| 1. |
- Onwumere, Joy, et al.
(författare)
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CelluPhot : Hybrid Cellulose-Bismuth Oxybromide Membrane for Pollutant Removal
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : NLM (Medline). - 1944-8244 .- 1944-8252. ; 12:38, s. 42891-42901
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous removal of organic and inorganic pollutants from wastewater is a complex challenge and requires usually several sequential processes. Here, we demonstrate the fabrication of a hybrid material that can fulfill both tasks: (i) the adsorption of metal ions due to the negative surface charge, and (ii) photocatalytic decomposition of organic compounds. The bioinorganic hybrid membrane consists of cellulose fibers to ensure mechanical stability and of Bi4O5Br2/BiOBr nanosheets. The composite is synthesized at low temperature of 115 °C directly on the cellulose membrane (CM) in order to maintain the carboxylic and hydroxyl groups on the surface that are responsible for the adsorption of metal ions. The composite can adsorb both Co(II) and Ni(II) ions and the kinetic study confirmed a good agreement of experimental data with the pseudo-second-order equation kinetic model. CM/Bi4O5Br2/BiOBr showed higher affinity to Co(II) ions than to Ni(II) ions from diluted aqueous solutions. The bioinorganic composite demonstrates a synergistic effect in the photocatalytic degradation of rhodamine B (RhB) by exceeding the removal efficiency of single components. The fabrication of the biologic-inorganic interface was confirmed by various analytical techniques including scanning electron microscopy (SEM), scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM EDX) mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The presented approach for controlled formation of the bioinorganic interface between natural material (cellulose) and nanoscopic inorganic materials of tailored morphology (Bi-O-Br system) enables the significant enhancement of materials functionality.
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| 2. |
- A. da Cruz, Márcia G., et al.
(författare)
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Electrochemical Depolymerization of Lignin in a Biomass-based Solvent
- 2022
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 15:15
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Tidskriftsartikel (refereegranskat)abstract
- Breaking down lignin into smaller units is the key to generate high value-added products. Nevertheless, dissolving this complex plant polyphenol in an environment-friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin-derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti-corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass-based solvent, a straightforward approach to produce high value-added compounds or tailored biobased materials was demonstrated.
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| 3. |
- Budnyak, Tetyana M., et al.
(författare)
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Membrane-Filtered Kraft Lignin-Silica Hybrids as Bio-Based Sorbents for Cobalt(II) Ion Recycling
- 2020
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 5:19, s. 10847-10856
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Tidskriftsartikel (refereegranskat)abstract
- Efficient and sustainable recycling of cobalt(II) is of increasing importance to support technological development in energy storage and electric vehicle industries. A composite material based on membrane-filtered lignin deposited on nanoporous silica microparticles was found to be an effective and sustainable sorbent for cobalt(II) removal. This bio-based sorbent exhibited a high sorption capacity, fast kinetics toward cobalt(II) adsorption, and good reusability. The adsorption capacity was 18 mg Co(II) per gram of dry adsorbent at room temperature (22 degrees C) at near-neutral pH, three times higher than that of the summarized capacity of lignin or silica starting materials. The kinetics study showed that 90 min is sufficient for effective cobalt(II) extraction by the composite sorbent. The pseudo-second-order kinetics and Freundlich isotherm models fitted well with experimentally obtained data and confirmed heterogeneity of adsorption sites. The promising potential of the lignin-silica composites for industrial applications in the cobalt recovering process was confirmed by high values of desorption in mildly acidic solutions.
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| 4. |
- Budnyak, Tetyana M., et al.
(författare)
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Tailored Hydrophobic/Hydrophilic Lignin Coatings on Mesoporous Silica for Sustainable Cobalt(II) Recycling
- 2020
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 8:43, s. 16262-16273
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Tidskriftsartikel (refereegranskat)abstract
- Lignin is a renewable biopolymer, and its chemical functionalization renders it a prospective material for a plethora of applications. Within this respect, we present a method for lignin immobilization on the surface of mesoporous silica. Two types of lignins were used to prove the feasibility of the fabrication of either hydrophilic or hydrophobic biocoatings on silica. The procedure permits to immobilize 17 mg of lignosulfonate (LS) or 37 mg of kraft lignin (KL) per gram of silica. The bioinorganic composites display a synergistic effect in the adsorption of cobalt(II) ions from aqueous solutions because the adsorption efficiency outperforms the individual constituents. These results demonstrate that thin lignin overlayers, exhibiting polymer concentrations of 0.07 mg.m(-2) for LS-SiO2, and 0.14 mg.m(-2) for KL-SiO2, provide new functionality in comparison to bulk lignin and metal oxides. According to the Langmuir isotherm model, the adsorption capacity toward aqua complexes of Co(II) was found to be 75 and 59 mg.g(-1) for the LS- or KL-coated silica, respectively. The kinetic study revealed that lignin-SiO2 composites gained the features of inorganic sorbents because 1-1.5 h was sufficient for effective cobalt extraction. The adsorption on the bioinorganic composites proceeds with the pseudo-second-order kinetics model. The adsorption of Co(II) ions was confirmed by means of solid-state H-1 magic-angle spinning (MAS) NMR spectroscopy. The simplicity of the synthesis, low-cost and abundancy of substrates, high capacity, and fast kinetics make such lignin-coated silica a promising material for cobalt recovery.
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| 5. |
- de Bruin-Dickason, Caspar, et al.
(författare)
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Valorisation of used lithium-ion batteries into nanostructured catalysts for green hydrogen from boranes
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 1:7, s. 2279-2285
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Tidskriftsartikel (refereegranskat)abstract
- Cobalt-based Li-ion batteries are produced globally on a massive scale, but most are discarded to landfill at the end of their useful lifetime. In this work, an efficient cobalt catalyst for the hydrolysis of sodium borohydride to dihydrogen was prepared from lithium ion battery waste, providing a second life for valuable minerals. This material is composed of a mixed metal cobalt-aluminium oxide supported on graphene, as elucidated by a combined FTIR, Raman, SEM, scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) and energy-dispersive X-ray spectroscopy (EDS) study. The obtained metal oxide material, which exhibits an average oxidation state for Co of 2.45, is a languid catalyst at room temperature, but rapid hydrogen production of up to 49 L(H-2) min(-1) g(-1)(Co) was observed in catalytic runs heated to 70 degrees C. This carbon-supported cobalt catalyst is competitive with designed cobalt nanostructured catalysts prepared from pure precursors. This work is illustrative of the opportunities which arise when e-waste is utilised as a mineral resource within the scope of a circular economy.
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| 6. |
- Jaworski, Aleksander, et al.
(författare)
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14N, 13C, and 119Sn solid-state NMR characterization of tin(II) carbodiimide Sn(NCN)
- 2021
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Ingår i: Zeitschrift für Naturforschung. B, A journal of chemical sciences. - : Walter de Gruyter GmbH. - 0932-0776 .- 1865-7117. ; 76:10-12, s. 745-750
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Tidskriftsartikel (refereegranskat)abstract
- We report the first magic-angle spinning (MAS) nuclear magnetic resonance (NMR) study on Sn(NCN). In this compound the spatially elongated (NCN)(2)- ion is assumed to develop two distinct forms: either cyanamide (NEC-N2-) or carbodiimide (N-=C=N-). Our N-14 MAS NMR results reveal that in Sn(NCN) the (NCN)(2-) groups exist exclusively in the form of symmetric carbodiimide ions with two equivalent nitrogen sites, which is in agreement with the X-ray diffraction data. The N-14 quadrupolar coupling constant vertical bar C-Q vertical bar approximate to 1.1 MHz for the N-=C=N- ion in Sn(NCN) is low when compared to those observed in molecular compounds that comprise cyano-type N C- moieties (vertical bar C-Q vertical bar > 3.5 MHz). This together with the information from N-14 and C-13 chemical shifts indicates that solid-state NMR is a powerful tool for providing atomic-level insights into anion species present in these compounds. The experimental NMR results are corroborated by high-level calculations with quantum chemistry methods.
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| 7. |
- Ma, Zili, et al.
(författare)
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Semi-transparent quaternary oxynitride photoanodes on GaN underlayers
- 2020
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 56:86, s. 13193-13196
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Tidskriftsartikel (refereegranskat)abstract
- Conformal atomic layer deposition (ALD) technique is employed to make semi-transparent TaOxNy, providing the possibility to build semi-transparent oxy(nitride) heterojunction photoanodes on conductive substrates. A generalized approach was developed to manufacture semi-transparent quaternary metal oxynitrides on conductive substrates beyond semi-transparent binary Ta3N5 photoanodes aiming for wireless tandem photoelectrochemical (PEC) cells.
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| 8. |
- Piątek, Jędrzej, et al.
(författare)
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Glycine-functionalized silica as sorbent for cobalt(II) and nickel(II) recovery
- 2020
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 530
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Tidskriftsartikel (refereegranskat)abstract
- We disclose that glycine functionalized silica particles (SiO2-Gly) are highly effective sorbents for the removal of Co(II) and Ni(II) ions from aqueous solution. SiO2-Gly can be prepared from commercial silica gel in a high yielding two step synthesis, and features a glycine concentration of 0.63 mmol.g(-1) (27 mmol.cm(-2)). This material can recover up to 2.81 mmol.g(-1) of Co(II) ions or 3.02 mmol.g(-1) of Ni(II) ions from aqueous solution, a capacity which is tenfold higher than unmodified silica and comparable to the best performing sorbents reported in the literature. These sorption capacities are superstoichiometric in relation to the concentration of glycine on the surface. Sorption of cobalt(II) was improved by addition of ammonia to leaching solutions to give rise to more readily absorbed cobalt amine complexes. Regeneration of sorbent was investigated by desorption of adsorbed metals under mildly acidic solutions, and efficient desorption was noted for both metals. To probe the mechanism of sorption, a thorough characterization campaign involving TGA, FTIR, nitrogen adsorption/desorption, SEM, solid state NMR, solid state UV-Vis-NIR, -COOH titration and pH(pzc) - pH drift methods was undertaken. Our mechanistic study indicated that adsorption was mediated by electrostatic interaction.
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| 9. |
- Piątek, Jędrzej, 1993-, et al.
(författare)
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Organic-inorganic interface chemistry for sustainable materials
- 2023
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Ingår i: Zeitschrift für Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2196-7105 .- 2194-4946. ; 238:3-4, s. 73-85
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Forskningsöversikt (refereegranskat)abstract
- This mini-review focuses on up-to-date advances of hybrid materials consisting of organic and inorganic components and their applications in different chemical processes. The purpose of forming such hybrids is mainly to functionalize and stabilize inorganic supports by attaching an organic linker to enhance their performance towards a target application. The interface chemistry is present with the emphasis on the sustainability of their components, chemical changes in substrates during synthesis, improvements of their physical and chemical properties, and, finally, their implementation. The latter is the main sectioning feature of this review, while we present the most prosperous applications ranging from catalysis, through water purification and energy storage. Emphasis was given to materials that can be classified as green to the best in our consideration. As the summary, the current situation on developing hybrid materials as well as directions towards sustainable future using organic-inorganic hybrids are presented.
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| 10. |
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