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Leandri, V., Gardner, J. M. & Jonsson, M. (2019). Coumarin as a Quantitative Probe for Hydroxyl Radical Formation in Heterogeneous Photocatalysis. The Journal of Physical Chemistry C, 123(11), 6667-6674
Open this publication in new window or tab >>Coumarin as a Quantitative Probe for Hydroxyl Radical Formation in Heterogeneous Photocatalysis
2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 11, p. 6667-6674Article in journal (Refereed) Published
Abstract [en]

In this work, we have assessed coumarin as a quantitative probe for hydroxyl radical formation in heterogeneous photocatalysis. Upon reaction with the hydroxyl radical, coumarin produces several hydroxylated products, of which one, 7-OH-coumarin, is strongly fluorescent. The fluorescence emission is strongly affected by inner filtering due to the presence of coumarin. Therefore, we performed a series of calibration experiments to correct for the coumarin concentration. From the calibration experiments, we could verify that the inner-filtering effect can be attributed to the competing absorption of the fluorescence excitation light between coumarin and 7-OH-coumarin. Through judicious calibration for the inner-filtering effects, the corrected results for the photocatalytic system show that the rate of hydroxyl scavenging is constant with time for initial coumarin concentrations of ≥50 μM under the conditions of our experiments. The rate increases linearly with coumarin concentration, as expected from the Langmuir–Hinshelwood model. Within the coumarin concentration range used here, the photocatalyst surface does not become saturated. Given the fact that the highest coumarin concentration used (1 mM) in this work is quite close to the solubility limit, we conclude that coumarin cannot be used to assess the full photocatalytic capacity of the system, i.e., surface saturation is never reached. The rate of hydroxyl radical scavenging will, to a large extent, depend on the affinity to the surface, and it is therefore not advisable to use coumarin as a probe for photocatalytic efficiency when comparing different photocatalysts.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-249493 (URN)10.1021/acs.jpcc.9b00337 (DOI)000462260700040 ()2-s2.0-85062883293 (Scopus ID)
Note

QC 20190426

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2019-04-26Bibliographically approved
Toijer, E. & Jonsson, M. (2019). H 2 O 2 and γ-radiation induced corrosion of 304L stainless steel in aqueous systems. Radiation Physics and Chemistry, 159, 159-165
Open this publication in new window or tab >>H 2 O 2 and γ-radiation induced corrosion of 304L stainless steel in aqueous systems
2019 (English)In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 159, p. 159-165Article in journal (Refereed) Published
Abstract [en]

In light-water reactors the water used as neutron moderator and coolant is subjected to a constant radiation field which leads to the formation of a number of oxidizing and reducing species. In this work, the reactivity of the radiolysis product H 2 O 2 towards the 304L alloy, commonly used for structural materials in nuclear power plants, was investigated as well as oxidative dissolution of steel components as a consequence of γ-radiation and chemically added H 2 O 2 . The concentration of hydrogen peroxide as a function of time was monitored in the presence of different amounts of steel powder, and the second order reaction rate constant was determined to k 2 = (1.8 ± 0.2) × 10 −10 m s −1 . In the case of catalytic decomposition of hydrogen peroxide, hydroxyl radicals are formed which can be scavenged by methanol. In this reaction formaldehyde is formed, which can be detected spectroscopically. A high yield of formaldehyde was observed, indicating that catalytic decomposition is the main reaction path of H 2 O 2 in the current system. A significant contribution of the homogeneous Fenton reaction to both the reaction rate constant and the formaldehyde formation must however be considered, as Fe(II) will be released from the oxide layer in solution. In the case of γ-irradiation, an increased nickel content in solution compared to background experiments is seen. When the steel is subjected to chemically added hydrogen peroxide on the other hand, the chromium content in solution is increased. This indicates that the different types of exposure will impact different parts of the oxide layer characterized by different composition. © 2019

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Formaldehyde, Gamma rays, Hydrogen peroxide, Iron compounds, Light water reactors, Neutron irradiation, Nuclear fuels, Nuclear power plants, Oxidation, Peroxides, Radiation chemistry, Rate constants, Steel corrosion, 304L stainless steel, Catalytic decomposition, Gamma irradiation, Neutron moderators, Oxidative dissolution, Radiation-induced, Radiolysis products, Second-order reaction, Austenitic stainless steel, chromium, hydroxyl radical, methanol, nickel, stainless steel, Article, corrosion, decomposition, dissolution, Fenton reaction, radiolysis, surface area
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-252508 (URN)10.1016/j.radphyschem.2019.02.047 (DOI)000472690000022 ()2-s2.0-85062715868 (Scopus ID)
Note

QC 20190711

Available from: 2019-07-11 Created: 2019-07-11 Last updated: 2019-07-11Bibliographically approved
Chen, S., Abdel-Magied, A. F., Fu, L., Jonsson, M. & Forsberg, K. (2019). Incorporation of strontium and europium in crystals of α-calcium isosaccharinate. Journal of Hazardous Materials, 364, 309-316
Open this publication in new window or tab >>Incorporation of strontium and europium in crystals of α-calcium isosaccharinate
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2019 (English)In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 364, p. 309-316Article in journal (Refereed) Published
Abstract [en]

The final repository for short-lived, low and intermediate level radioactive waste in Sweden is built to act as a passive repository. Already within a few years after closure water will penetrate the repository and conditions of high alkalinity (pH 10.5―13.5) and low temperature (< 7 °C) will prevail. The mobility of radionuclides in the repository is dependent on the radionuclides distribution between solid and liquid phases. In the present work the incorporation of strontium (II) and europium (III) in α-calcium isosaccharinate (ISA) under alkaline conditions (pH ~10) at 5 °C and 50 °C have been studied. The results show that strontium and europium are incorporated into α-Ca(ISA)2 when crystallized both at 5 °C and 50 °C. Europium is incorporated to a greater extent than strontium. The highest incorporation of europium and strontium at 5 °C rendered the phase compositions Ca0.986Eu0.014(ISA)2 (2.4% of Eu(ISA)3 by mass) and Ca0.98Sr0.02(ISA)2 (2.2% of Sr(ISA)2 by mass). XPS spectra show that both trivalent and divalent Eu coexist in the Eu incorporated samples. Strontium ions were found to retard the elongated growth of the Ca(ISA)2crystals. The incorporation of Sr2+ and Eu3+ into the solid phase of Ca(ISA)2 is expected to contribute to a decreased mobility of these ions in the repository.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Mobility, radionuclides, isosaccharinate, precipitation
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-235920 (URN)10.1016/j.jhazmat.2018.10.001 (DOI)000452926500034 ()30384240 (PubMedID)2-s2.0-85055549831 (Scopus ID)
Funder
Swedish Radiation Safety Authority, SSM2016-2126
Note

QC 20181010

Available from: 2018-10-08 Created: 2018-10-08 Last updated: 2019-05-20Bibliographically approved
Dahlgren, B., Dispenza, C. & Jonsson, M. (2019). Numerical Simulation of the Kinetics of Radical Decay in Single-Pulse High-Energy Electron-Irradiated Polymer Aqueous Solutions. Journal of Physical Chemistry A, 123(24), 5043-5050
Open this publication in new window or tab >>Numerical Simulation of the Kinetics of Radical Decay in Single-Pulse High-Energy Electron-Irradiated Polymer Aqueous Solutions
2019 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, no 24, p. 5043-5050Article in journal (Refereed) Published
Abstract [en]

A new method for the numerical simulation of the radiation chemistry of aqueous polymer solutions is introduced. The method makes use of a deterministic approach combining the conventional homogeneous radiation chemistry of water with the chemistry of polymer radicals and other macromolecular species. The method is applied on single-pulse irradiations of aqueous polymer solutions. The speciation of macromolecular species accounts for the variations in the number of alkyl radicals per chain, molecular weight, and number of internal loops (as a consequence of an intramolecular radical-radical combination). In the simulations, the initial polymer molecular weight, polymer concentration, and dose per pulse (function of pulse length and dose rate during the pulse) were systematically varied. In total, 54 different conditions were simulated. The results are well in line with the available experimental data for similar systems. At a low polymer concentration and a high dose per pulse, the kinetics of radical decay is quite complex for the competition between intra- and intermolecular radical-radical reactions, whereas at a low dose per pulse the kinetics is purely second-order. The simulations demonstrate the limitations of the polymer in scavenging all the radicals generated by water radiolysis when irradiated at a low polymer concentration and a high dose per pulse. They also show that the radical decay of lower-molecular-weight chains is faster and to a larger extent dominated by intermolecular radical-radical reactions, thus explaining the mechanism behind the experimentally observed narrowing of molecular weight distributions.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-255441 (URN)10.1021/acs.jpca.9b03013 (DOI)000472800600005 ()31140810 (PubMedID)2-s2.0-85067854545 (Scopus ID)
Note

QC 20190812

Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Barreiro Fidalgo, A. & Jonsson, M. (2019). Radiation induced dissolution of (U, Gd)O-2 pellets in aqueous solution - A comparison to standard UO2 pellets. Journal of Nuclear Materials, 514, 216-223
Open this publication in new window or tab >>Radiation induced dissolution of (U, Gd)O-2 pellets in aqueous solution - A comparison to standard UO2 pellets
2019 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 514, p. 216-223Article in journal (Refereed) Published
Abstract [en]

The behavior of spent nuclear fuel exposed to groundwater is crucial in the safety assessment of a deep geological repository for spent nuclear fuel. For this reason, leaching experiments on spent nuclear fuel as well as non-radioactive analogues have been conducted for several decades. Although the processes involved can be considered to be fairly well understood, there is a need for further experimental studies whenever new fuel types are introduced. Fuels with burnable absorbers are now in use but very little is known about their behavior under repository conditions. In this work, the impact of burnable absorbers doping (Gd, 3-8%wt.) on the oxidative dissolution of UO2 in an aqueous system was studied in H2O2 and gamma-irradiation induced dissolution experiments. The results showed a significant decrease in uranium dissolution and lower reactivity towards H2O2 for (U,Gd)O-2 pellets compared to standard UO2. The resulting decrease in the final oxidative dissolution yield was mainly attributed to decreased redox reactivity of the UO2-matrix upon doping. The results of the gamma radiation exposures display an even larger effect of Gd-doping. These findings indicate that other processes are involved in the radiation-induced dissolution of Gd-doped UO2 compared to pure UO2. 

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-241303 (URN)10.1016/j.jnucmat.2018.11.037 (DOI)000454829000025 ()2-s2.0-85057718007 (Scopus ID)
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-04-09Bibliographically approved
Ditta, L. A., Dahlgren, B., Sabatino, M. A., Dispenza, C. & Jonsson, M. (2019). The role of molecular oxygen in the formation of radiation-engineered multifunctional nanogels. European Polymer Journal, 114, 164-175
Open this publication in new window or tab >>The role of molecular oxygen in the formation of radiation-engineered multifunctional nanogels
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2019 (English)In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 114, p. 164-175Article in journal (Refereed) Published
Abstract [en]

Nanogels are very promising biomedical nanodevices. The classic “radiation chemistry-based” approach to synthetize nanogels consists in the irradiation with pulsed electron beams of dilute, N 2 O-saturated, aqueous solutions of water-soluble polymers of the “crosslinking type”. Nanogels with controlled size and properties are produced in a single irradiation step with no recourse to initiators, organic solvents and surfactants. This paper combines experimental syntheses, performed with two e-beam irradiation setups and dose-ranges, starting from poly(N-vinyl pyrrolidone) solutions of various concentrations, both in N 2 O-saturated and air-saturated initial conditions, with the numerical simulations of the radiation chemistry of aqueous solutions of a radical scavanger exposed to the same irradiation conditions used in the experiments. This approach provides a methodology to predict the impact of system and irradiation conditions on the water radiation chemistry, which in turn affect the nanogel features in terms of molecular and physico-chemical properties. In particular, the crucial role of initial and transient concentration of molecular oxygen is revealed. This work also proposes a very simple and effective methodology to quantitatively measure the double bonds formed in the systems from disporportionation and chain scission reactions, competing with inter-/intra-molecular crosslinking.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Crosslinking, Kinetic modeling, Mechanism, Nanogel, Water radiolysis
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-246432 (URN)10.1016/j.eurpolymj.2019.02.020 (DOI)000467668800019 ()2-s2.0-85062017202 (Scopus ID)
Note

QC 20190329

Available from: 2019-03-29 Created: 2019-03-29 Last updated: 2019-06-11Bibliographically approved
Chernyshev, A. N., Jonsson, M. & Forsberg, K. (2018). Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories. Applied Geochemistry, 95, 172-181
Open this publication in new window or tab >>Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories
2018 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 95, p. 172-181Article in journal (Refereed) Published
Abstract [en]

Superplasticizers are important additives used in concrete barriers in geological waste repositories. Superplasticizers have been a major concern in the long-term assessments of safe geological disposal for radioactive waste since superplasticizers and their degradation products can act as complexing ligands and thereby increase the mobility of radionuclides. In this work a new type of superplasticizer, based on a polyaryl ether polymer, has been characterized. It was found that the superplasticizer combines the structural features of polycarboxylate ether based superplasticizers and sulfonated naphthalene-formaldehyde based superplasticizers and that it contains organophosphatecharged groups. A novel method for evaluating the rate of degradation of the superplasticizer under alkaline conditions was elaborated and the degradation products and rate constant of the process was determined. The results demonstrate that degradation occurs rapidly compared to the typical lifetime of a repository.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Waste disposal; Alkaline degradation; Polyaryl ether based superplasticizer
National Category
Chemical Engineering Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-228236 (URN)10.1016/j.apgeochem.2018.05.014 (DOI)000437294900015 ()2-s2.0-85048180279 (Scopus ID)
Funder
Swedish Nuclear Fuel and Waste Management Company, SKB
Note

QC 20180611

Available from: 2018-05-20 Created: 2018-05-20 Last updated: 2018-11-28Bibliographically approved
Li, Z., Soroka, I., Min, F. & Jonsson, M. (2018). pH-Control as a way to fine-tune the Cu/Cu2O ratio in radiation induced synthesis of Cu2O particles. Dalton Transactions, 47(45), 16139-16144
Open this publication in new window or tab >>pH-Control as a way to fine-tune the Cu/Cu2O ratio in radiation induced synthesis of Cu2O particles
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 45, p. 16139-16144Article in journal (Refereed) Published
Abstract [en]

In this work we have optimized the -radiation induced synthesis of Cu-Cu2O particles from aqueous CuSO4 solution by investigating the effect of pH. The obtained precipitate was analyzed by XRD and SEM techniques. The results indicated that at solution pH lower than 3.75, quasi-spherical Cu agglomerates can be formed while at pH higher than 4.40 only octahedron-shaped Cu2O particles are produced. At solution pH in the range from 3.75 to 4.40, a Cu-Cu2O mixture is produced. It was found that the relative amount of Cu2O in the Cu-Cu2O precipitate increases with pH in the studied range. The influence of solution pH on the Cu/Cu2O ratios in the product can be explained on the basis of pH-dependent competition kinetics between the reactions leading to either Cu or Cu2O formation. As a consequence, the composition and morphology of the Cu-Cu2O precipitate can be tuned by controlling pH of the aqueous CuSO4 solution during the -radiation induced synthesis.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-240347 (URN)10.1039/c8dt02916d (DOI)000451018400017 ()30378612 (PubMedID)2-s2.0-85056968525 (Scopus ID)
Note

QC 20181217

Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-04-08Bibliographically approved
Seashore-Ludlow, B., Axelsson, H., Almqvist, H., Dahlgren, B., Jonsson, M. & Lundback, T. (2018). Quantitative Interpretation of Intracellular Drug Binding and Kinetics Using the Cellular Thermal Shift Assay. Biochemistry, 57(48), 6715-6725
Open this publication in new window or tab >>Quantitative Interpretation of Intracellular Drug Binding and Kinetics Using the Cellular Thermal Shift Assay
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2018 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 57, no 48, p. 6715-6725Article in journal (Refereed) Published
Abstract [en]

Evidence of physical interaction with the target protein is essential in the development of chemical probes and drugs. The cellular thermal shift assay (CETSA) allows evaluation of drug binding in live cells but lacks a framework to support quantitative interpretations and comparisons with functional data. We outline an experimental platform for such analysis using human kinase p38 alpha. Systematic variations to the assay's characteristic heat challenge demonstrate an apparent loss of compound potency with an increase in duration or temperature, in line with expectations from the literature for thermal shift assays. Importantly, data for five structurally diverse inhibitors can be quantitatively explained using a simple model of linked equilibria and published binding parameters. The platform further distinguishes between ligand mechanisms and allows for quantitative comparisons of drug binding affinities and kinetics in live cells and lysates. We believe this work has broad implications in the appropriate use of the CETSA for target and compound validation.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-240736 (URN)10.1021/acs.biochem.8b01057 (DOI)000452693000009 ()30418016 (PubMedID)2-s2.0-85057521293 (Scopus ID)
Funder
Swedish Research CouncilScience for Life Laboratory - a national resource center for high-throughput molecular bioscience
Note

QC 20190108

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-01-08Bibliographically approved
Norrfors, K. K., Björkbacka, Å., Kessler, A., Wold, S. & Jonsson, M. (2018). γ-radiation induced corrosion of copper in bentonite-water systems under anaerobic conditions. Radiation Physics and Chemistry, 144, 8-12
Open this publication in new window or tab >>γ-radiation induced corrosion of copper in bentonite-water systems under anaerobic conditions
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2018 (English)In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 144, p. 8-12Article in journal (Refereed) Published
Abstract [en]

In this work we have experimentally studied the impact of bentonite clay on the process of radiation-induced copper corrosion in anoxic water. The motivation for this is to further develop our understanding of radiation-driven processes occurring in deep geological repositories for spent nuclear fuel where copper canisters containing the spent nuclear fuel will be embedded in compacted bentonite. Experiments on radiation-induced corrosion in the presence and absence of bentonite were performed along with experiments elucidating the impact irradiation on the Cu2+ adsorption capacity of bentonite. The experiments presented in this work show that the presence of bentonite clay has no or very little effect on the magnitude of radiation-induced corrosion of copper in anoxic aqueous systems. The absence of a protective effect similar to that observed for radiation-induced dissolution of UO2 is attributed to differences in the corrosion mechanism. This provides further support for the previously proposed mechanism where the hydroxyl radical is the key radiolytic oxidant responsible for the corrosion of copper. The radiation effect on the bentonite sorption capacity of Cu2+ (reduced capacity) is in line with what has previously been reported for other cations. The reduced cation sorption capacity is partly attributed to a loss of Al-OH sites upon irradiation.

Place, publisher, year, edition, pages
Elsevier Ltd, 2018
Keywords
Aluminum compounds, Anoxic sediments, Copper, Copper corrosion, Corrosion, Irradiation, Positive ions, Radiation, Adsorption capacities, Anaerobic conditions, Compacted bentonite, Corrosion mechanisms, Deep geological repository, Protective effects, Sorption capacities, Spent nuclear fuels, Bentonite, hydroxyl radical, nuclear fuel, adsorption kinetics, anaerobic capacity, Article, embedding, environmental impact assessment, gamma radiation, water supply
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-223137 (URN)10.1016/j.radphyschem.2017.11.004 (DOI)000423646400002 ()2-s2.0-85034661878 (Scopus ID)
Funder
Swedish Nuclear Fuel and Waste Management Company, SKB
Note

Export Date: 13 February 2018; Article; CODEN: RPCHD; Correspondence Address: Jonsson, M.; School of Chemical Science and Engineering, Applied Physical Chemistry, KTH Royal Institute of TechnologySweden; email: matsj@kth.se; Funding details: SKB, Svensk Kärnbränslehantering. QC 20180326

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-03-26Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0663-0751

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