Environmental Nanotechnology Group

One of the biggest long-term challenge humanity faces is conjugating social, economic and technological advancements with stewardship of the environment. Our group is working to address this challenge through scientific innovation, in particular through the concept of environmental nanotechnology, where material design at the nanoscale leads to processes that require fewer resources, produce less waste and consume less energy.

Our focus is on three distinct areas: Reducing the cost and energy consumption of water treatment and purification; the safe manufacturing of nanomaterials at a large scale; and the development of environmentally sustainable industrial processes. All these technological developments are underpinned by fundamental research on the effect of nanometre scale confinement on materials’ properties, design and manufacturing.

keywords: membranes; nanomaterials; environmental nanotechnology; water treatment; process intensification

Current projects:

FoAMM - EPSRC Established Career Fellowship in Water Engineering

The accumulation, in the environment and in human food supply chain, of organic micropollutants, highly toxic substances such as drugs, hormones or endocrine disruptors found at very low concentrations in water, represents today one of the biggest challenges to public health and the environment in the UK and other developed countries. As a large number of compounds, including common anti-inflammatories, antibiotics, hormones, pesticides and and herbicides, is added to the priority substances watch list for future regulation, there is an urgent need for novel technologies capable of degrading micropollutants safely and without generating significant increases in carbon emissions of the water industry, already accounting for about 5% of UK emissions.

Legacy technology comprising the majority of water treatment plants in the UK and other developed countries cannot remove micropollutants, requiring an additional treatment step to be added to the water treatment train. Alternative technologies currently being tested in the UK and abroad all have limitations, in terms of high energy costs or high capital costs or production of toxic by-products, which require further removal. 

My vision as an EPSRC Established Career Fellow in Water Engineering is to safely degrade micropollutants without significantly increasing carbon emissions or producing toxic by-products. I will achieve this by creating novel photocatalytic nanoporous anodic metal foams, combining the high surface area of slurries and the stability of immobilised systems requiring no downstream removal.

SynFabFun

Membranes offer exciting opportunities for more efficient, lower energy, more sustainable separations and even entirely new process options - and so are a valuable tool in an energy constrained world. However, high performance polymeric, inorganic and ceramic membranes all suffer from problems with decay in performance over time, through either membrane ageing (membrane material relaxation) and/or fouling (foreign material build-up in and/or on the membrane), and this seriously limits their impact.

Our vision is to create membranes which do not suffer from ageing or fouling, and for which separation functionality is therefore maintained over time. We will achieve this through a combination of the synthesis of new membrane materials and fabrication of novel membrane composites (polymeric, ceramic and hybrids), supported by new characterisation techniques. 
Our ambition is to change the way the global membrane community perceives performance. Through the demonstration of membranes with immortal performance, we seek to shift attention away from a race to achieve ever higher initial permeability, to creation of membranes with long-term stable performance which are successful in industrial application.

This is a 5-year EPSRC-funded Programme grant in collaboration with the Universities of Newcastle, Manchester and Edinburgh and Imperial College London.

At Bath, we lead research on the developed of 1D and 2D hybrid membranes for liquid separations and on the use of 3D printing to fabricate low-fouling membranes.

BIOBEADS

In BIOBEADS we propose to develop, in combination, new manufacturing routes to new products. Manufacturing will be based on a low-energy process that can be readily scaled up, or down, and the products will be biodegradable microbeads, microscapsules and microsponges, which share the performance characteristics of existing plastic microsphere products, but which will leave no lasting environmental trace. Using bio-based materials such as cellulose (from plants) and chitin (from crab or prawn shells), we will use continuous manufacturing methods to generate microspheres, hollow capsules and porous particles to replace the plastic microbeads currently in use in many applications. 

Cellulose and chitin are biodegradable and also part of the diet of many marine organisms, meaning they have straightforward natural breakdown routes and will not accumulate in the environment. BIOBEADS will be produced using membrane emulsification techniques. 

The project builds on our joint expertise in membrane emulsification for continuous production of tunable droplet sizes, dissolution of cellulose and chitin in green solvents and in characterization of nanoscale and microscale structures to study all aspects of particle formation from precursors, through formation processes, to degradation routes. Yhe primary focus will be spheres and capsules, for use in cosmetics and personal care formulations, but, by understanding the processes and mechanisms of formation of these spheres, we aim to be able to tailor particle properties to suit larger scale applications from paint stripping, to fillers in biodegradable plastics.

The BIOBEADS research team will work with industrial partners, including very large manufacturers of personal care products, to ensure that the research conducted can be taken up and used, so having a real, positive impact on the manufacturing of new, more sustainble products.

PLA RECYCLING

The disposal of plastic packaging represents a significant environmental problem; although recycling of plastics has increased in recent years, current recycling methods are mainly mechanical or chemical techniques that result in lower grade second life products and much material is also still disposed of to landfill. The introduction of plastics produced from biological sources such as plant derived sugars has potential to reduce reliance on fossil derived sources and decrease emissions of greenhouse gases associated with manufacture. Polylactide has emerged as one of the most promising biorenewable and biodegradable polymers which has uses in packaging, textile and biomedical applications. However, the lack of a reliable method for recycling polylactide could limit its widespread application and market growth.

We are addressing the above problems, together with the University of Birmingham, by developing a catalytic process for degradation/depolymerisation of PLA, integrated with a membrane separation to selectively isolate small molecule products within a specified molecular weight cut off range, as valuable products.

Sustainable Chemical Feedstocks

Our aim is to develop a sustainable, integrated platform for manufacture of industrial chemicals based on biological terpenoid feedstocks to complement carbohydrate, oil and lignin-based feedstocks that will be available to sustainable chemistry-using industries of the future. Our focus will include production of aromatics and amines which are particularly challenging targets from other biofeedstocks.

Terpenes are an abundant class of natural products based on the C5 isoprene unit. As hydrocarbons they are easily separated from aqueous environments and can be readily upgraded using existing petrochemical technologies. While terpenes have been used in limited quantities since antiquity (notably as flavours and fragrances) they have yet to be exploited systematically for the production of platform chemicals even though they represent a potentially vast resource: global biogenic production of terpenes is 10^9 t/yr.
We will develop new integrated technologies for terpene-based manufacturing, ultimately via microbial fermentation of waste cellulose, providing a competitive advantage for UK industries through new sustainable manufacturing processes, reduced feedstock costs, security of supply and reduced environmental impact. The UK will benefit further from export of new technologies and services and from development of new skills vital to future low carbon manufacturing.

1D and 2D membranes; photocatalytic membranes; CO2 conversion