Open Access
Zn-Ti-Al layered double hydroxides synthesized from aluminum saline slag wastes as efficient drug adsorbents
(Elsevier, 2020) Santamaría Arana, Leticia; López Aizpún, María; García Padial, Marcos; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Gobierno de Navarra / Nafarroako Gobernua, PI017-PI039 CORRAL; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This work reports the synthesis of Zinc-Titanium-Aluminum (ZnTiAl) layered double hydroxides (LDH) with various proportions of Al[sbnd]Ti and a Zn/(Al[sbnd]Ti) molar ratio of 3:1 by the co-precipitation method. Two series, made with commercial aluminum (Al) and aluminum extracted from saline slags (Al*), have been considered. Structural characterization and comparison of the two series has been made using powder X-ray diffraction (PXRD), Nitrogen physisorption at 77 K, Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Thermogravimetry measurements. The adsorption capacity of diclofenac and salicylic acid, as examples of emergent pollutants, by the different LDH on batch and fixed-bed column experiments has been analyzed. The effect of various parameters, such as the pH, the initial concentration of pollutant, the mass of adsorbent and the contact time, on the sorption behavior were studied and compared. The contact time to attain equilibrium for maximum adsorption was found to be between 100 and 400 min. The kinetic and equilibrium results were correlated to several adsorption and isotherm equation models. The synthesized materials were more effective in removing diclofenac than salicylic acid, being Zn6Al*2 the hydrotalcite that showed the highest adsorption capacity. The results showed a new application of a material obtained from the valorization of an industrial waste such as aluminum saline slags.
Open Access
Saline slag waste as an aluminum source for the synthesis of Zn–Al–Fe–Ti layered double-hydroxides as catalysts for the photodegradation of emerging contaminants
(Elsevier, 2020) Santamaría Arana, Leticia; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua, PI017-PI039 CORRAL
In this work, aluminum extracted from saline slag waste is valorized to create a layered double-hydroxide series containing zinc and various proportions of aluminum/titanium. Materials were synthesized by the co-precipitation method with an Me2+/Me3+ molar ratio of 3:1 and tested for the removal of diclofenac and salicylic acid from water under UV radiation. The incorporation of 5 wt% iron by wet impregnation is evaluated. In addition, another series of zinc, aluminum/iron materials with and without 5 wt% impregnated titanium are tested as catalysts for comparison. Structural characterization and comparison of the two series was performed by powder X-ray diffraction (PXRD), nitrogen adsorption at 77 K, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. The uncalcinated samples had a typical hydrotalcite structure with a high crystallinity; the presence of ZnO, ZnFe2O4 or Fe3O4 was found after calcination. The specific surface areas of the dried samples ranged from 78 to 199 m2/g, being highest for Zn6Al0.5Ti1.5. Overall, the results showed that the ZnAlTi series were more effective catalysts than ZnAlFe for photodegradation of the emerging contaminants diclofenac and salicylic acid, under UV light at 298 K, considering two concentrations of the organic molecules (5 and 50 μmol/dm3).
Open Access
Multifunctional nanocomposites based on kaolinite/titania/iron applied to hydrogen peroxide production and bisphenol-A removal
(Elsevier, 2024-11-06) Do Prado, Marcus Vinicius; Lima, Vinicius; Oliveira, Larissa; Nassar, Eduardo José; Marçal, Liziane; Faria, Emerson H. de; Vicente, Miguel Ángel; Trujillano, Raquel; Santamaría Arana, Leticia; Gil Bravo, Antonio; Korili, Sophia A.; Ciuffi, Katia J.; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The rising global demand for hydrogen peroxide, recognized for its eco-friendly properties, underscores the need for greener synthesis methods. Traditional production processes pose environmental risks, while direct synthesis faces challenges like water formation, explosion hazards, and stability issues, limiting industrial application. On the other hand, Bisphenol A (BPA), an endocrine disruptor widely used in plastics, presents significant environmental and health concerns due to its potential leaching into food and water. The present work introduces efficient and selective photocatalysts aimed at sustainable hydrogen peroxide synthesis and BPA degradation. Both processes were enhanced by the synergistic properties of Fe2O3–TiO2 nanoparticles dispersed within a kaolinite matrix. The Fe2O3-TiO2 photocatalysts, characterized by photoluminescence spectroscopy and X-ray diffraction, showed reduced emission upon iron incorporation and anatase presence on the kaolinite surface. The photocatalytic activity was evaluated through hydroxylation of terephthalic acid, revealing a 127 umol/L min hydroxylation rate for the KaFeTi400 sample. BPA degradation studies indicated optimal performance in acidic conditions, achieving 96 % removal in 2 h and 98 % in 4 h, with the addition of H2O2 enhancing efficiency. Further, the photocatalyst facilitated benzyl alcohol oxidation to benzaldehyde, demonstrating a H2O2 production rate of 120 umol. These findings highlight the multifunctional capabilities and environmental benefits of the photocatalyst, underscoring its potential for sustainable hydrogen peroxide synthesis and broader applications in environmental remediation. The catalysts address the pressing challenges associated with hydrogen peroxide synthesis and pollutant removal, particularly in the context of sustainability and environmental impact.
Open Access
Multifunctional heterogeneous catalysts: Tetrakis (pentafluorophenyl)porphinato]iron(III) immobilized on amine-functionalized Diatomaceous Earth for catalytic and adsorption applications
(Elsevier, 2023) Do Prado, Marcus Vinicius; González, Beatriz; Vicente, Miguel Ángel; Trujillano, Raquel; Nassar, Eduardo José; Gil Bravo, Antonio; Santamaría Arana, Leticia; Korili, Sophia A.; Marçal, Liziane; Faria, Emerson H. de; Ciuffi, Katia J.; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The use of Diatomaceous Earth (DE) as a promising support of a synthetic metalloporphyrin is reported, trying to heterogenize metalloporphyrin catalysts to mimicking enzyme site isolation and improving reaction selectivity. New multifunctional hybrid materials consisting of DE amino–functionalized with aminopropyltriethoxysilane (DE–APTES), followed by grafting with [meso–tetrakis(pentafluorophenyl)porphinato]iron(III) (DE–APTES–FeTFPP), were prepared and fully characterized. FeTFPP was grafted into DE–APTES via the amine groups (band at 1570 cm–1 ). The brown color of the materials indicated that FeTFPP was immobilized in the matrix; a Soret band characteristic of ironporphyrin located in a confined space, was found at 416 nm. Leaching studies confirmed that the ironporphyrin was entrapped and not just adsorbed on the silica surface. DE was composed of typical quartz and cristobalite crystalline phases and amorphous silica. The intensity of its characteristic reflection at 22◦ (2θ) decreased in the presence of FeTFPP, evidencing that the ironporphyrin influenced the organization of the material. Catalytic tests using DE–APTES–FeTFPP in cyclooctene epoxidation to cyclooctene oxide (56 % yield, with complete selectivity for the epoxide) and cyclohexane oxidation (4 % yield of oxidized products, with ketone/alcohol selectivity ~ 3:1), evidenced the versatility of the catalyst and the multifunctionality of the resulting hybrid materials and the ability of DE as a promising natural support for ironporphyrin catalysts. Finally, the capacity of the materials as CO2 adsorbents was evaluated in the temperature range 100–200 ◦C. DE–APTES showed a maximum adsorption capacity of 1.26 mmol/g at 100 ◦C, 18 times higher than the value found under the same conditions for the non–functionalized support.
Open Access
M(II)-Al-Fe layered double hydroxides synthesized from aluminum saline slag wastes and catalytic performance on cyclooctene oxidation
(Elsevier, 2022) Santamaría Arana, Leticia; Oliveira-Garcia, L.; Faria, Emerson H. de; Ciuffi, Katia J.; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Aluminum was extracted from saline slags via an alkaline method and employed in the synthesis of Layered Double Hydroxides (LDH) with various M2+ cations (Co, Mg, Ni and Zn), while Al and Fe were the M3+ cations, using the co-precipitation method and a M2+/M3+ 2:1 ratio. The structural characterization of the samples was performed with powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), nitrogen physisorption at 77 K, thermogravimetric analysis (TGA), temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). Their catalytic performance was tested for the oxidation of olefins (cyclooctene) and their biomimetic potential was analyzed. Results show a great selectivity towards epoxides with no other products obtained. Reaction yields followed the descending order Co4AlFe, Zn4AlFe, Ni4AlFe, and Mg4AlFe, the sample with cobalt as M2+ converting up to 85% of cyclooctene.
Embargo
Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light
(Taylor & Francis, 2018) Santamaría Arana, Leticia; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol–gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.