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Item type:Publication, Access status: with files , Functionalization of carbon electrodes with nanotitania by atomic layer deposition(Hindawi Publishing Corporation, 2022-10-12); ; ; ; Carbon fibers are materials with a very high surface area and are interesting for applications such as filters, fire-resistant heat insulation, photocatalysis, and capacitor electrodes. Moreover, thermal burnout can easily remove these fibers, making them ideal templates for high-precision coatings or keeping them within the coated structure, generating nanostructured composites. In this work, two different substrates, carbon felt and bacterial nanocellulose were coated by TiO2 with atomic layer deposition (ALD). After deposition, the templates were pyrolyzed or further removed by burnout in the air. The microstructure evolution of the 3D interlocked-fibers structures was characterized by scanning electron microscopy and nitrogen adsorption surface area after each step. Stable anatase was present as a single TiO2 phase even after heat treatment at 800°C. Moreover, electrochemical impedance spectroscopy and constant current charge-discharge were employed to investigate the electrochemical properties of the samples. Our results show that all samples display a uniform layer after ALD and that the surface area decreases with an increasing number of ALD cycles. After burnout, the 3D structures presented a straw-like appearance to the shells. Nonetheless, both samples presented a power density comparable to a porous NiO/C, with the pyrolyzed bacterial nanocellulose sample displaying a higher pseudocapacitance performance than the carbon-felt samples.Publicationtype: Journal Article60 104 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , TiO2 photocatalyst nanoparticle separation: flocculation in different matrices and use of powdered activated carbon as a precoat in low-cost fabric filtration(Hindawi Publishing Corporation, 2014-02-23); ; ; ; Separation of photocatalyst nanoparticles is a problem impeding widespread application of photocatalytic oxidation. As sedimentation of photocatalyst particles is facilitated by their flocculation, the influence of common constituents of biologically pretreated wastewaters (NaCl, NaHCO3, and their combination with humic acid sodium salt) on flocculation was tested by the pipetmethod. Results showed that the impact of these substances on TiO2 nanoparticle flocculation is rather complex and strongly affected by pH.When humic acid was present, TiO2 particles did not show efficient flocculation in the neutral and slightly basic pH range. As an alternative to photocatalyst separation by sedimentation, precoat vacuum filtration with powdered activated carbon (PAC) over low-cost spunbond polypropylene fabrics was tested in the presence of two PAC types in aqueous NaCl and NaHCO3 solutions as well as in biologically treated greywater and in secondary municipal effluent. PAC concentrations of ≥ 2g/L were required in order to achieve a retention of nearly 95% of the TiO2 nanoparticles on the fabric filter when TiO2 concentration was 1 g/L. Composition of the aqueous matrix and PAC type had a slight impact on precoat filtration. PAC precoat filtration represents a potential pretreatment for photocatalyst removal by micro- or ultrafiltration.Publicationtype: Journal ArticleScopus© Citations 13 471 556 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Modelling of ballistic impact over a ceramic-metal protection system(Hindawi Publishing Corporation, 2013-11-18); ; ; ; The behavior of ceramic-metal protection against a projectile impact is modeled. The model takes into account the mass and velocity for each stage of the phenomenon. A former model was modified considering more realistic parameters such as geometries and deformation profile. To analyze the model, simulations on different parameters have been run. The impact results of different ballistic projectiles were simulated, and the movement was plotted. In addition, a deterministic simulation on the mechanical properties of the back metal plate properties was done.Publicationtype: Journal ArticleScopus© Citations 5 342 455