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Item type:Publication, Access status: with files , Molecular fluctuations in mixed-metal MOF-74: influence of the metal composition(Royal Society of Chemistry (RSC), 2025-08-18); ; ; ; A selected series of metal–organic frameworks M-MOF-74 (M = Mg, Co, Ni) and mixed metal MM-MOF-74 (Mg/Co or Mg/Ni) with different compositions of metal atoms have been prepared and further investigated by broadband dielectric spectroscopy (BDS) in a wide temperature range. The dielectric spectra show at least two relaxation processes. Process-A is observed only for the Ni-containing MOFs and is attributed to localized fluctuations of the metal oxide corners. Relaxation processes-B and -C are observed for all prepared MOFs, except that process-B is not observed for Ni-MOF-74. Large-angle fluctuations such as free rotations of the linkers can be excluded due to the structure of MOF-74, but small-angle fluctuations such as torsions are possible. According to numerical simulations carried out for MOF-74, process-B can be attributed to inward and outward fluctuations of the linkers relative to the pore center. Process-C is related to small-angle rotational fluctuations of the linker together with co-rotations of the metal nodes. The latter interpretation is supported by the dependence of the activation energy of the relaxation rate of process-C on the metal composition of the MOFs, which is discussed in terms of the bond lengths between the metal atoms and the linker which decrease in the sequence Mg, Co and Ni.Publicationtype: Journal Article41 446 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Flash phase engineering of MoS2 nanofilms for enhanced photoelectrochemical performance(2024-02-05); 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The influence of sample mass (scaling effect) on the synthesis and structure of non-graphitizing carbon (biochar) during the analytical pyrolysis of biomass(Royal Society of Chemistry (RSC), 2023-05-02); 5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Influence of redox initiator component ratios on the emulsion copolymerisation of vinyl acetate and neodecanoic acid vinyl ester(Royal Society of Chemistry (RSC), 2022-05-11); ; Publicationtype: Journal ArticleScopus© Citations 3 61 204 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Microbubble enhanced mass transfer efficiency of CO2 capture utilizing aqueous triethanolamine for enzymatic resorcinol carboxylation(Royal Society of Chemistry (RSC), 2021-01-20); ; ; ; The present study focuses on the aeration of aqueous triethanolamine acting as reaction medium for biocatalytic carboxylations. For enhancing mass transfer in a bubble column reactor, microbubble aeration is applied and compared to conventional macrobubble aeration. Application of a 0.5 μm porous sparger enables microbubble CO2 aeration with bubble size distributions below 150 μm in Sauter mean diameter, correlating with the highest measured mass transfer rates. During CO2 saturation of the aqueous triethanolamine, bubble size distributions changed according to the level of CO2 saturation. For microbubbles, less foaming was observed compared to macrobubble aeration by a 10 μm porous sparger. This microbubble effect is attributed to their accelerated dissolution assisted by the Laplace pressure lowering the amount of bubbles reaching the surface of the liquid. The experiments reveal that the rate of interfacial area generation, which is calculated based on measured bubble size distributions, influences the biocatalyst activity.Publicationtype: Journal ArticleScopus© Citations 19 161 141 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , The degree and source of plastic recyclates contamination with polycyclic aromatic hydrocarbons(2020-12-21); ; ; In this research, the degree and source of recyclates contamination with polycyclic aromatic hydrocarbons (PAH) was studied in eight different polyolefin recyclate samples; four originating from post-consumer packaging waste and four originating from a mixed source (post-industrial, post-commercial, and post-consumer). The aim was to assess the applicability of these recyclates in the different products' categories. Furthermore, the impact of previous contamination with PAH was excluded by analysing pure plastics before and after undergoing simulated recycling processes. Polythene recyclates originating from post-consumer plastic packaging waste had lower concentrations of the 16-US-EPA PAH (922.15 ± 420.75 μg kg-1) in comparison to the ones of a mixed origin (2155.43 ± 991.85 μg kg-1), r = -0.35, p > 0.05. The degree of recyclates contamination with PAH was always within the REACH limits for consumer products (<1.0 mg kg-1). On the other hand, only polythene recyclate sample originating from post-commercial waste did not comply with the REACH limits for children articles (0.5 mg kg-1). Hence, the source of plastic waste defines the quality of recyclates. All in all, the results indicated that the contamination of polyolefin recyclates with PAH is attributed to the material's previous contamination, or the sorption of plastics to organic compounds from the surrounding environment. Exposing plastics containing PAH additives to heat during extrusion could result in further accumulation of PAH in plastics.Publicationtype: Journal ArticleScopus© Citations 17 192 161 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Synthesis and charge transfer characteristics of a ruthenium-Acetylide complex(2020-11-27); ; ; ; A novel ruthenium-Acetylide complex was synthesised and characterised in solid state and solution. Thin films of the complex were evaporated on silver and gold foils in ultra high vacuum in order to probe the electronic properties with photoemission spectroscopy. The charge transfer characteristics of the complex with the strong acceptor F6TCNNQ were investigated by UV-vis absorption in solution as well as at an interface with photoemission spectroscopy. A new excitation in the former optical gap of the pristine materials was probed in solution. Moreover, it was possible to identify the oxidised complex as well as the reduced acceptor by X-ray photoemission spectroscopy. In particular, our data reveal that oxidation of the complex mainly occurs at the Ru centre. The charge transfer can be characterised as localised and mainly ionic although signs of a reaction of the acceptors aminogroups with the ruthenium-Acetylide complex were found. This journal isPublicationtype: Journal Article19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Capacitive behavior of activated carbons obtained from coffee husk(Royal Society of Chemistry (RSC), 2020-10-15)7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Elucidating the ionic liquid distribution in monolithic SILP hydroformylation catalysts by magnetic resonance imagingMonolithic silicon carbide supported ionic liquid-phase (SILP) Rh-catalysts have very recently been introduced for gas-phase hydroformylation as an important step toward industrial upscaling. This study investigates the monolithic catalyst system in combination with different impregnation procedures with non-invasive magnetic resonance imaging (MRI). The findings were supported by X-ray microtomography (micro-CT) data of the monolithic pore structure and a catalytic performance test of the catalyst system for 1-butene gas-phase hydroformylation. MRI confirmed a homogeneous impregnation of the liquid phase throughout the full cross-section of the cylindrical monoliths. Consistent impregnations from one side to the other of the monoliths were achieved with a stabilizer in the system that helped preventing inhomogeneous rim formation. External influences relevant for industrial application, such as long-term storage and temperature exposure, did not affect the homogeneous liquid-phase distribution of the catalyst. The work elucidates important parameters to improve liquid-phase catalyst impregnation to obtain efficient monolithic catalysts for industrial exploitation in gas-phase hydroformylation as well as other important industrial processes.Publicationtype: Journal Article51 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Polyurea-crosslinked biopolymer aerogel beads(Royal Society of Chemistry (RSC), 2020); ; ; ; Polyurea-crosslinked calcium alginate (X-Ca-alginate) and chitosan (X-chitosan) aerogel beads have been prepared via reaction of an aliphatic triisocyanate (Desmodur N3300) with the –OH groups of calcium alginate or the –NH2 groups of chitosan preformed wet gels, forming surface urethane or urea groups, respectively, and the subsequent formation of a polyurea conformal coating of the network via reaction of the triisocyanate with adsorbed water retained on the inner surfaces of the wet gels. That conformal coating is evident by SEM, which showed that all aerogels, native and crosslinked, were fibrous and their micromorphology did not change after crosslinking. The chemical identity of the new materials was confirmed with ATR-FTIR spectroscopy and solid-state 13C and 15N CPMAS NMR spectroscopy. The percent uptake of polyurea in X-Ca-alginate aerogels (43–66%) and X-chitosan aerogels (31–51%) was calculated from skeletal density data. This work expands the methodology for polymer-crosslinked alginate aerogels from monoliths to beads, and from alginates to chitosan, establishing its generality for all biopolymer aerogels. Possible applications of these materials include environmental remediation and conversion to carbon aerogels.Publicationtype: Journal ArticleScopus© Citations 26 177 206