Peter W. Dunne

A novel terephthalate-based ionic liquid catalyst is promotes highly efficient neutral hydrolysis of PET without attendant catalyst inactivation or product contamination.

Materials science research has expanded significantly in recent years; a multidisciplinary field, home to an ever-growing number of chemists. However, our general chemistry degree courses have not changed to reflect the rise in interest in this topic. In this paper, we propose a laboratory experiment for the undergraduate chemistry practical course, which may serve as a hands-on introduction to this field. The experiment involves the synthesis and characterization of magnetic materials via commonly employed techniques in materials science. Students begin by producing three metal ferrite spinels using a sol-gel combustion synthesis. They must then characterize the differing magnetic properties across their three samples using a magnetic susceptibility balance. In the second part of the experiment, students must create a ferrofluid via coprecipitation, from which they may observe the phenomenon of "spiking" in response to an external magnet. Additional data such as X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images corresponding to these materials are also provided, and students are tasked with the interpretation of these data in their writeup report. Upon completion, students should gain a new-found understanding of materials science and its fundamental overlap with chemistry.

Solvothermal treatment of amorphous titania in trifluoroacetic acid modifies the surface and crystallises the anatase phase, yielding dispersible hybrid nanocrystals.

Here, we report the preparation, characterisation and testing of highly promising nanofiltration membranes produced from partially oxidised BN (BNOx) 2D nanosheets.

In recent years, nanotechnology-based approaches have resulted in the development of new alternative sustainable technologies for water purification. Two-dimensional (2D) nanomaterials are an emerging class of materials for nanofiltration membranes. In this work, we report the production, characterisation and testing of a promising nanofiltration membrane made from water-exfoliated boron nitride (BN) 2D nanosheets. The membranes have been tested for water purification and removal of typical water-soluble dyes such as methyl orange, methylene blue and Evans blue, with the water-exfoliated BN membranes achieving retention values close to 100%. In addition, we compared the performance of membranes made from water-exfoliated BN with those produced from BN using sonication-assisted liquid exfoliation in selected organic solvents such as 2-propanol and N-methyl-2-pyrrolidone. It was found that membranes from the water-exfoliated BN showed superior performance. We believe this research opens up a unique opportunity for the development of new high-performance environmentally friendly membranes for nanofiltration and new sustainable separation technologies.

Continuous-flow hydrothermal and solvothermal synthesis methods (CHS and CSS) have their origin in the early 1990s with the pioneering work of Prof. Adschiri exploiting the properties of supercritical water to achieve the generation of a range of binary metal oxide nanoparticles in a flow system. Since its inception, a great deal of work on CHS has focussed on overcoming the physical and engineering challenges it presents. Just as these engineering challenges were overcome, so were the new chemical obstacles raised by the technique surmounted. From its beginnings as a novel route to binary metal oxide nanocrystals, the CHS/CSS method now offers a clean and scalable synthetic process for the production of a vast array of (nano)materials, including more complex tertiary and ternary metal oxides, metal sulphides, metal phosphates, metals, layered double hydroxides, and even porous materials such as zeolites and metal organic frameworks. Here, we review the progress made in expanding the scope of the CHS method to these various classes of materials, with a focus on the chemical challenges, and opportunities, presented by continuous-flow hydrothermal and solvothermal techniques.

This chapter reviews the origins of continuous hydrothermal/solvothermal synthesis and their respective technical and engineering links back to batch synthesis. The mechanisms of formation via nucleation and growth stages are discussed and how these stages can be controlled through rapid mixing of a preheated fluid with a cold flow carrying an aqueous metal salt. The difficulties in moving from batch to continuous synthesis are also discussed, as well as how many researchers across the world have attempted to solve these issues using modelling and empirical measurements of the continuous mixing process. The modelling approaches include computational fluid dynamics and pseudo-fluid mixing, which uses surrogate fluids to represent the two fluids inside the high-temperature high-pressure vessel. Empirical measurements have either been via trial and error experiments using different reactor designs or with neutron beam experiments able to actually visualise the mixing in situ. These approaches have all contributed to the ‘rules’ around the design of continuous reactors for continuous flow synthesis. These ‘rules’ are discussed in detail. The road to scale up is also discussed in the chapter whereby bench scale developments have been commercialised via pilot scale systems on to full scale systems at 10–1000 tons per year. The benefits of the continuous process are also discussed in detail, along with sustainability assessments that show the process to have a relatively low impact on the environment.

The minerals studtite, [UO₂(η²-O₂)(H₂O)₂]·2H₂O, and metastudtite, [UO₂(η²-O₂)(H₂O)₂], are uranyl peroxide minerals that are major oxidative alteration phases of UO₂ under conditions of geological storage. The dehydration of studtite has been studied using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy. XPS of the U 4f region shows small but significant differences between studtite and metastudtite, with the 4f binding energy of studtite being the highest reported for a uranyl mineral studied by this technique. Further information about the changes in the electronic structure was elucidated using U M₄-edge high-energy resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy, which directly probes f orbital states. The transition from the 3d to 5fσ* orbital is sensitive to variations in the U═O_axial bond length and to changes in the bond covalency. We report evidence that the covalence in the uranyl fragment decreases upon dehydration. Photoluminescence spectroscopy at near-liquid helium temperatures reveals significant spectral differences between the two materials, correlating with the X-ray spectroscopy results. A theoretical investigation has been conducted on the structures of both studtite and metastudtite and benchmarked to the HR-XANES spectra. These illustrate the sensitivity of the 3d to 5f σ* transition toward U═O_axial bond variation. Small structural changes upon dehydration have been shown to have an important electronic effect on the uranyl fragment.