Change search
Link to record
Permanent link

Direct link
Publications (10 of 144) Show all publications
Iqbal, M. N., Jaworski, A., Pinon, A. C., Bengtsson, T. & Hedin, N. (2023). Activity and Stability of Nanoconfined Alpha-Amylase in Mesoporous Silica. ACS Materials Science Au, 3(6), 659-668
Open this publication in new window or tab >>Activity and Stability of Nanoconfined Alpha-Amylase in Mesoporous Silica
Show others...
2023 (English)In: ACS Materials Science Au, E-ISSN 2694-2461, Vol. 3, no 6, p. 659-668Article in journal (Refereed) Published
Abstract [en]

Mesoporous silica particles (MSPs) have been studied for their potential therapeutic uses in controlling obesity and diabetes. Previous studies have shown that the level of digestion of starch by α-amylase is considerably reduced in the presence of MSPs, and it has been shown to be caused by the adsorption of α-amylase by MSPs. In this study, we tested a hypothesis of enzymatic deactivation and measured the activity of α-amylase together with MSPs (SBA-15) using comparably small CNP-G3 (2-chloro-4-nitrophenyl alpha-d-maltotrioside) as a substrate. We showed that pore-incorporated α-amylase was active and displayed higher activity and stability compared to amylase in solution (the control). We attribute this to physical effects: the coadsorption of CNP-G3 on the MSPs and the relatively snug fit of the amylase in the pores. Biosorption in this article refers to the process of removal or adsorption of α-amylase from its solution phase into the same solution dispersed in, or adsorbed on, the MSPs. Large quantities of α-amylase were biosorbed (about 21% w/w) on the MSPs, and high values of the maximum reaction rate (Vmax) and the Michaelis–Menten constant (KM) were observed for the enzyme kinetics. These findings show that the reduced enzymatic activity for α-amylase on MSP observed here and in earlier studies was related to the large probe (starch) being too large to adsorb in the pores, and potato starch has indeed a hydrodynamic diameter much larger than the pore sizes of MSPs. Further insights into the interactions and environments of the α-amylase inside the MSPs were provided by 1H fast magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and 13C/15N dynamic nuclear polarization MAS NMR experiments. It could be concluded that the overall fold and solvation of the α-amylase inside the MSPs were nearly identical to those in solution. 

Keywords
mesoporous silica particles, porcine pancreatic alpha-amylase, starch, 2-chloro-4-nitrophenyl alpha-d-maltotrioside (CNP-G3), (DNP) MAS NMR
National Category
Materials Chemistry Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-214591 (URN)10.1021/acsmaterialsau.3c00028 (DOI)001042090400001 ()2-s2.0-85168508459 (Scopus ID)
Available from: 2023-02-06 Created: 2023-02-06 Last updated: 2024-01-11Bibliographically approved
Gözcü, O., Kayacı, H. U., Dou, Y., Zhang, W., Hedin, N., Jasso-Salcedo, A. B., . . . Çınar Aygün, S. (2023). Colloidal Stabilization of Submicron-Sized Zeolite NaA in Ethanol–Water Mixtures for Nanostructuring into Thin Films and Nanofibers. Langmuir, 39(1), 192-203
Open this publication in new window or tab >>Colloidal Stabilization of Submicron-Sized Zeolite NaA in Ethanol–Water Mixtures for Nanostructuring into Thin Films and Nanofibers
Show others...
2023 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 39, no 1, p. 192-203Article in journal (Refereed) Published
Abstract [en]

Despite the growing use of organic or mixed solvents in zeolite processing, most studies focus only on aqueous suspension systems. We investigated the colloidal characteristics of submicron-sized zeolite NaA in mixed ethanol–water solvents. The effects of the mixing ratio of solvents and various additives on the dispersion of the zeolite powders were studied. The zeolite NaA particles were destabilized in solvent mixtures at a high ethanol-to-water ratio, a reduction in the zeta potential was observed, and the destabilization was rationalized by the Derjaguin, Landau, Verwey, Overbeek (DLVO) theory. An improved stabilization of the zeolite NaA suspensions was achieved in ethanol-rich solvent mixtures using nonionic low molecular weight organic additives, but not with their ionic counterparts such as anionic, cationic surfactants or inorganic acids or bases. Polyethylene glycol (PEG)-400 was found to be a good dispersant for the submicron-sized zeolite NaA particles in the ethanol–water mixtures, which was attributed to its interaction with the zeolite surface, leading to an increased zeta potential. The PEG-stabilized zeolite suspensions led to low suspension viscosities as well as uniform and consistent spin-coated films. 

National Category
Chemical Sciences Materials Engineering
Identifiers
urn:nbn:se:su:diva-214496 (URN)10.1021/acs.langmuir.2c02241 (DOI)000903625600001 ()36537794 (PubMedID)2-s2.0-85144417821 (Scopus ID)
Available from: 2023-02-07 Created: 2023-02-07 Last updated: 2023-02-07Bibliographically approved
Shu, C., Zhao, M., Cheng, H., Deng, Y., Stiernet, P., Hedin, N. & Yuan, J. (2023). Desulfurization of diesel via joint adsorption and extraction using a porous liquid derived from ZIF-8 and a phosphonium-type ionic liquid. Reaction Chemistry & Engineering (12), 3124-3132
Open this publication in new window or tab >>Desulfurization of diesel via joint adsorption and extraction using a porous liquid derived from ZIF-8 and a phosphonium-type ionic liquid
Show others...
2023 (English)In: Reaction Chemistry & Engineering, ISSN 2058-9883, no 12, p. 3124-3132Article in journal (Refereed) Published
Abstract [en]

A type-III porous liquid based on zeolitic imidazolate framework-8 (ZIF-8) and an ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([THTDP][BTI]) was synthesized and used for the desulfurization of model diesel. The desulfurization effect by ZIF-8/[THTDP][BTI] combined both the adsorptive desulfurization by ZIF-8 and the extraction desulfurization by [THTDP][BTI]. The removal of the three chosen aromatic organic sulfides by the ZIF-8/[THTDP][BTI] porous liquid followed the order of dibenzothiophene (73.1%) > benzothiophene (70.0%) > thiophene (61.5%). It was further found that deep desulfurization could be realized by ZIF-8/[THTDP][BTI] through triple desulfurization cycles and ZIF-8/[THTDP][BTI] can be regenerated readily. The desulfurization mechanism was explored further in detail by conformation search and density functional theory calculations. Calculations supported that the large molecular volume of [THTDP][BTI] excluded itself from the cavities of ZIF-8, making the pores of ZIF-8 in the porous liquid unoccupied and accessible by other guest species, here the studied organic sulfides. These calculations indicate that the van der Waals interactions were the main interactions between ZIF-8/[THTDP][BTI] and specifically benzothiophene. This work supports that the porous liquid ZIF-8/[THTDP][BTI] could potentially be used for desulfurization of diesel in industry.

National Category
Physical Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-222203 (URN)10.1039/d3re00364g (DOI)001064636200001 ()2-s2.0-85170696745 (Scopus ID)
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2024-01-12Bibliographically approved
Huang, Q., Zhao, Z., Zhao, X., Li, Q., Liu, H., Lu, H., . . . Zhao, D. (2023). Effective photocatalytic sterilization based on composites of Ag/InVO4/BiOBr: Factors, mechanism and application. Separation and Purification Technology, 327, Article ID 125011.
Open this publication in new window or tab >>Effective photocatalytic sterilization based on composites of Ag/InVO4/BiOBr: Factors, mechanism and application
Show others...
2023 (English)In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 327, article id 125011Article in journal (Refereed) Published
Abstract [en]

We hypothesized that photocatalysts with a low band gap could be useful in the sterilization of ceramic tiles in the natural environments of toilets using natural light in those settings. Certain photocatalysts can produce reactive oxygen species (ROS) under light illumination, which in turn are bactericidal. The properties of the BiOBr-containing photocatalysts were tuned by creating junctions and heterostructures with Ag and InVO4 and studied with respect to their bactericidal effect in dispersion. The bactericidal mechanism was studied through experiments in which active species were captured and via electron paramagnetic resonance (EPR) spectroscopy. At an optimal dosage of 0.5 g/L, the Ag/InVO4/BiOBr composite had a sterilization efficacy of 99.9999 % in 30 min under visible light illumination of 1000 W. It retained a sterilization efficacy of 99.999 % after four cycles. Anions such as Cl, SO42−, and NO3 were shown to have no negative impact on sterilization efficacy. It was shown that the holes in the composite photocatalyst and hydroxyl radicals (·OH) were mechanistically critical for the sterilization. The photocatalysts were also studied in the field in the natural environment of a restroom, where they were loaded on ceramic tiles. Samples were collected from the surface of the ceramic tiles and analyzed for bacterial cultures and microbial diversity. The results were compared in the scope of the sterilization ability of various agents at the microbial level. The ceramic tiles loaded with Ag/InVO4/BiOBr showed the least amount of bacteria on their surfaces, and the microbial community richness was also the lowest.

Keywords
Silver, Bismuth Oxybromide, Indium Vanadate, Photocatalysis, Sterilization
National Category
Chemical Process Engineering Materials Chemistry
Identifiers
urn:nbn:se:su:diva-223448 (URN)10.1016/j.seppur.2023.125011 (DOI)001078422700001 ()2-s2.0-85171684268 (Scopus ID)
Available from: 2023-10-31 Created: 2023-10-31 Last updated: 2023-10-31Bibliographically approved
Iqbal, M. N., Robert-Nicoud, G., Ciurans-Oset, M., Akhtar, F., Hedin, N. & Bengtsson, T. (2023). Mesoporous Silica Particles Retain Their Structure and Function while Passing through the Gastrointestinal Tracts of Mice and Humans. ACS Applied Materials and Interfaces
Open this publication in new window or tab >>Mesoporous Silica Particles Retain Their Structure and Function while Passing through the Gastrointestinal Tracts of Mice and Humans
Show others...
2023 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, , p. 12Article in journal (Refereed) Published
Abstract [en]

Mesoporous silica particles (MSPs) can be used as food additives, clinically for therapeutic applications, or as oral delivery vehicles. It has also been discussed to be used for a number of novel applications including treatment for diabetes and obesity. However, a major question for their possible usage has been if these particles persist structurally and retain their effect when passing through the gastrointestinal tract (GIT). A substantial breaking down of the particles could reduce function and be clinically problematic for safety issues. Hence, we investigated the biostability of MSPs of the SBA-15 kind prepared at large scales (100 and 1000 L). The MSPs were orally administered in a murine model and clinically in humans. A joint extraction and calcination method was developed to recover the MSPs from fecal mass, and the MSPs were characterized physically, structurally, morphologically, and functionally before and after GIT passage. Analyses with N2 adsorption, X-ray diffraction, electron microscopy, and as a proxy for general function, adsorption of the enzyme α-amylase, were conducted. The adsorption capacity of α-amylase on extracted MSPs was not reduced as compared to the pristine and control MSPs, and adsorption of up to 17% (w/w) was measured. It was demonstrated that the particles did not break down to any substantial degree and retained their function after passing through the GITs of the murine model and in humans. The fact the particles were not absorbed into the body was ascribed to that they were micron-sized and ingested as agglomerates and too big to pass the intestinal barrier. The results strongly suggest that orally ingested MSPs can be used for a number of clinical applications. 

Publisher
p. 12
Keywords
mesoporous silica particles, biostability, gastrointestinal tract, protein adsorption, porcine pancreatic α-amylase
National Category
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-214588 (URN)10.1021/acsami.2c16710 (DOI)000928638000001 ()2-s2.0-85147567459 (Scopus ID)
Available from: 2023-02-06 Created: 2023-02-06 Last updated: 2023-04-21Bibliographically approved
Kausar, H., Bacsik, Z. & Hedin, N. (2023). Ultramicroporous polyureas synthesized with amines and 1,1′-Carbonyldiimidazole and their CO2 adsorption. Materials Chemistry and Physics, 296, Article ID 127283.
Open this publication in new window or tab >>Ultramicroporous polyureas synthesized with amines and 1,1′-Carbonyldiimidazole and their CO2 adsorption
2023 (English)In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 296, article id 127283Article in journal (Refereed) Published
Abstract [en]

Microporous polyureas can be highly stable, but isocyanates or phosgene are normally used for the synthesis. Here, it was postulated and demonstrated that 1,1′-carbonyl diimidazole (CDI) could be used for the synthesis. By reacting tetrakis(4-aminophenyl)methane with CDI, a series of new polyureas with ultramicropores (pores <0.7 nm) were synthesized. To tailor thermal properties and porosity, the ratio of tetraamine-to-CDI and the reaction temperature were varied. The CO2 adsorption capacities (with values up to 0.74 mmol/g at 0.15 bar/273 K and 1.91 mmol/g at 1 bar/273 K) were ascribed to the ultramicroporosity. The CO2-based Dubinin-Radushkevich surface areas reached 395 m2/g (at 273 K), while the N2-based BET surface areas (at 77 K) were small. The apparent CO2-over-N2 selectivity was also high for the polymers at 273 K with estimated values of 31–92 for 15/85 v/v mixtures of CO2 and N2. This high selectivity was ascribed to the kinetic hindrance of N2 diffusion. It was noted that one of the polymers changed color irreversibly upon heating. In conclusion, it was shown that CDI and amines could be used to synthesize ultramicroporous polyureas, and that these polymers can exhibit irreversible thermochromism. This thermal effect was attributed to the electron-rich urea moieties, aromatic units, and conjugation.

Keywords
1, 1′-carbonyl diimidazole, Urea-linked, CO2/N2 selectivity, Ultramicropores, Thermochromism
National Category
Materials Engineering
Identifiers
urn:nbn:se:su:diva-215290 (URN)10.1016/j.matchemphys.2022.127283 (DOI)000920831600001 ()2-s2.0-85145782103 (Scopus ID)
Available from: 2023-03-14 Created: 2023-03-14 Last updated: 2023-03-14Bibliographically approved
Di Francesco, D., Rigo, D., Baddigam, K. R., Mathew, A. P., Hedin, N., Selva, M. & Samec, J. S. M. (2022). A New Family of Renewable Thermosets: Kraft Lignin Poly-adipates. ChemSusChem, 15(11), Article ID e202200326.
Open this publication in new window or tab >>A New Family of Renewable Thermosets: Kraft Lignin Poly-adipates
Show others...
2022 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 15, no 11, article id e202200326Article in journal (Refereed) Published
Abstract [en]

Thermosetting polymeric materials have advantageous properties and are therefore used in numerous applications. In this study, it was hypothesized and ultimately shown that thermosets could be derived from comparably sustainable sub-components. A two-step procedure to produce a thermoset comprising of Kraft lignin (KL) and the cross-linker adipic acid (AdA) was developed. The cross-linking was activated by means of an acetylating agent comprising isopropenyl acetate (IPA) to form a cross-linking mixture (CLM). The cross-linking was confirmed by FTIR and solid-state NMR spectroscopy, and the esterification reactions were further studied using model compounds. When the KL lignin was mixed with the CLM, partial esterification occurred to yield a homogeneous viscous liquid that could easily be poured into a mold, as the first step in the procedure. Without any additions, the mold was heated and the material transformed into a thermoset by reaction of the two carboxylic acid-derivatives of AdA and KL in the second step.

Keywords
adipic acid, bioplastics, lignin, renewable materials, thermosets
National Category
Chemical Engineering
Identifiers
urn:nbn:se:su:diva-204767 (URN)10.1002/cssc.202200326 (DOI)000788650400001 ()35312238 (PubMedID)2-s2.0-85129013402 (Scopus ID)
Available from: 2022-05-19 Created: 2022-05-19 Last updated: 2022-06-10Bibliographically approved
Hsini, N., Saadattalab, V., Wang, X., Gharred, N., Dhaouadi, H., Dridi-Dhaouadi, S. & Hedin, N. (2022). Activated Carbons Produced from Hydrothermally Carbonized Prickly Pear Seed Waste. Sustainability, 14(21), Article ID 14559.
Open this publication in new window or tab >>Activated Carbons Produced from Hydrothermally Carbonized Prickly Pear Seed Waste
Show others...
2022 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 21, article id 14559Article in journal (Refereed) Published
Abstract [en]

The agro-sector generates organic waste of various kinds, which potentially could be used to prepare functional materials, lessen environmental problems, and enhance circularity. In this context, the hypothesis that was put forward in this work is that prickly pear seed waste from the Tunisian agro-food industry could be used to prepare activated carbons. The prickly pear seed waste was first hydrothermally carbonized and the resulting hydrochar was activated in CO2 at 800 °C. The yield of the hydrothermal carbonization process is of importance, and it was the highest at intermediate dwell times and temperatures, which was ascribed to the re-precipitation of hydrochar particles on the heat-treated biomass. The hydrochars and activated carbons were characterized with scanning electron microscopy, thermogravimetry, Raman spectroscopy, and N2 and CO2 adsorption/desorption analyses. The activated carbons had micro- (<2 nm) and mesopores (2–50 nm), and specific surface areas and total pore volumes of about 400 m2 −1 and 0.21 cm3 g−1. The study showed that the prickly pear seed waste could be effectively transformed into both hydrochars and activated carbons and that is advisable to optimize the hydrothermal process for the mass yield. A life cycle analysis was performed to assess the environmental impact of the production of typical activated carbons using the approach of this study. Further studies could be focused on enhancing the properties of the activated carbons by further optimization of the activation process.

Keywords
bio-waste, prickly pear seeds, hydrothermal carbonization, activated carbons, CO2 activation, life cycle assessment, Green & Sustainable Science & Technology
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-212591 (URN)10.3390/su142114559 (DOI)000885860700001 ()
Available from: 2022-12-13 Created: 2022-12-13 Last updated: 2023-01-13Bibliographically approved
Saadattalab, V., Jansson, K., Tai, C. W. & Hedin, N. (2022). Blue hydrochars formed on hydrothermal carbonization of glucose using an iron catalyst. Carbon Trends, 8, Article ID 100172.
Open this publication in new window or tab >>Blue hydrochars formed on hydrothermal carbonization of glucose using an iron catalyst
2022 (English)In: Carbon Trends, ISSN 2667-0569, Vol. 8, article id 100172Article in journal (Refereed) Published
Abstract [en]

We hypothesized that the morphology of the hydrochar from hydrothermal carbonization of glucose would be affected by Fe2+; and indeed, with such ions, large pieces of hydrochar formed that comprised aggregated spherical particles and blue and thin films. Thin carbonized films formed at the bottom of the autoclave liners or on TeflonTM tape used as a template. Free-standing films could be prepared by stretching the TeflonTM tape after the synthesis. The carbonized films that formed at the bottom of the autoclave adhered to spherical hydrochar particles. The blueness was ascribed to thin-film interference under white-light irradiation and related to the film thickness, which was about 200 nm. Analysis of transmission electron microscopy (TEM) images showed that the films consisted of a layered amorphous carbon. The amorphous and thin films were more carbonized than the amorphous carbon of the TEM grid, as derived via electron energy loss spectroscopy (EELS). Additional analysis of one of the thin films by X-ray photoelectron spectral analysis showed a higher carbon fraction than for bulk hydrochar, supporting the EELS analysis. We believe that the synthesis of thin films of hydrochar can open up new colloidal processing pathways, which could be useful in the preparation of carbon-based materials and alike.

Keywords
Hydrothermal carbonization, Glucose, Iron sulfate, Carbon spheres, Thin films, Thin film interference
National Category
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-206189 (URN)10.1016/j.cartre.2022.100172 (DOI)2-s2.0-85128535062 (Scopus ID)
Funder
Mistra - The Swedish Foundation for Strategic Environmental Research, 2015/31
Available from: 2022-06-22 Created: 2022-06-22 Last updated: 2023-04-19Bibliographically approved
Zhou, X., Yan, F., Lyubartsev, A. P., Shen, B., Zhai, J., Conesa, J. C. & Hedin, N. (2022). Efficient Production of Solar Hydrogen Peroxide Using Piezoelectric Polarization and Photoinduced Charge Transfer of Nanopiezoelectrics Sensitized by Carbon Quantum Dots. Advanced Science, 9(18), Article ID 2105792.
Open this publication in new window or tab >>Efficient Production of Solar Hydrogen Peroxide Using Piezoelectric Polarization and Photoinduced Charge Transfer of Nanopiezoelectrics Sensitized by Carbon Quantum Dots
Show others...
2022 (English)In: Advanced Science, E-ISSN 2198-3844, Vol. 9, no 18, article id 2105792Article in journal (Refereed) Published
Abstract [en]

Piezoelectric semiconductors have emerged as redox catalysts, and challenges include effective conversion of mechanical energy to piezoelectric polarization and achieving high catalytic activity. The catalytic activity can be enhanced by simultaneous irradiation of ultrasound and light, but the existing piezoelectric semiconductors have trouble absorbing visible light. A piezoelectric catalyst is designed and tested for the generation of hydrogen peroxide (H2O2). It is based on Nb-doped tetragonal BaTiO3 (BaTiO3:Nb) and is sensitized by carbon quantum dots (CDs). The photosensitizer injects electrons into the conduction band of the semiconductor, while the piezoelectric polarization directed electrons to the semiconductor surface, allowing for a high-rate generation of H2O2. The piezoelectric polarization field restricts the recombination of photoinduced electron–hole pairs. A production rate of 1360 µmol gcatalyst−1 h−1 of H2O2 is achieved under visible light and ultrasound co-irradiation. Individual piezo- and photocatalysis yielded lower production rates. Furthermore, the CDs enhance the piezocatalytic activity of the BaTiO3:Nb. It is noted that moderating the piezoelectricity of BaTiO3:Nb via microstructure modulation influences the piezophotocatalytic activity. This work shows a new methodology for synthesizing H2O2 by using visible light and mechanical energy.

Keywords
carbon quantum dots, hydrogen peroxide, Nb-doped BaTiO3, piezocatalysis, piezoelectric polarization, piezophotocatalysis
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-204410 (URN)10.1002/advs.202105792 (DOI)000786488600001 ()35451215 (PubMedID)2-s2.0-85128574371 (Scopus ID)
Available from: 2022-05-04 Created: 2022-05-04 Last updated: 2022-08-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7284-2974

Search in DiVA

Show all publications