Research course

Process optimisation of mediated electrochemical oxidation for the destruction of waste organics

Institution
University of Leeds · Faculty of Engineering
Qualifications
Integrated PhD

Entry requirements

You are required to have attained a 1st class or upper 2nd class undergraduate degree. To be eligible for a studentship, you must either be a U.K. citizen or a European Union national who has been resident in the U.K. for at least 3 years prior to starting the course. The NGN Centre welcomes applications from international students however this particular programme is funded by the Research Council which means we have limited funding opportunities for overseas students.

Months of entry

October, September

Course content

Process optimisation of mediated electrochemical oxidation for the destruction of waste organics

Project Overview

Mediated electrochemical oxidation, using Ag2+, has been developed and tested for a range of applications. In the 1990’s, the then AEA-T based at Dounreay, constructed and operated a pilot plant that proved the process was capable of destroying a range of organic compounds, such as tri-butyl phosphate from the fast reactor reprocessing plant. The plant operated at approximately 4kW power (on the electrochemical cell), which equated to batch size of approximately 10kg. In addition, to this application, MoD tested the process at a similar scale (at Porton Down) for the destruction of chemical weapons. Overseas, Los Alamos NL also proved the process for a similar range of applications.

Since then, the process has not seen any further development and was discounted by the MoD, who favoured a more standard pyrohydrolysis process for their chemical weapons destruction programme.

There are a number of reasons why the process may not been adopted:

1. Electrode design. AEA-T used platinum and platinised, which were not expensive, but did not have an optimised surface area. The LANL work was focussed on optimisation of the electrochemical system.

2. Control of Ag+/Ag2+ ratio in the anolyte. As the transport of Ag ions between the bulk liquor and the anode surface is the main mass transfer mechanism, the overall rate of the process is dependent on this.

3. Production of precipitates. This is an issue if there is any chlorinated hydrocarbons present in the organics waste stream.

4. Recovery of Ag+ from the liquid effluent. AEA-T proposed a process and tested to proof of concept and many alternative options exist.

In total these relate to a lack of efficiency compared to other processes and so leads to predicted higher costs. However, there are clear advantages of the MEO process and its effectiveness at destroying a wide range of organic compounds is of value to the UK nuclear industry.

This project will address some of the fundamental issues listed above and is aimed at proving a cell design that combines continuous operation with Ag recovery and recycle. The project will have a number of key tasks:

· Characterisation of the mass transfer kinetics within the MEO cell

· Definition and determination of a Ag recovery process that can be directly coupled to the MEO cell

· Definition and determination of the chemical engineering parameters for a continuous process: e.g. mass transfer rates, fluid dynamics mixing regimes.

The project will be mainly experimental, with a small MEO cell and equipment for Ag recovery. However, results will be used to construct a process model of the system.

The successful candidate will be working closely with industry. The project links into a Sellafield Ltd funded programme of work with NNL that investigates organics destruction and NNL’s programme on development of a process to produce 241Am for radioactive power units, funded by the ESA.

Applications are invited from candidates with a good first degree in a science or Engineering discipline, such as Chemical Engineering, Mechanical Engineering, Materials Science & Engineering, Chemistry and Physics. For more information, please contact the project supervisor: Prof. Bruce Hanson, email b.c.hanson@leeds.ac.uk

Next Generation Nuclear
The centre’s mission is to develop the next generation of research leaders to support the UK's present and future strategic nuclear programmes - cleaning up the nuclear legacy, building new nuclear power stations, and defence and security.

This exciting opportunity will involve close collaboration with key industrial stakeholders, including secondments into industrial nuclear research centres.

Further information
Indication of interest and initial enquiries should be made by sending a CV, a covering letter and university transcripts to Abby Ward preawa@leeds.ac.uk at the Institute of Particle Science & Engineering, School of Chemical and Process Engineering, University of Leeds.

Fees and funding

A full standard studentship consists of academic fees (£3,975 in Session 2014/15), together with a maintenance grant (£13,726 in Session 2014/15) paid at standard Research Council rates and a Research Training Support Grant.

Generally, UK students will be eligible for a full award and other European Union applicants will be eligible for an award paying academic fees and RTSG only, except in cases where residency in the UK has been established for more than 3 years prior to the start of the programme of study.

Places are available for students who have their own funding.

Qualification and course duration

Integrated PhD

full time
48 months

Course contact details

Name
Abby Ward
Email
A.M.E.Ward@leeds.ac.uk