PhD

Journal Publications

Throughout my time studying for my PhD, I have published several peer-reviewed papers in respected journals.

Awards

Recognition for my work has also been noted through a series of awards within the university and at international conferences.

1^st place poster at Technical Plasma Workshop 2015

1^st place presentation at the Midlands Energy Consortium 2015

Heat winner at EngineeringYES Solihull 2016

Runner Up at EngineeringYES Grand final 2016

1^st place poster at Technical Plasma Workshop 2016

1^st place poster at IOA3 2016

3^rd place photo at Loughborough University research conference 2016

3^rd place photo at EPSRC photo competition 2016

Nominee Loughborough Doctoral College Student of the Year 2018

Grants & Patents

I have been part of the team behind several separate grant applications for the sum value of £100 k to commercialise different aspects of my research. To the protect the IP two patents are currently in preparation with a filing date due this autumn.

Thesis Executive summary

A full copy of my thesis can be shared on request, the executive summary is as follows.

Atmospheric pressure plasmas have been applied to a multitude of liquid-based applications such as wound healing and small scale chemical processing. Under these conditions, a plasma jet placed above the liquid is favoured, that is typically supplied with argon or helium. For large scale processes such as wastewater or biomass treatment, localised plasma jets become uneconomical and inefficient. In the work presented in this thesis, a novel microbubble-enhanced DBD plasma reactor is presented which allows efficient transport of highly reactive species from the plasma to the liquid medium. This novel design allows the discharge to be formed in the immediate vicinity of the gas-liquid interface enabling effective mass transfer of the short-lived species.

The reactor was characterised in the first instance to evaluate and optimize its performance by varying all the input parameters. These studies include understanding the effect of the bubble size, input gas composition and input power supply. The reactive species generated in the gas phase were measured using absorption spectroscopy, and the liquid phase concentrations of the reactive species were measured using a variety of chemical probes. By modelling the reactor, a more in-depth analysis could be facilitated as tracking of short lives species over a high time resolution is then feasible. This lead to improvements in efficiency by selecting power supply operating conditions dependant of the plasma chemistry required. As one of the key reactive species is ozone being able to quantify this concentration in the liquid phase with both precision and accuracy is essential. This led to the development of a selective chemical probe to carry out such a task and was compared against pre excising measurement techniques.

The reactor was then applied to two applications, the pretreatment of biomass and the treatment of final wastewater effluent. Treatment of biomass is often required to break apart the structure to ease the conversion of the biomass feedstock to a fuel, usually facilitated by enzymes or bacteria. By treating a solution of biomass with the reactor, the oxidative species transferred to the solution were found to attack the structure increasing the yield of both methane and ethanol dependant upon the process post-treatment. Limitations of the process where also identified with future improvements suggested for such a technique.

When treating a solution contaminated with E. coli the oxidative species where seen to effectively inactive the bacteria within the solution. Importantly however a limitation of the system used, and others based on reactive oxygen species (ROS) to inactive bacteria was identified. Presence of organics such as humic acid significantly reduces the inactivation rate as they offer a competing reaction of ROS with the bacterium.