| 1. |
- Morlighem, M., et al.
(författare)
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BedMachine v3 : Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation
- 2017
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 44:21, s. 11051-11061
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Tidskriftsartikel (refereegranskat)abstract
- Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.420.05m, which is 7cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.
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| 2. |
- Budnyak, Tetyana M., et al.
(författare)
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Bile acids adsorption by chitoan-fumed silica enterosorbent
- 2019
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Ingår i: Colloid and Interface Science Communications. - : Elsevier BV. - 2215-0382. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid composites from chitosan and fumed silica were synthesized and applied for the adsorption of bile acids (BA), e.g. cholic (CA) and taurocholic (TCA) acids. The chitosan immobilization was confirmed by infrared spectroscopy and the corresponding stability of the composites was confirmed by tests with the analytical reagent ninhydrin. The effects of adsorption parameters such as initial concentration of BA and pH were evaluated. The synthesized composite shows higher affinity and adsorption capacity toward TCA in comparison to CA. The results of equilibrium study for BA adsorption by the synthesized composite were analyzed by application of Langmuir, Freundlich and Temkin isotherm models. Adsorption capacity of chitosan-fumed silica composite was 97 mu mol/g for TCA and 43 mu mol/g for CA based on the applied Freundlich isoterm model. Our results show the potential of biopolymeric-inorganic composites for application as efficient enterosorbent in medical practice.
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| 3. |
- Budnyak, Tetyana, et al.
(författare)
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Nucleotide Interaction with a Chitosan Layer on a Silica Surface : Establishing the Mechanism at the Molecular Level
- 2021
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:4, s. 1511-1520
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Tidskriftsartikel (refereegranskat)abstract
- The growing interest in gene therapy is coupled with the strong need for the development of safe and efficient gene transfection vectors. A composite based on chitosan and fumed silica has been found to be a prospective gene delivery carrier. This study presents an investigation of the nature of the bonds between a series of nucleotides with a chitosan layer deposited on a fumed silica surface. Experimentally measured surface complex formation constants (logK) of the nucleotides were found to be in the range of 2.69–4.02, which is higher than that for the orthophosphate (2.39). Theoretically calculated nucleotide complexation energies for chitosan deposited on the surface range from 11.5 to 23.0 kcal·mol–1, in agreement with experimental data. The adsorption of nucleotides was interpreted using their calculated speciation in an aqueous solution. Based on the structures of all optimized complexes determined from quantum-chemical PM6 calculations, electrostatic interactions between the surface-located NH3+ groups and −PO3H––/–PO32– fragments of the nucleotides were identified to play the decisive role in the adsorption mechanism. The saccharide fragment of monophosphates also plays an important role in the binding of the nucleotides to chitosan through the creation of hydrogen bonds.
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| 4. |
- Lu, Can, et al.
(författare)
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Nanostructured core-shell metal borides-oxides as highly efficient electrocatalysts for photoelectrochemical water oxidation
- 2020
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 12:5, s. 3121-3128
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen evolution reaction (OER) catalysts are critical components of photoanodes for photoelectrochemical (PEC) water oxidation. Herein, nanostructured metal boride MB (M = Co, Fe) electrocatalysts, which have been synthesized by a Sn/SnCl2 redox assisted solid-state method, were integrated with WO3 thin films to build heterojunction photoanodes. As-obtained MB modified WO3 photoanodes exhibit enhanced charge carrier transport, amended separation of photogenerated electrons and holes, prolonged hole lifetime and increased charge carrier density. Surface modification of CoB and FeB significantly enhances the photocurrent density of WO3 photoanodes from 0.53 to 0.83 and 0.85 mA cm(-2), respectively, in transient chronoamperometry (CA) at 1.23 V vs. RHE (V-RHE) under interrupted illumination in 0.1 M Na2SO4 electrolyte (pH 7), corresponding to an increase of 1.6 relative to pristine WO3. In contrast, the pristine MB thin film electrodes do not produce noticeable photocurrent during water oxidation. The metal boride catalysts transform in situ to a core-shell structure with a metal boride core and a metal oxide (MO, M = Co, Fe) surface layer. When coupled to WO3 thin films, the CoB@CoOx nanostructures exhibit a higher catalytic enhancement than corresponding pure cobalt borate (Co-B-i) and cobalt hydroxide (Co(OH)(x)) electrocatalysts. Our results emphasize the role of the semiconductor-electrocatalyst interface for photoelectrodes and their high dependency on materials combination.
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| 5. |
- Ma, Zili, et al.
(författare)
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Combining Electrocatalysts and Biobased Adsorbents for Sustainable Denitrification
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:10, s. 3651-3660
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Tidskriftsartikel (refereegranskat)abstract
- Efficient treatment of domestic and industrial wastewater is one of the major challenges of the 21st century. Among the inorganic pollutants, nitrogen species are significant contaminants and the management of the nitrogen cycle is one the most crucial parts of wastewater purification. Herein, we report an integrated method that minimizes the amount of chemicals used, can be empowered by renewable energy, uses renewables materials for ammonia recovery, and is scalable. Complete denitrification of wastewater was achieved by combining electrochemical and adsorption treatment for real wastewater samples from the Stockholm water pilot plant. About 98% of nitrate was selectively converted to ammonia over abundant copper electrocatalysts in the presence of Na2SO4-supporting electrolyte at -0.6 V vs reversible hydrogen electrode (RHE) within 3 h. The valorized nitrate in the form of ammonia could be recovered by means of cheap kraft lignin-SiO2 sorbents to achieve total denitrification. The presented method is economically feasible, scalable, and contributes to sustainable recycling within a circular economy.
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| 6. |
- Nair, Santhosh S., et al.
(författare)
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Converting cellulose nanocrystals into photocatalysts by functionalisation with titanium dioxide nanorods and gold nanocrystals
- 2020
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:61, s. 37374-37381
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanocrystals (CNCs) are promising building blocks for water purification due to their high surface area, tuneability of surface charge and grafting of surface groups depending on the pollutants. In this report we have converted CNCs into photocatalysts, without altering the surface groups, byin situgrowth of TiO(2)nanorods (NRs) and functionalization with Au nanocrystals (NCs) for enhanced light absorption. The control of the density of the NRs assures that the CNC surface and functionalities are accessible for the pollutant, followed by the photocatalytic degradation on the light absorption layer under solar illumination. This seed-mediated NR synthesis can be applied to realize a series of CNC-inorganic NR photocatalysts. The low temperature (90 degrees C compared to commonly reported growth at 150 degrees C) of the NR growth provides the opportunity to use nanostructured biopolymers as functional substrates for preparation of photocatalysts using a bio-inspired design.
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| 7. |
- 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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