Satellite T-RHEXI 29th RAU

Short CV: Thomas Connolley is the Principal Beamline Scientist for the I12 Joint Engineering, Environmental & Processing beamline at Diamond Light Source. He has a degree in Metallurgy and the Science of Materials from the University of Oxford, a PhD in Materials Engineering from the University of Southampton, and is a Chartered Engineer and Member of the Institute of Materials, Minerals & Mining. He joined Diamond as a Beamline Scientist in 2006, with a major role in the design, construction and commissioning of the I12 JEEP beamline. He has previously worked for British Aerospace in the UK, Materials Performance Technologies in New Zealand and The National Centre for Biomedical Engineering & Science in Ireland. His current research interests are in High Speed X-ray imaging, Time-resolved Diffraction and Stroboscopic X-ray Diffraction. A collaboration with the University of Hull, UK, is using X-ray imaging and tomography to study the influence of alternating magnetic fields on the solidification of aluminium alloys. The stroboscopic diffraction technique is being used to study dynamic strains in rotating machinery, in a collaboration with the Universities of Bristol and Sheffield and the Science and Technologies Facilities Council (STFC). Dr. Connolley is an author on 78 publications, with over 1000 citations.

Title: High Energy Imaging and Diffraction at Beamline I12: 10 Years of Experience and Lessons Learned

Abstract: I12 is the Joint Engineering, Environmental and Processing (JEEP) beamline, constructed during Phase II of the Diamond Light Source. I12 is located on a short (5 m) straight section of the Diamond storage ring and uses a 4.2 T superconducting wiggler to provide polychromatic and monochromatic X-rays in the energy range 50–150 keV. The beam energy enables good penetration through large or dense samples, combined with a large beam size (1 mrad horizontally × 0.3 mrad vertically). The beam characteristics permit the study of materials and processes inside environmental chambers and on sample sizes that are more representative of bulk materials. X-ray techniques available are radiography, tomography, energy-dispersive diffraction and monochromatic 2D diffraction/scattering.  Since commencing operations in November 2009, I12 has established a broad user community in materials science and processing, chemical processing, biomedical engineering, civil engineering, environmental science, palaeontology and physics. The majority of experiments are time resolved, in-situ studies, often involving processing equipment brought by users.

Title: 4D study of groundwater remediation using nano and chemical based technologies

Abstract:

Authors: Tannaz Pak¹, Luiz Fernando de Lima Luz Jr², Tiziana Tosco³, Paola Rosa⁴, Gabriel Schubert⁴, Nathaly Lopes Archilha⁴

¹Teesside University, ²Federal University of Parana, ³Polytechnic University of Turin, ⁴Brazilian Synchrotron Light Laboratory (LNLS) – Brazilian Centre for Research in Energy and Materials (CNPEM)

Chlorinated solvent contaminants are among the most recalcitrant aquifer contaminants which can cause serious health problems (e.g. kidney and liver damage) and some are considered as carcinogenic. They are classified as DNAPLs, i.e. dense non-aqueous phase liquids. The scale of the problem posed by these contaminants is globally significant due to their wide industrial use since the beginning of 20^th century e.g. in metal processing plants. In Brazil this is a major problem especially in the state of Sao Paulo. Removal of chlorinated contaminants from the host aquifers can be done by (i) pumping for ex-situ treatment, or (ii) injecting reagents for in-situ degradation into less harmful substances.  The latter has received more attention recently as it offers a non-invasive means for contamination elimination.

Nanoremediation is an emerging technology with great potential for in-situ degradation of chlorinated contaminants and many other metal contaminants (e.g. Cr, As, etc.). The technology injects Fe⁰ nanoparticle in form of aqueous suspensions into contaminant bearing sediments². These nanoparticles are highly reactive and excellent electron donors (Fe⁰ à Fe²⁺+ 2e¯). Chlorinated solvents can readily accept those electrons and release their chlorine atoms in form of ions. Example reaction: (C₂H₂Cl₂+ Fe⁰ + 2H⁺àC₂H₄ + 2Cl¯+ Fe²⁺). While nanoremediation concept is proven to be successful at laboratory, pilot, and field scales, the existing practice is far from optimised.

In-situ chemical oxidation (ISCO) using KMnO₄ for degradation of trichloroethylene (TCE) is another useful technology. However, the chemical reaction between KMnO₄ and TCE (C₂HCl₃+2KMnO₄⇒2CO₂+H++2K++2MnO₂+3Cl-) results in precipitation of a solid phase (MnO₂) which has shown to reduce the permeability of the host sediment and eventually encapsulate the TCE droplets, hence limiting sustainable delivery of the oxidising agent to the contaminated areas of the aquifer.

In this work we study the two above mentioned remediation technologies by performing 4D (time-resolved, 3D) experiments comprising flow injections (in sand columns) and simultaneous 3D imaging using X-ray computed micro-tomography (micro-CT) technique.  The study, conducted at the Brazilian synchrotron, for the first time, has captured the evolution of TCE phase structure/distribution, in 3D, during the nanoremediation/ISCO processes. Our data show that the gas phase released during the nanoremediation reaction remobilises the trapped TCE phase, facilitating its complete removal in subsequent soil flushing processes. Our findings provide new insights into the pore-scale physics of the nanoremediation and ISCO process and contribute to optimisation of this process.