunculus ethanolic extracts using diananofiltration. Separation and Purification Technology. 2020; 256 ():117856.
Chicago/Turabian StyleTeresa Brás; Daniela Rosa; Ana C. Gonçalves; Andreia C. Gomes; Carla Brazinha; Luísa A. Neves; Maria F. Duarte; João G. Crespo. 2020. "Fractionation of Cynara cardunculus ethanolic extracts using diananofiltration." Separation and Purification Technology 256, no. : 117856.
The development of efficient and clean CO2 capture technologies is a topic of utmost importance in the global environmental agenda. In this work, a wide range of analytical procedures (1H and 13C NMR, TGA, DSC, FT-IR, viscosity, density, refractive index, fluorescence anisotropy, UV–Vis) was used to investigate the properties of deep eutectic solvent (DES) composed of choline chloride and levulinic acid (ChCl:LA), conditioned to four different water activity (aw) values. Also, the impact of using the enzyme carbonic anhydrase (CA), known for its ability to reversibly convert CO2 into bicarbonate, was assessed on DES properties. The ChCl:LA-water mixtures showed to be present as a cohesive cluster up to aw = 0.753 and, above that, in a hydrated form with a free water layer that could crystalize at negative temperatures (-40 to −45 °C), suggesting anti-freezing properties of the solvent. DES were then supported in polymeric hydrophilic membranes. Based on CO2 and N2 permeabilities through these membranes, the one that contained ChCl:LA at aw = 0.216 was further studied regarding its long-term stability. This supported liquid membrane showed a consistent behavior for up to 30 repeated cycles and a stable operating behavior for transmembrane pressure differences in the range of 0.50–1.25 bar. These findings evidence the stability of supported DES membranes and the potential for CO2 capture.
Aline M. de Castro; Dala Prasavath; Juliana V. Bevilaqua; Carla A.M. Portugal; Luisa A. Neves; João G. Crespo. Role of water on deep eutectic solvents (DES) properties and gas transport performance in biocatalytic supported DES membranes. Separation and Purification Technology 2020, 255, 117763 .
AMA StyleAline M. de Castro, Dala Prasavath, Juliana V. Bevilaqua, Carla A.M. Portugal, Luisa A. Neves, João G. Crespo. Role of water on deep eutectic solvents (DES) properties and gas transport performance in biocatalytic supported DES membranes. Separation and Purification Technology. 2020; 255 ():117763.
Chicago/Turabian StyleAline M. de Castro; Dala Prasavath; Juliana V. Bevilaqua; Carla A.M. Portugal; Luisa A. Neves; João G. Crespo. 2020. "Role of water on deep eutectic solvents (DES) properties and gas transport performance in biocatalytic supported DES membranes." Separation and Purification Technology 255, no. : 117763.
The performance of anion-exchange membranes (AEMs) in Reverse Electrodialysis is hampered by both presence of multivalent ions and fouling phenomena, thus leading to reduced net power density. Therefore, we propose a monolayer surface modification procedure to functionalize Ralex-AEMs with poly(acrylic) acid (PAA) in order to (i) render a monovalent permselectivity, and (ii) minimize organic fouling. Membrane surface modification was carried out by putting heterogeneous AEMs in contact with a PAA-based aqueous solution for 24 h. The resulting modified membranes were firstly characterized by contact angle, water uptake, ion exchange capacity, fixed charge density, and swelling degree measurements, whereas their electrochemical responses were evaluated through cyclic voltammetry. Besides, their membrane electro-resistance was also studied via electrochemical impedance spectroscopy analyses. Finally, membrane permselectivity and fouling behavior in the presence of humic acid were evaluated through mass transport experiments using model NaCl containing solutions. The use of modified PAA-AEMs resulted in a significantly enhanced monovalent permselectivity (sulfate rejection improved by >35%) and membrane hydrophilicity (contact angle decreased by >15%) in comparison with the behavior of unmodified Ralex-AEMs, without compromising the membrane electro-resistance after modification, thus demonstrating the technical feasibility of the proposed membrane modification procedure. This study may therefore provide a feasible way for achieving an improved Reverse Electrodialysis process efficiency.
Ivan Merino-Garcia; Francis Kotoka; Carla A.M. Portugal; João G. Crespo; Svetlozar Velizarov. Characterization of Poly(Acrylic) Acid-Modified Heterogenous Anion Exchange Membranes with Improved Monovalent Permselectivity for RED. Membranes 2020, 10, 134 .
AMA StyleIvan Merino-Garcia, Francis Kotoka, Carla A.M. Portugal, João G. Crespo, Svetlozar Velizarov. Characterization of Poly(Acrylic) Acid-Modified Heterogenous Anion Exchange Membranes with Improved Monovalent Permselectivity for RED. Membranes. 2020; 10 (6):134.
Chicago/Turabian StyleIvan Merino-Garcia; Francis Kotoka; Carla A.M. Portugal; João G. Crespo; Svetlozar Velizarov. 2020. "Characterization of Poly(Acrylic) Acid-Modified Heterogenous Anion Exchange Membranes with Improved Monovalent Permselectivity for RED." Membranes 10, no. 6: 134.
The unprecedently high CO2 levels in the atmosphere evoke the urgent need for development of technologies for mitigation of its emissions. Among the alternatives, the biocatalytic route has been claimed as one of the most promising. In the present work, the carbonic anhydrase from bovine erythrocytes (BCA) was employed as a model enzyme for structural studies in an aqueous phase at alkaline pH, which is typical of large-scale absorption processes under operation. Circular dichroism (CD) analysis revealed a high enzymatic stability at pH 10 with a prominent decrease of the melting temperature above this value. The CO2 absorption capacity of the aqueous solutions were assessed by online monitoring of pressure decay in a stainless-steel cell, which indicated a better performance at pH 10 with a kinetic rate increase of up to 43%, as compared to non-biocatalytic conditions. Even low enzyme concentrations (0.2 mg g−1) proved to be sufficient to improve the overall CO2 capture process performance. The enzyme-enhanced approach of CO2 capture presents a high potential and should be further studied.
Aline M. De Castro; Elisabete Ferreira; Carla Portugal; Luisa A. Neves; João G. Crespo. Biocatalytic CO2 Absorption and Structural Studies of Carbonic Anhydrase under Industrially-Relevant Conditions. International Journal of Molecular Sciences 2020, 21, 2918 .
AMA StyleAline M. De Castro, Elisabete Ferreira, Carla Portugal, Luisa A. Neves, João G. Crespo. Biocatalytic CO2 Absorption and Structural Studies of Carbonic Anhydrase under Industrially-Relevant Conditions. International Journal of Molecular Sciences. 2020; 21 (8):2918.
Chicago/Turabian StyleAline M. De Castro; Elisabete Ferreira; Carla Portugal; Luisa A. Neves; João G. Crespo. 2020. "Biocatalytic CO2 Absorption and Structural Studies of Carbonic Anhydrase under Industrially-Relevant Conditions." International Journal of Molecular Sciences 21, no. 8: 2918.
In this study, conditions for ultrasound assisted extraction (UAE) of cynaropicrin from Cynara cardunculus leaves by assessing the effect of pulsed mode and different duty cycles were optimized. Pulse mode presented a reduction of 45 % on energy consumption/ g cynaropicrin extracted, comparatively to continuous mode, and a duty cycle of 25 % presented the highest kinetic rate between the duty cycles under study, with a lower number of pulse repetitions necessary to reach a steady state conditions. The extraction methodology was further optimized by response surface methodology (RSM), using a Box-Bhenken design with 3 factors (solid/liquid ratio, amplitude and temperature), and 3 levels for correlation of independent variables with the extraction yield (mg of cynaropicrin/g dry weight) and cynaropicrin concentration (mg cynaropicrin /g extract). Experimental results were fitted to a second order polynomial model, using multiple regression and analysis of variance to determine the fitness of the model. Optimal conditions were found for a solid/liquid ratio of 1/27, amplitude of 67 % and temperature of 44 °C, with a predicted value of 23.99 mg/g DW and 192.23 mg/g extract for extraction yield and cynaropicrin concentration, respectively. The predicted values fit the experimental ones, with a 95 % confidence level showing the accuracy of the model. The results obtained suggest the applicability of the UAE optimization methodologies described, for cynaropicrin extraction from Cynara cardunculus leaves, illustrating its potential application on biotechnological and agro food industries.
Teresa Brás; Ana F.C. Paulino; Luísa A. Neves; João Crespo; Maria F. Duarte. Ultrasound assisted extraction of cynaropicrin from Cynara cardunculus leaves: Optimization using the response surface methodology and the effect of pulse mode. Industrial Crops and Products 2020, 150, 112395 .
AMA StyleTeresa Brás, Ana F.C. Paulino, Luísa A. Neves, João Crespo, Maria F. Duarte. Ultrasound assisted extraction of cynaropicrin from Cynara cardunculus leaves: Optimization using the response surface methodology and the effect of pulse mode. Industrial Crops and Products. 2020; 150 ():112395.
Chicago/Turabian StyleTeresa Brás; Ana F.C. Paulino; Luísa A. Neves; João Crespo; Maria F. Duarte. 2020. "Ultrasound assisted extraction of cynaropicrin from Cynara cardunculus leaves: Optimization using the response surface methodology and the effect of pulse mode." Industrial Crops and Products 150, no. : 112395.
Technologies for water recycling within oil refineries have been gaining interest at an extensive rate due to the large volume of wastewater generated, high dependency of water and the progressive scarcity of this valuable resource. Phenols are part of a specific class of organic pollutants that have been contributing to a low-quality effluent in oil refineries due to their hazardous nature and strict environmental legislation associated. The reuse of stripped sour water within refineries is often blocked due to its rich phenolic content. This study evaluates the retention of phenols in refinery wastewater through reverse osmosis (RO) at its major source of emission, for water reclamation. The RO membrane selected exhibited rejections of up to 98% of phenols and 99% of both chemical oxygen demand (COD) and total organic carbon (TOC). Permeate quality remained intact despite flux decline caused by phenolic and hydrocarbon adsorption when the oil content, in the feed, reached 771 ppm. The effluent's low conductivity due to lack of salts led to minor osmotic pressure differences (less than 2.5 bar at a volume concentration factor of 3), therefore, showing appealing performances of reverse osmosis filtration. Characterization of all permeates obtained from cross-flow filtration experiments showed COD levels in line with water reuse quality standards for make-up water in cooling processes.
Pedro D.A. Bastos; Maria António Santos; Pedro Jorge Carvalho; João G. Crespo. Reverse osmosis performance on stripped phenolic sour water treatment – A study on the effect of oil and grease and osmotic pressure. Journal of Environmental Management 2020, 261, 110229 .
AMA StylePedro D.A. Bastos, Maria António Santos, Pedro Jorge Carvalho, João G. Crespo. Reverse osmosis performance on stripped phenolic sour water treatment – A study on the effect of oil and grease and osmotic pressure. Journal of Environmental Management. 2020; 261 ():110229.
Chicago/Turabian StylePedro D.A. Bastos; Maria António Santos; Pedro Jorge Carvalho; João G. Crespo. 2020. "Reverse osmosis performance on stripped phenolic sour water treatment – A study on the effect of oil and grease and osmotic pressure." Journal of Environmental Management 261, no. : 110229.
With the increase awareness for a healthier food regime and greener environmental processes, microalgae are being looked as a solution for a sustainable production of polyunsaturated fatty acids, such as omega-3 eicosapentaenoic acid (EPA). Nannochloropsis oceanica is an oleaginous microalga, well-known for the ability of EPA accumulation, although higher lipid productivities are still required to make the process competitive. Therefore, three cultivation parameters were tested in the present work (temperature, light cycles and nitrogen supply) in order to study the EPA profile in the polar and neutral fractions of the cells. In addition, an online monitoring tool based on a fluorescence spectroscopy technique was developed with the aim of increasing process knowledge at real time. The results of this work show that nitrogen depletion induces the highest variability in EPA accumulation in the neutral fraction (triacylglycerols). However, to increase the EPA content in the polar fraction a different strategy needs to be implemented, such as decreasing the cultivation temperature or the light available per cell. Chemometric models were developed through PCA (Principal Component Analysis) and PLS (Projection to Latent Structures), using only fluorescence spectra as inputs, enabling the monitoring of EPA in both fractions separately. High explained variance was observed (above 85%) in both fractions, with R2 above 0.81 and slopes above 0.93 for both validation and training data sets. Lower values of cross-validation and prediction errors were observed (between 0.29 and 0.49% g/gDW). The results obtained show that fluorescence spectroscopy is a powerful technique for online monitoring of non-fluorophore molecules, such as EPA, in complex process like microalgae cultivation.
Marta Sa; Narcís Ferrer-Ledo; Rene Wijffels; João Crespo; Maria Barbosa; Claudia F. Galinha. Monitoring of eicosapentaenoic acid (EPA) production in the microalgae Nannochloropsis oceanica. Algal Research 2019, 45, 101766 .
AMA StyleMarta Sa, Narcís Ferrer-Ledo, Rene Wijffels, João Crespo, Maria Barbosa, Claudia F. Galinha. Monitoring of eicosapentaenoic acid (EPA) production in the microalgae Nannochloropsis oceanica. Algal Research. 2019; 45 ():101766.
Chicago/Turabian StyleMarta Sa; Narcís Ferrer-Ledo; Rene Wijffels; João Crespo; Maria Barbosa; Claudia F. Galinha. 2019. "Monitoring of eicosapentaenoic acid (EPA) production in the microalgae Nannochloropsis oceanica." Algal Research 45, no. : 101766.
The presence of anti-cancer drugs in European surface waters appeals for the development of novel treatment processes. In this work, light emitting diodes (LEDs) that emit light at 255 nm (UV-C) and 365 nm (UV-A) wavelengths were compared in terms of their ability to degrade four anti-cancer drugs by UV and UV/TiO2 process. None of treatments tested were able to degrade cyclophosphamide and ifosfamide. Nevertheless etoposide and paclitaxel were successfully eliminated by UV-C and UV-C/TiO2. Moreover, higher energetic yields were obtained with UV-C light for the degradation of anti-cancer drugs by photocatalysis than with UV-A. The option of using this treatment to deal with pollution at the source by performing essays in synthetic urine was shown to be not adequate, as drug photocatalysis was totally inhibited by the presence of radical scavenger species present in the urine matrix.
Raphael Janssens; Beatriz M. Cristóvão; Maria R. Bronze; Joao G. Crespo; Vanessa J. Pereira; Patricia Luis. Photocatalysis Using UV-A and UV-C Light Sources for Advanced Oxidation of Anti-Cancer Drugs Spiked in Laboratory-Grade Water and Synthetic Urine. Industrial & Engineering Chemistry Research 2019, 59, 647 -653.
AMA StyleRaphael Janssens, Beatriz M. Cristóvão, Maria R. Bronze, Joao G. Crespo, Vanessa J. Pereira, Patricia Luis. Photocatalysis Using UV-A and UV-C Light Sources for Advanced Oxidation of Anti-Cancer Drugs Spiked in Laboratory-Grade Water and Synthetic Urine. Industrial & Engineering Chemistry Research. 2019; 59 (2):647-653.
Chicago/Turabian StyleRaphael Janssens; Beatriz M. Cristóvão; Maria R. Bronze; Joao G. Crespo; Vanessa J. Pereira; Patricia Luis. 2019. "Photocatalysis Using UV-A and UV-C Light Sources for Advanced Oxidation of Anti-Cancer Drugs Spiked in Laboratory-Grade Water and Synthetic Urine." Industrial & Engineering Chemistry Research 59, no. 2: 647-653.
This work described a new sustainable method for the fabrication of ceramic membranes with high photocatalytic activity, through a simple sol-gel route. The photocatalytic surfaces, prepared at low temperature and under solvent-free conditions, exhibited a narrow pore size distribution and homogeneity without cracks. These surfaces have shown a highly efficient and reproducible behavior for the degradation of methylene blue. Given their characterization results, the microfiltration photocatalytic membranes produced in this study using solvent-free conditions are expected to effectively retain microorganisms, such as bacteria and fungi that could then be inactivated by photocatalysis.
Rosa M. Huertas; Maria C. Fraga; João G. Crespo; Vanessa J. Pereira. Solvent-Free Process for the Development of Photocatalytic Membranes. Molecules 2019, 24, 4481 .
AMA StyleRosa M. Huertas, Maria C. Fraga, João G. Crespo, Vanessa J. Pereira. Solvent-Free Process for the Development of Photocatalytic Membranes. Molecules. 2019; 24 (24):4481.
Chicago/Turabian StyleRosa M. Huertas; Maria C. Fraga; João G. Crespo; Vanessa J. Pereira. 2019. "Solvent-Free Process for the Development of Photocatalytic Membranes." Molecules 24, no. 24: 4481.
When growing microalgae for biorefinery processes, a high product yield is desired. For that reason, monitoring the concentration of the desired products during growth and products induction procedure is of great interest. 2D Fluorescence spectroscopy is a fingerprinting technique, used in situ and at real time, with a high potential for online monitoring of biological systems. In this work, Dunaliella salina pigment content was monitored using fluorescence data coupled with chemometric tools. Climatic parameters were also used as input variables due to their impact on the pigments profile in outdoor cultivations. Predictive models were developed for chlorophyll content (a, b, and total) with variance captured between 50 and 90%, and R2 varying between 0.6 and 0.9 for both training and validation data sets. Total carotenoids models captured 70 to 80% of variance, and R2 between 0.7 and 0.9, for training and validation. Models for specific carotenoids (zeaxanthin, α-carotene, all-trans-β-carotene, and 9-cis-β-carotene) captured variance between 60 and 90%, with validation and training R2 between 0.6 and 0.9. With this methodology, it was possible to calibrate a monitoring tool for pigments quantification, as a bulk and as individual compounds, proving that 2D fluorescence spectroscopy and climatic data combined with chemometric tools can be used to assess simultaneously and at real time different pigments in D. salina biomass production.
Marta Sá; Alzira Ramos; Joana Monte; Carla Brazinha; Claudia F. Galinha; João G Crespo. Development of a monitoring tool based on fluorescence and climatic data for pigments profile estimation in Dunaliella salina. Environmental Biology of Fishes 2019, 32, 363 -373.
AMA StyleMarta Sá, Alzira Ramos, Joana Monte, Carla Brazinha, Claudia F. Galinha, João G Crespo. Development of a monitoring tool based on fluorescence and climatic data for pigments profile estimation in Dunaliella salina. Environmental Biology of Fishes. 2019; 32 (1):363-373.
Chicago/Turabian StyleMarta Sá; Alzira Ramos; Joana Monte; Carla Brazinha; Claudia F. Galinha; João G Crespo. 2019. "Development of a monitoring tool based on fluorescence and climatic data for pigments profile estimation in Dunaliella salina." Environmental Biology of Fishes 32, no. 1: 363-373.
Dunaliella salina is well-known for its high content in carotenoids and glycerol. Nevertheless, Dunaliella salina has also a high content in lipids, including polar lipids, which are suitable for nutraceutical/cosmeceutical applications. This work proposes a sustainable process to maximise the potential of Dunaliella salina for the production of distinct fractions of carotenoids, glycerol, polar lipids and proteins, which may contribute to improve the revenues of the microalgae industry. In this work, extraction with non-hazardous solvents and organic solvent nanofiltration are integrated, in order to obtain added-value products and glycerol. Also, aiming to separate carotenoids from glycerides, a saponification process is proposed. High overall recoveries were obtained for carotenoids (85%), glycerol (86%), polar lipids (94%) and proteins (95%). In order to evaluate the profitability of the proposed biorefinery, an economic assessment was accomplished. Both CAPEX and OPEX (Capital and Operating expenditure) were calculated, likewise the Return of Investment (ROI).
Joana Monte; Cláudia Ribeiro; Celina Parreira; Luís Costa; Lena Brive; Susana Casal; Carla Brazinha; João G. Crespo. Biorefinery of Dunaliella salina: Sustainable recovery of carotenoids, polar lipids and glycerol. Bioresource Technology 2019, 297, 122509 .
AMA StyleJoana Monte, Cláudia Ribeiro, Celina Parreira, Luís Costa, Lena Brive, Susana Casal, Carla Brazinha, João G. Crespo. Biorefinery of Dunaliella salina: Sustainable recovery of carotenoids, polar lipids and glycerol. Bioresource Technology. 2019; 297 ():122509.
Chicago/Turabian StyleJoana Monte; Cláudia Ribeiro; Celina Parreira; Luís Costa; Lena Brive; Susana Casal; Carla Brazinha; João G. Crespo. 2019. "Biorefinery of Dunaliella salina: Sustainable recovery of carotenoids, polar lipids and glycerol." Bioresource Technology 297, no. : 122509.
Two-dimensional (2D) fluorescence spectroscopy was investigated as a monitoring tool for cultivation, harvesting, and effluent treatment of Dunaliella salina with high carotenoid concentration; aiming to improve the production process and minimise costs. Chemometric analysis, namely Principal Component Analysis (PCA) and Projection to Latent Structures (PLS), were used to build models for estimation of cellular concentration, cellular viability, and nitrate concentration in media. The estimations were based on fluorescence excitation-emission matrices (EEMs) acquired directly from algal suspensions. Cell concentration during cultivation and harvesting can be predicted by a single model capturing 92.0% of the variance, and with R2 of 0.92 and 0.97, for training and validation, respectively. Cell viability during harvesting by ultrafiltration was modelled with 79% of variance and R2 of 0.79 for training and 0.73 for validation. Nitrate concentration was successfully predicted during cultivation and permeate treatment using a single model with 81.8% of variance and R2 of 0.82 for training and 0.80 for validation. Therefore, this work demonstrates the strong potential of combining 2D fluorescence and chemometrics for monitoring different processes during microalgae production.
Marta Sá; Joana Monte; Carla Brazinha; Claudia F. Galinha; João G. Crespo. Fluorescence coupled with chemometrics for simultaneous monitoring of cell concentration, cell viability and medium nitrate during production of carotenoid-rich Dunaliella salina. Algal Research 2019, 44, 101720 .
AMA StyleMarta Sá, Joana Monte, Carla Brazinha, Claudia F. Galinha, João G. Crespo. Fluorescence coupled with chemometrics for simultaneous monitoring of cell concentration, cell viability and medium nitrate during production of carotenoid-rich Dunaliella salina. Algal Research. 2019; 44 ():101720.
Chicago/Turabian StyleMarta Sá; Joana Monte; Carla Brazinha; Claudia F. Galinha; João G. Crespo. 2019. "Fluorescence coupled with chemometrics for simultaneous monitoring of cell concentration, cell viability and medium nitrate during production of carotenoid-rich Dunaliella salina." Algal Research 44, no. : 101720.