Hybrid plasma-catalytic oxidation of organic solvents from nuclear industry

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There is a significant amount of untreated radioactive waste containing organic species in storage both in the UK and around the world. The waste remains untreated due to there being no adequate systems in place that can treat the wide range of organic species incorporated.The aim of this project is to develop a non-thermal plasma process for the treatment of these low and intermediate level waste organics. Non-thermal plasma provides an attractive alternative to the conventional route (thermal combustion) for the indiscriminate decomposition and oxidation of organic oils and solvents at low temperatures. The fast attainment of steady-state and high reaction rate in plasma processing allows for a rapid start-up and shutdown of the process compared to other thermal treatment technologies, which significantly reduces the overall energy cost and offers a promising and flexible route for industrial applications. This PhD is also looking at the combination of plasma and solid-state catalysts, also known as hybrid plasma-catalysis, which has great potential to generate a synergistic effect, significantly enhancing the conversion of organic liquids, the selectivity of end-products, as well as the energy efficiency of the plasma process.Experimental tests will be carried out to understand the effect of a wide range of processing parameters (e.g. input power, frequency, flow rate, dilution gas, etc) and catalysts on the oxidation of organic solvents (e.g. a model organic compound and/or a mixture of organic compounds) and generated gas and liquid by-products. Plasma chemical kinetic modelling will be developed in combination with advanced plasma diagnostics (e.g. time and space-resolved optical emission spectroscopy) to understand the roles of different reactive species in the plasma oxidation process and the possible reaction pathways and mechanisms involved in the hybrid plasma-catalytic process. This project is highly interdisciplinary and will provide a unique chance to bring together expertise from plasma physics, plasma chemistry, catalysis, kinetic modelling and nuclear decommissioning to address a key challenge in nuclear industry. This work has been supported by the Centre for Innovative Nuclear Decommissioning (CINDe), which is led by the National Nuclear Laboratory, in partnership with Sellafield Ltd and a network of Universities that includes the University of Manchester, Lancaster University, the University of Liverpool and the University of Cumbria.