RSC Advances Blog

We are very pleased to introduce John McGrady, corresponding author, and his co-authors of the paper ‘The kinetics and mechanism of H₂O₂ decomposition at the U₃O₈ surface in bicarbonate solution‘. Their article has been very well received and handpicked by our reviewers and handling editors as one of our HOT articles. John told us more about the work that went into this article and what he hopes to achieve in the future. You can find out more about the authors and their article below and find more HOT articles in our online collection.

Meet the authors

	Dr John McGrady received an EngD in Nuclear Engineering from the University of Manchester in 2017. He is currently working as a Special Topic Researcher at the Nuclear Science and Engineering Center, Japan Atomic Energy Agency (JAEA) and as a postdoctoral researcher at the University of Tokyo. His research focuses on the solid/liquid interface for applications in nuclear plant processes and nuclear waste disposal.
	Dr Masayuki Watanabe is a Division Head of Nuclear Chemistry Division, Nuclear Science and Engineering Center, Japan Atomic Energy Agency. He received his DSci in chemistry from Tokyo University. His research interests are coordination chemistry of actinides and lanthanides and is currently focused on the chemistry at solid-liquid and liquid-liquid interface.
	Dr Yuta Kumagai received his PhD degree from the School of Engineering, the University of Tokyo in 2011. He is currently an Associate Principal Researcher at the Nuclear Science and Engineering Center, Japan Atomic Energy Agency. His area of expertise is radiation chemistry and his recent research interest is radiation effects on solid-liquid systems.
	Dr Akira Kirishima is a Professor of Nuclear chemistry at Institute of Multidisciplinary Research for Advanced Materials, Tohoku University. He earned his PhD in Engineering from Graduate School of Engineering, Tohoku University. His field of specialization is solution chemistry of actinide and nuclear waste management. His research interests are recently focused on chemistry of nuclear fuel debris generated at the severe accident in Fukushima Daiichi Nuclear power plant in 2011.
	Dr Daisuke Akiyama is an assistant Prof. of Nuclear chemistry at Institute of Multidisciplinary Research for Advanced Materials, Tohoku University. He received his PhD in Engineering from Kyushu University (2014). His research interests are currently focused on the immobilization of radioactive waste generated from the Fukushima Daiichi Nuclear Power Plant.
	Dr Akira Kitamura received his PhD in Engineering from Osaka University, Japan in 1999. He was a principal researcher at Japan Atomic Energy Agency and dedicated to research on migration behaviour of radionuclides in engineered barrier systems for geological disposal of high-level radioactive waste and TRU waste. Currently he belongs to the Agency for Natural Resources and Energy in Ministry of Economy, Trade and Industry and is dedicated to promoting geological disposal programs in Japan through managing their technical basis.
	Dr Shingo Kimuro is a researcher at Japan Atomic Energy Agency. He earned his PhD in Engineering from Graduate School of Engineering, Tohoku University in 2018. His research topic is the assessment of the migration of radionuclides in deep underground environment, especially the effect of organic materials.

Could you briefly explain the focus of your article to the non-specialist (in one or two sentences only) and why it is of current interest?
A key issue in the nuclear industry today is the disposal methodology of nuclear waste, with the direct disposal of spent nuclear fuel in deep geological facilities being an alternative option in Japan. This article focusses on predicting the potential release of radioactive material via dissolution of uranium upon contact of spent nuclear fuel with groundwater.

How big an impact could your results potentially have?
This study determined that the water chemistry of groundwater has a significant effect on the dissolution rate of highly oxidised uranium (U3O8) waste. As groundwater chemistry varies depending on deep geological facility location, the observed effects of groundwater chemistry on waste dissolution have significant implications for safety case formulation regarding predictions of radionuclide release into the environment. The results from this study also showed that the mechanism of dissolution is highly dependent on the form of oxidised uranium within the spent fuel, showing that the composition of uranium waste will have a large bearing on uranium release.

Could you explain the motivation behind this study?
This study is part of a project being conducted in Japan regarding the development of the direct disposal method as an alternative option for the handling of spent nuclear fuel according to the present Japanese strategy. Currently, there is still a lack of knowledge regarding the mechanism of uranium dissolution from spent nuclear fuel and the effect of oxidants such as H₂O₂ on dissolution. Additionally, typical concentrations of bicarbonate in deep groundwater in Japan is over ten times higher than that of Western countries. Therefore, uranium dissolution with H₂O₂ as a function of bicarbonate has been investigated in this study.

In your opinion, what are the key design considerations for your study?
The key design consideration was how to simulate radiation effects to instigate the dissolution reactions. Radiation generated from decay of nuclides in nuclear waste will cause water radiolysis of groundwater and the formation of a number of oxidising species that affect dissolution. H₂O₂ was chosen as the main oxidant in this study, and as the concentration of H₂O₂ generated by nuclear waste induced radiolysis will depend on the lifetime of the waste, the concentration of H₂O₂ used was carefully considered.

Which part of the work towards this paper proved to be most challenging?
The most challenging part of this paper was combining the uranium dissolution data and H₂O₂ decomposition rates. However, we were able to produce a logical pathway for U₃O₈ dissolution by H₂O₂ in bicarbonate solution which described all of the observed experimental data.

What aspect of your work are you most excited about at the moment?
We have successfully investigated the dissolution of uranium oxide into solution with H₂O₂ and bicarbonate in anoxic conditions, and have determined the effect of groundwater chemistry and uranium oxide form on the dissolution rate of uranium. Dissolution is an interfacial process at the solid/liquid boundary, yet we do not currently know the exact nature of the surface oxide during the dissolution reaction. This provides an exciting challenge for future studies to characterize the surface in-situ during dissolution to further understand the observed dissolution behaviour of uranium.

What is the next step? What work is planned?
The next step in this research project is the in-situ characterisation of the surface of simulated waste during dissolution reactions using spectroscopic techniques. In real-time we plan to observe the evolution of the surface chemistry as dissolution proceeds, and use this information to provide a deeper understanding of the observed uranium release rates.

The kinetics and mechanism of H₂O₂ decomposition at the U₃O₈ surface in bicarbonate solution
John McGrady, Yuta Kumagai, Masayuki Watanabe, Akira Kirishima, Daisuke Akiyama, Akira Kitamura and Shingo Kimuro
RSC Adv., 2021,11, 28940-28948

DOI: 10.1039/D1RA05580A, Paper

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We are very pleased to introduce Sergiusz Luliński, corresponding author of the paper ‘Development of structurally extended benzosiloxaboroles – synthesis and in vitro biological evaluation‘. His article has been very well received and handpicked by our reviewers and handling editors as one of our HOT articles. Sergiusz told us more about the work that went into this article and what he hopes to achieve in the future. You can find out more about the author and his article below and find more HOT articles in our online collection.

Meet the author

Prof. Sergiusz Luliński obtained the PhD degree in chemistry from the Warsaw University of Tech-nology in 2001. Since the beginning of his science career, his research interest has concentrated on main group organometallic chemistry. Currently, his work is focused on the chemistry of novel bio-active boracyclic compounds for applications in medicinal chemistry. He is also interested in the design of various organoboron compounds and their use as porous or luminescent materials. He has published 70 research papers in respected chemistry journals.

The Luliński research group

Could you briefly explain the focus of your article to the non-specialist (in one or two sentences only) and why it is of current interest?
Antimicrobial resistance (AMR) will become the most significant threat that humanity has to face in the coming decades. In our work, we explore a new class of boraheterocycles termed benzosiloxaboroles. They exhibit a large variety of biological activities, which can be exploited in future.

How big an impact could your results potentially have?
This work reports a new family of structurally expanded benzosiloxaboroles with a particular focus on deriva-tives with pendant arylsulfonate groups, which showed the most promising antibacterial activity, especially to-wards various strains of Staphylococcus aureus. In a general sense, our long-term project indicates that ben-zosiloxaboroles are promising antimicrobial agents as well as β-lactams inhibitors.

Could you explain the motivation behind this study?
Clinical strains of methicillin-resistant S. aureus have been a severe problem in hospitals and open treatment for many years. They are resistant to almost all β-lactams and often resistant to other classes of antibiotics. There-fore, it is necessary to search for novel potent antibacterials, preferably featuring a new mechanism of action.

In your opinion, what are the key design considerations for your study?
The key design considerations include the improvement of antibacterial potency of benzosiloxaboroles while simultaneously retaining their low cytotoxicity. In addition, we aim at development of effective methods for preparation of a library benzosiloxaboroles with diverse substitution pattern.

Which part of the work towards this paper proved to be most challenging?
The most tricky part of the project was the optimization of synthetic procedures including preparation of the key ionic intermediate as well as subsequent derivatizations with benzoyl and benzenesulfonyl chlorides as electro-philic partners.

What aspect of your work are you most excited about at the moment?
In our long-term work, we investigate the influence of the substitution of benzosiloxaboroles on biological activi-ty and physicochemical properties. It is exciting that benzenesulfonyl derivatives show such a high activity against S. aureus MRSA strains and enterococci which constitute a serious problem in medicine.

What is the next step? What work is planned?
We will continue the work on organoboron antimicrobial agents. Specifically, we would like to establish the correlation between structure and activity of substituted benzosiloxaboroles.

Development of structurally extended benzosiloxaboroles – synthesis and in vitro biological evaluation
P. Pacholak, J. Krajewska, P. Wińska, J. Dunikowska, U. Gogowska, J. Mierzejewska, K. Durka, K. Woźniak, A. E. Laudy and S. Luliński
RSC Adv., 2021,11, 25104-25121

DOI: 10.1039/D1RA04127D, Paper

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Keep up to date with our latest HOT articles, Reviews, Collections & more by following us on Twitter. You can also keep informed by signing up to our E-Alerts.

We are very pleased to introduce Magne Olav Sydnes, corresponding author of the paper ‘Photodegradable antimicrobial agents − synthesis, photodegradation, and biological evaluation‘. His article has been very well received and handpicked by our reviewers and handling editors as one of our HOT articles. Magne told us more about the work that went into this article and what he hopes to achieve in the future. You can find out more about the author and his article below and find more HOT articles in our online collection.

Meet the author

Sydnes obtained his PhD degree in 2004 from Australian National University under the guidance of Professor Banwell. He then worked as a postdoctoral fellow both in Australia and Japan, including two years as a JSPS postdoctoral fellow in Professor Isobe’s group at Nagoya University. In 2009 he joined International Research Institute of Stavanger, Norway, as a researcher. Since December 2011 he has been at University of Stavanger. Research interests include natural product synthesis, medicinal chemistry, catalysis, chemical biology, analytical chemistry, and environmental chemistry.

Could you briefly explain the focus of your article to the non-specialist (in one or two sentences only) and why it is of current interest?
The focus of the article is to make compounds that have antimicrobial activity that can decompose under light. The long term aim of our work is to make antibiotics that can decompose in the environment after they have done their work in the patient (human or animal).

How big an impact could your results potentially have?
Antimicrobial resistance is a big and growing problem. We see this as a potential solution to this problem (one of several). With an antibiotic that decomposes after use it will not be laying around in the environment for long enough to make it possible for microorganisms to generate resistance towards it.

Could you explain the motivation behind this study?
The motivation behind this study was to establish a strategy that makes it possible to decompose the active compound into inactive fragments.

In your opinion, what are the key design considerations for your study?
Two key design concepts: 1) a new scaffold that has not been used in antibiotics previously; and 2) having a system that can decompose at a pH similar to the pH of natural water. One of our compounds decomposes very efficiently at pH 8 and the pH of sea water is 7.5-8.4.

Which part of the work towards this paper proved to be most challenging?
The method for how to make our compounds decompose under light we established quite early in the project. What was more troublesome was to make compounds that actually had biological activity.

What aspect of your work are you most excited about at the moment?
I am excited about all the possibilities that this chemistry opens. Not just for antibiotics but for pharmaceuticals in general. We do see an increasing concentration of a range of pharmaceuticals in the environment (including antibiotics). This chemistry opens the possibility to increase their decomposition after passing through the patient’s body.

What is the next step? What work is planned?
We plan to use the results in order to make more active compounds and also make compounds that has activity towards Gram-negative bacteria.

Photodegradable antimicrobial agents − synthesis, photodegradation, and biological evaluation
Vebjørn Eikemo, Leiv K. Sydnes and Magne O. Sydnes
RSC Adv., 2021,11, 32339-32345

DOI: 10.1039/D1RA06324C, Paper

Submit to RSC Advances today! Check out our author guidelines for information on our article types or find out more about the advantages of publishing in a Royal Society of Chemistry journal.

Keep up to date with our latest HOT articles, Reviews, Collections & more by following us on Twitter. You can also keep informed by signing up to our E-Alerts.