Suchergebnisse

Efficient energy storage systems are increasingly needed due to advances in portable electronics and transport vehicles, lithium-ion batteries standing out among the most suitable energy storage systems for a large variety of applications. In lithium-ion batteries, the porous separator membrane plays a relevant role as it is placed between the electrodes and serves as a charge transfer medium and affects the cycle behavior. Typically, porous separators membranes are comprised of a synthetic polymeric matrix embedded in the electrolyte solution. The present chapter focus on recent advances in synthetic polymers for porous separation membranes, as well as on the techniques for membrane preparation and physicochemical characterization. The main challenges to improve synthetic polymer performance for battery separator membrane applications are also discussed. ; Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019, UID/QUI/50006/2019, UID/QUI/0686/2016 and UID/EMS/00151/2019. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the project PTDC/FIS-MAC/28157/2017, Grants 38 SFRH/BPD/117838/2016 (JNP). and SFRH/BPD/112547/2015 (C.M.C). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA ...

Nanocomposite membranes (NCMs) of poly(vinylidene fluoride-hexafluoropropylene), PVDF-HFP, with different yttrium carbonate and magnetite loadings, are prepared, and their dual adsorption capacity over neutral arsenite and anionic arsenate species is evaluated. The nanoparticles (NPs) and the corresponding NCMs are fully characterized in morphology, microstructure, thermal, and surface properties. The nanocomposite membranes present a micrometric porous structure with a homogeneous distribution of the active nanoparticles. Chemical, thermal, and water-contact angle characteristics of the NCMs point out that they maintain the chemical and thermal stability of the polymer while improving the wettability. Arsenic removal depends on NP loading and pH of the media. For instance, efficiencies close to 100% are achieved for arsenate species under acidic conditions, while adsorption capacity over arsenite is also incremented above 80%. Fe3O4/PVDF-HFP nanocomposite shows a dual affinity for the adsorption of As(III) and As(V) species, with the maximum adsorption capacities of 92.82 and 137.08 mg g−1, respectively. In addition, both NCMs are easily activated and reused without significant efficiency loss. Consequently, the nanocomposite membranes represent low-cost, reusable, and efficient water remediation systems suitable for the long-term removal of As(III) and As(V) under conditions mimicking real polluted surface and groundwater. ; This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Projects UID/FIS/04650/20132019 and UID/QUI/50006/2019 and project PTDC/FIS-MAC/28157/2017. H. Salazar thanks the FCT for grant SFRH/BD/122373/2016. Financial support from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs is also acknowledged.

Semiconductor-based heterogeneous photocatalysis has been one of the most promising processes for the treatment of contaminated water. Among the available catalysts, titanium dioxide (TiO2) presents the best photocatalytic properties, being chemically and biologically inert, stable, non-toxic, cheap and easy to produce. However, its energy bang gap lies in the ultraviolet (UV) range, which is responsible for a reduced spectral activation, since UV radiation corresponds to only 5% of the solar spectrum [1]. For this reason, one of the main purposes of the scientific community has been to improve the photocatalytic performance of TiO2, namely through an adequate doping of this material, or through the creation of nanocomposites, to enable photocatalysis occurrence by the incidence of visible light. One alternative concerns the application of nanocomposites of TiO2 with graphene and graphene oxide to photocatalytic processes [2]. In this work, nanocomposites of TiO2 with different weight concentrations of graphene and graphene oxide (namely 0.5%, 1%, 1.5% and 3%) were synthetized by a one-step hydrothermal method and characterized in terms of morphology, crystalline structure, vibrational modes and optical band gap. The photocatalytic activity of these nanocomposites was then evaluated through the degradation of methylene blue and ciprofloxacin solutions under UV and visible radiation. The results indicated that the studied nanocomposites presented higher degradation rates of the methylene blue than the pure TiO2, which increased with the content of graphene/graphene oxide. However, these composites proved to be less suitable to degrade the ciprofloxacin solution than the pure TiO2 nanoparticles. ; Portuguese Foundation for Science and Technology (FCT) - UID/FIS/04650/2013, PTDC/CTM-ENE/5387/2014 and SFRH/BD/98616/2013; Basque Government Industry Department under the ELKARTEK Program. ...

Metronidazole (MNZ) is a recalcitrant antibiotic with toxic and carcinogenic effects in aquatic environments. In this work, Fe-5(FO4)(4)(OH)(3)center dot 2H(2)O (giniite) particles were synthesised with three different alkaline cations (Li+, Na+ and K+) and used as Fenton catalysts for MNZ removal. It is shown that the addition of different cations during the hydrothermal synthesis process promote different morphologies from asterisk-like to flower-like and branches-like, maintaining the crystalline structure of pure giniite. The photo-Fenton activity of these particles was then evaluated through the degradation of MNZ under sunlight radiation for 9 h. The results indicate that the alkaline cation has a predominant role in the photo-Fenton efficiency, as demonstrated by the superior degradation efficiencies of Na@giniite particles (91.2% and 72.5% with giniite concentration of 0.2 g L-1 and 0.07 g L-1, respectively), related with its high surface area (10.7 m(2) g(-1)). Thus, it is demonstrated the suitability of Na@giniite particles as Fenton catalyst for MNZ removal from water. (C) 2020 Elsevier Ltd. All rights reserved. ; This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020 and PEST-C/QUI/UIO686/2014 and under projects PTDC/BTM-MAT/28237/2017 and PTDC/FIS-MAC/28157/2017. We also thank the financial support from e FCT for grants SFRH/BD/122373/2016 (HS), SFRH/BPD/112547/2015 (CMC), IF/01516/2013 (SF), CTTI-70/19-CF(1) (P.M), and CEECIND/00833/2017 (RG). The authors thank funding by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, ...

A poly(vinylidene fluoride) (PVDF) and its copolymers are polymers that, in specific crystalline phases, show high dielectric and piezoelectric values, excellent mechanical behavior and good thermal and chemical stability, suitable for many applications from the biomedical area to energy devices. This chapter introduces the main properties, processability and polymorphism of PVDF. Further, the recent advances in the applications based on those materials are presented and discussed. Thus, it shown the key role of PVDF and its copolymers as smart and multifunctional material, expanding the limits of polymer-based technologies. ; FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2019, and UID/QUI/0686/2019 and project PTDC/FIS-MAC/28157/2017, PTDC/BTMMAT/28237/2017, PTDC/EMD-EMD/28159/2017. The author also thanks the FCT for financial support under grant SFRH/BPD/112547/2015 (C.M.C.), SFRH/BPD/98109/2013 (V.F.C.), SFRH/BD/140698/2018 (R.B.P.), SFRH/BPD/96227/2013 (P.M.), SFRH/BPD/121526/2016 (D.M.C.), SFRH/BPD/97739/2013 (V. C.), SFRH/BPD/90870/2012 (C.R.). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including FEDER financial support) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA ...