Person:
Pellejero, Ismael

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/49751

Last Name

Pellejero

First Name

Ismael

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Ciencias

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InaMat2. Instituto de Investigación en Materiales Avanzados y Matemáticas

ORCID

0000-0002-8448-7543

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811285

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Now showing 1 - 10 of 13

Open Access
In situ synthesis of SERS-active Au@POM nanostructures in a microfluidic device for real-time detection of water pollutants
(ACS, 2020) Lafuente, Marta; Pellejero, Ismael; Clemente, Alberto; Urbiztondo, Miguel A.; Mallada, Reyes; Reinoso, Santiago; Pina, María del Pilar; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We present a simple, versatile and low-cost approach for the preparation of SERS-active regions within a microfluidic channel 50 cm in length. The approach involves the UV-light-driven formation of polyoxometalate-decorated gold nanostructures, Au@POM (POM: H3PW12O40 (PW) and H3PMo12O40 (PMo)), that self-assemble in situ on the surface of the PDMS microchannels without any extra functionalization procedure. The fabricated LoCs were characterized by SEM, UV-Vis, Raman, XRD and XPS techniques. The SERS activity of the resulting Au@POM–coated lab-on-a-chip (LoC) devices was evaluated in both static and flow conditions using Rhodamine R6G. The SERS response of Au@PW–based LoCs was found superior to Au@PMo counterparts and outstanding when compared to reported data on metal@POM nanocomposites. We demonstrate the potentialities of both Au@POM–coated LoCs as analytical platforms for real time detection of the organophosphorous pesticide Paraoxon-methyl at 10-6 M concentration level.
Open Access
Understanding blood oxygenation in a microfluidic meander double side membrane contactor
(Elsevier, 2019) Malankowska, Magdalena; Julián, Ignacio; Pellejero, Ismael; Rho, Hoon Suk; Schlautmann, Stefan; Tiggelaar, Roald M.; Pina, María del Pilar; Gardeniers, Han; Mallada, Reyes; Institute for Advanced Materials and Mathematics - INAMAT2
Lung disease is one of the most important causes of high morbidity in preterm infants. In this work, we study a simple and easy to fabricate microfluidic device that demonstrates a great potential for blood oxygenation. A meander type architecture with double side vertical membrane arrangement has been selected as reference model to investigate the oxygenation process. The design criteria for the fabricated devices has been to maximize the oxygen saturation level while ensuring the physiological blood flow in order to avoid thrombus formation and channel blockage during operation. A mathematical model for the oxygen transfer has been developed and validated by the experimental study. The obtained results demonstrate that blood was successfully oxygenated up to approximately 98% of O-2 saturation and that the oxygen transfer rate at 1 mL/min blood flow rate was approximately 92 mL/minm(2). Finally, a sensitivity analysis of the key parameters, i.e. size of the channel, oxygen concentration in the gas phase and oxygen permeation properties of the membrane, is carried out to discuss the performance limits and to settle the guidelines for future developments.
Open Access
High power illumination system for uniform, isotropic and real time controlled irradiance in photoactivated processes research
(Elsevier, 2024) Sáenz Gamasa, Carlos; Hernández Salueña, Begoña; Sanz Carrillo, Diego; Pellejero, Ismael; Gandía Pascual, Luis; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
In the study of photocatalytic and photoactivated processes and devices a tight control on the illumination conditions is mandatory. The practical challenges in the determination of the necessary photonic quantities pose serious difficulties in the characterization of catalytic performance and reactor designs and configurations, compromising an effective comparison between different experiments. To overcome these limitations, we have designed and constructed a new illumination system based in the concept of the integrating sphere (IS). The system provides uniform and isotropic illumination on the sample, either in batch or continuous flow modes, being these characteristics independent of the sample geometry. It allows direct, non-contact and real time determination of the photonic quantities as well as versatile control on the irradiance values and its spectral characteristics. It can be also scaled up to admit samples of different sizes without affecting its operational behaviour. The performance of the IS system has been determined in comparison with a second illumination system, mounted on an optical bench, that provides quasi-parallel beam (QPB) nearly uniform illumination in tightly controlled conditions. System performance is studied using three sample geometries: a standard quartz cuvette, a thin straight tube and a microreactor by means of potassium ferrioxalate actinometry. Results indicate that the illumination geometry and the angular distribution of the incoming light greatly affect the absorption at the sample. The sample light absorption efficiency can be obtained with statistical uncertainties of about 3% and in very good agreement with theoretical estimations.
Open Access
Functionalization of 3D printed ABS filters with MOF for toxic gas removal
(Elsevier, 2020) Pellejero, Ismael; Almazán, Fernando; Lafuente, María; Urbiztondo, Miguel A.; Dobrek, Martin; Bechelany, Mikhael; Julbe, Anne; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua, PC052-23; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Acrylonitrile butadiene styrene (ABS) is one of the most extensively used polymer in 3D printing manufacturing due to its competitive thermal and mechanical properties. Recently, a special attention has been devoted to novel ABS composites featuring extra functionalities e.g. in the area of VOC removal. Herein, we report on a facile protocol for the functionalization of 3D printed ABS filters with a MOF (Metal- Organic Framework) material (ZIF-8) targeting the conception of attractive gas filters. The proposed synthesis strategy consists in low temperature ALD (Atomic Layer Deposition) of ZnO on the ABS grid followed by the hydrothermal conversion of ZnO to ZIF-8, both steps being conducted at 60 °C. In such way, the method enables an effective growth of ZIF-8 without altering the stability of the polymeric ABS support. The as-fabricated ABS/ZIF-8 filters offer a promising adsorption behaviour for dimethyl methylphosphonate (~20.4 mg of DMMP per gram of ZIF-8), thus proving their potential for toxic gas capture applications.
Open Access
Assessing thermal and nonthermal contributions during CO2 hydrogenation over ruthenium catalysts: effects of the illumination conditions and the nature of the support
(Elsevier, 2024-12-05) Imizcoz Aramburu, Mikel; Pellejero, Ismael; Gandía Pascual, Luis; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua
Photothermal catalysis offers a promising approach for the clean production of carbon-neutral chemicals from CO2 through reactions with hydrogen as a renewable energy carrier. While the combined action of photons and heat from solar radiation can drive catalytic reactions, the interactions involved are very complex, depend on the catalyst composition, and often remain uncertain. Herein, we assessed the thermal and nonthermal contributions to the overall activities of a series of Ru catalysts during the photothermal hydrogenation of CO2. TiO2 (anatase/rutile mixture), anatase, ZrO2, CeO2, and SiO2 were used as supports for Ru nanoparticles (2 wt%) that were deposited using an amino-acid-assisted method. Ru@TiO2 and Ru@ZrO2 presented the best catalytic performance at relatively low reaction temperatures (220-250 °C), whereas Ru@CeO2 was the most active catalyst above 300 °C. The catalysts were tested under direct and indirect illumination conditions to assess their thermal and nonthermal contributions to the overall production of methane, with a nonthermal contribution of 60-75 % observed at the highest applied irradiance (2.2 W·cm-²). Ru@ZrO2 registered the highest nonthermal CH4 production, which is tentatively ascribable to the participation of photo-generated electrons in the catalytic reaction and the light-induced formation of oxygen vacancies. The selected catalysts were also tested under concentrated-sunlight conditions in outdoor experiments, with a maximum methane production of 200 mmolCH4·gcat-¹·h-¹ achieved over Ru@ZrO2, which resulted in 31 % CO2 conversion and 92 % selectivity for methane in a continuous flow reactor at a space velocity of 1500 mLSTP·g-¹·min-¹.
Open Access
Highly sensitive SERS quantification of organophosphorous chemical warfare agents: a major step towards the real time sensing in the gas phase
(Elsevier, 2018) Lafuente, Marta; Pellejero, Ismael; Sebastián, Víctor; Urbiztondo, Miguel A.; Mallada, Reyes; Institute for Advanced Materials and Mathematics - INAMAT2
A surface-enhanced Raman scattering (SERS)-based sensor was developed for the label-free real-time gas phase detection of dimethyl methylphosphonate (DMMP); a surrogate molecule of the G-series nerve agents which are of particular concern due to its extreme toxicity, persistence and previous deployment. The SERS platform was designed using simple elements (Au nano-particles) coated with a citrate layer, and a self-assembly procedure that yields near- optimum distances among the nanoparticles. The citrate coating acts as an effective trap of the target molecules on the immediate vicinity of the Au nanoparticle surface under ambient conditions by reversible hydrogen bonding type interactions. For the first time, we have been able to detect sub-ppm concentrations of DMMP in gas phase (130 parts-per-billion), as might be found on potential emergency scenarios. The high sensitivity, simple preparation and reusability of the SERS platforms developed in this work open up the way for immediate detection of chemical warfare agents in realistic scenarios.
Open Access
On the improvement of alveolar-like microfluidic devices for efficient blood oxygenation
(Wiley, 2021) Malankowska, Magdalena; Pellejero, Ismael; Julián, Ignacio; Rho, Hoon Suk; Pinczowski, Pedro; Tiggelaar, Roald M.; Gardeniers, Han; Mallada, Reyes; Pina, María del Pilar; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, we study alveolar-like microfluidic devices with a horizontal membrane arrangement that demonstrate a great potential as small-scale blood oxygenator. The design criteria for the fabricated devices were to maximize the oxygen saturation level and minimize liquid chamber volume while ensuring the physiological blood flow in order to avoid thrombus formation and channel blockage during operation. The liquid chamber architecture was iteratively modified upon analysis of the fluid dynamics by computer modelling. Accordingly, two alveolar type architectures were fabricated, Alveolar Design 1 (AD1) and Alveolar Design 2 (AD2), and evaluated for oxygenation of sheep blood. The attained O2 transfer rate at 1 mL/min of blood flow rate for both devices was rather similar: 123 mL·min-1 ·m-2 and 127 mL·min-1 ·m-2 for AD1 and AD2 microfluidic devices, respectively. Among the studied, AD2 type geometry would lead to the lowest pressure drop and shear stress value upon implementation in a scaled microfluidic artificial lung (µAL) to satisfy oxygenation requirements of a 2.0 kg neonate.
Open Access
The 3D-printing fabrication of multichannel silicone microreactors for catalytic applications
(MDPI, 2023) Ibáñez de Garayo Quilchano, Alejandro; Imizcoz Aramburu, Mikel; Maisterra Udi, Maitane; Almazán, Fernando; Sanz Carrillo, Diego; Bimbela Serrano, Fernando; Cornejo Ibergallartu, Alfonso; Pellejero, Ismael; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Microstructured reactors (MSRs) are especially indicated for highly demanding heterogeneous catalysis due to the small channel dimensions that minimize diffusional limitations and enhance mass and heat transport between the fluid and the catalyst. Herein, we present the fabrication protocol of the fused filament 3D printing of silicone monolithic microreactors based on a multichannel design. Microchannels of 200 to 800 µm in width and up to 20 mm in length were developed following the scaffold-removal procedure using acrylonitrile butadiene styrene (ABS) as the material for the 3D-printed scaffold fabrication, polydimethylsiloxane (PDMS) as the building material, and acetone as the ABS removing agent. The main printing parameters such as temperature and printing velocity were optimized in order to minimize the bridging effect and filament collapsing and intercrossing. Heterogeneous catalysts were incorporated into the microchannel walls during fabrication, thus avoiding further post-processing steps. The nanoparticulated catalyst was deposited on ABS scaffolds through dip coating and transferred to the microchannel walls during the PDMS pouring step and subsequent scaffold removal. Two different designs of the silicone monolithic microreactors were tested for four catalytic applications, namely liquid-phase 2-nitrophenol photohydrogenation and methylene blue photodegradation in aqueous media, lignin depolymerization in ethanol, and gas-phase CO2 hydrogenation, in order to investigate the microreactor performance under different reaction conditions (temperature and solvent) and establish the possible range of applications.
Open Access
Wettability control on microstructured polypropylene surfaces by means of O2 plasma
(Wiley, 2017) Lafuente, Marta; Martínez, Elena; Pellejero, Ismael; Artal, María del Carmen; Pina, María del Pilar; Institute for Advanced Materials and Mathematics - INAMAT2
Durable and wear resistant polypropylene surfaces with static contact angle (SCA) above 140° have been fabricated using standard photolithographic process and O2 plasma etching followed by thermal annealing at 100 °C. This microfabrication process leads to a hierarchical topography derived from the patterned microstructures and the sub‐micron roughness caused by plasma. Hydrophobicity (SCA up to 145°) remained over 14 months after fabrication. This wetting behavior is attributed to the combination of the periodic array of micro‐sized pillars with low aspect‐ratio and the submicron roughness caused by O2 plasma.
Open Access
Innovative catalyst integration on transparent silicone microreactors for photocatalytic applications
(Elsevier, 2022) Pellejero, Ismael; Clemente, Alberto; Reinoso, Santiago; Cornejo Ibergallartu, Alfonso; Navajas León, Alberto; Vesperinas Oroz, José Javier; Urbiztondo, Miguel A.; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Reproducible and controllable incorporation and immobilization of catalysts and other active particles onto silicone microreactor channels is still challenging. In this work, we present an innovative fabrication protocol to attain affordable, custom-designed photocatalytic microreactors in a fast and simple manner. In this protocol, a 3D-printed ABS microreactor mold is first dip-coated with the photocatalyst, and subsequently, the catalytic layer is transferred onto the microchannel walls by indirect immobilization during the silicone casting and scaffold removal step. Serpentine-shaped microreactors have been satisfactorily fabricated with Au@POM-impregnated TiO2 nanoparticles (Au@POM/TiO2; Au 0.18 % w/w, POM: H3PW12O40) as the integrated photocatalytic layer. The suitability of our fabrication method has been validated on the basis of the excellent photocatalytic performance shown by the microreactors in a model test reaction such as the continuous-flow photoreduction of 4-nitrophenol to 4-aminophenol with NaBH4 and monitored by UV-Vis spectroscopy.