Catalysis at the Water and Energy Nexus

Led byĀ Professor Christopher Hardacre
This theme includes the following projects:
  • Treatment of High Ionic Strength Waste Water;
  • Catalytic treatment to reduce biofouling of membranes;
  • Energy-efficient catalytic advanced oxidation processes for water and waste water treatment;
  • Catalytic transformations in and with water;
  • Energy and fuels from waste water;
  • Life cycle sustainability assessment;
  • Modelling.

Severe water shortages in parts of the world have been increasing over the last 20 years due to the increased usage in agriculture, changes in the climate, increases in the global population and utilisation in industrial processes and it is estimated that over 660m people do not have access to clean water. The issue of water supply is now as much of a challenge of developing more sustainable energy supplies and these are intimately linked. Catalysis is a key underpinning technology to address the issues of clean water, more efficient utilisation/valorisation of water systems and the use of water as a reaction medium or reagent. It is recognised that there is a clear priority across government and the Research Councils in the area of water. The Hub model provides a unique opportunity to tackle this wide area through experimentation coupled with the incorporation of life cycle analysis and simulation science. The proposed work programme brings together aspects of the energy, environment and biocatalysis themes of the Hub in phase 1 into a coherent new theme which addresses the use of catalysis in the usage, valorisation and treatment of water in the chemical and energy industries. In particular it aims to provide catalytic solutions to enable energy efficient catalytic processes using water as a reagent or solvent for fine chemical production, utilisation of waste water as a resource for chemicals and fuels as an alternative to waste water treatment, increasing the efficiency of waste water treatment for produced waters from across the energy and chemical industries and, importantly, life cycle and sustainability assessment of these processes. This then will address some of the disadvantages of the current approaches, including the need to use visible light, as well as employ the technology for less traditional applications.

WP1: Treatment of High Ionic Strength Waste Water (Lead: Hardacre, Manchester)

There is increasingly an issue with the large amounts of contaminated produced waters which result from oil and gas the production processes particularly with the expected increase in the exploitation of shale gas worldwide. One of the major challenges in the treatment of this waste water is the fact it contains a wide range of impurities and is often highly saline. This work package aims to explore chemo and bio-catalytic approaches to the treatment and valorisation of the produced waters and the engineering challenges associated with these approaches.

WP2: Catalytic treatment to reduce biofouling of membranes (Lead: Plucinski, Bath)

Membranes are becoming a major route for the removal water and/or clean up polluted water in the water and chemical industries and has a global market of > $400m in 2014 [1]. However, ā€œmembrane fouling is still the biggest challenge and the major obstacle for the widespread implementation of membrane processesā€ [2]). The fouling results in reduced efficiency of the membrane process and the need for increased energy input. This workpackage aims to address the removal of the foulants using catalytic processes.

WP3: Energy-efficient catalytic advanced oxidation processes for water and wastewater treatment (Lead: Hutchings (Cardiff))

Access to clean water is a crucial requirement for a modern society; however, clean water is a diminishing resource. Currently industrial wastewater can cause severe environmental problems owing to the dissolved toxic and non-biodegradable organic compounds and these can cause various health and environmental problems and hence effective economical techniques are necessary to mitigate the effects of these pollutants. Current methods either rely on concentrating and separation but at present catalysis does not play a role in this important area. Modern catalysis can provide a solution to water purification and this will be explored as the main topic of this WP.

WP4: Catalytic transformations in and with water (Lead: Marr (QUB))

The transition to more sustainable energy and chemicals industries will require a wide expanse of technologies and in particular, a large variety of catalytic methods. One of the major challenges is the utilisation of biomass as a chemical source. The conversion of biomass into liquid fuels and chemicals is difficult, as these feeds tend to be aqueous, impure and dilute. For this reason catalytic processes that occur in water are essential. During the current decade whole cell biocatalysis has been shown to provide efficient catalytic routes to chemical targets from impure biomass. However, two major challenges remain, firstly natural whole cell catalysts operate in highly dilute aqueous media, and secondly a range of products are produced; this results in an impure dilute product and a difficult separation.

WP5: Energy and fuels from waste water (Lead: Ross (Leeds))

Anaerobic digestion of wastewater solids leaves behind stabilised sludge containing fibrous biomass, bacterial debris and inorganic material residue that is suitable for hydrothermal processing. Restrictions for the disposal of this material is stimulating research in alternative routes for valorisation to fuels and chemicals. Hydrothermal treatment involves the conversion of sludge in hot compressed liquid water and can produce either a solid hydrochar, a liquid biocrude or a syngas depending on conversion severity. Hydrothermal treatment of these biosolids in sub- and supercritical water (<500 Ā°C) has the potential advantage of reducing the process energy demands compared to drying and pelleting, while also offering an opportunity to recover nutrients salts and produce biofuels and platform chemicals. To realise this goal requires the development of catalytic processes and technology that can work at different levels of organic contamination spanning hydrothermal processing to microbial fuel cells.

WP6: Life cycle sustainability assessment (Lead: Azapagic (Manchester))

The overall aim of this research project is to develop a decision-support framework to aid sustainable design and selection of treatment methods being developed in the other research projects by coupling life cycle sustainability assessment with technology development.

WP7: Modelling (Lead: Catlow (UCL/Cardiff))

Modelling is now a generic set of methodologies that will contribute to the majority of the work-packages by providing a molecular level understanding of structure and mechanism in catalytic processes for which it is now an established tool. Our approach is to combine the full range of contemporary molecular modelling techniques including both force-field and electronic structure methods to obtain accurate descriptions of real catalytic systems. The approach and contribution of modelling will be illustrated by examples relating to the other work packages discussed above.

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