Molecular Builders: Constructing Nanoporous Materials

Separations demand more than half of all the capital and operating costs associated with processing industries. This is because separation is often achieved by boiling liquids to make them turn into a gas. However, turning liquids into gases involves injecting a lot of energy, to overcome the attractive forces between the molecules of the liquid. One way of avoiding this large energy input is to carry out separations in the liquid phase via a membrane. This avoids the large energy injections of evaporation or distillation. Theoretical calculations show that the energy required for concentrating a mixture by membrane separation is less than 5% of the energy required to evaporate the liquid.

This project is to support a world leading research group research develop radical new ways of making membranes for separations. Now, we make them through mixing, pouring and smoothing out solutions of polymers and ceramics. This creates waste and is hard to control accurately. In the future, we want to make membranes by bit by bit through assembly of small units, and by creating well defined molecular structures where we know the positions of the molecules. We will do this by learning new techniques in materials engineering and chemistry, and putting them to work making membranes. To achieve this ambitious goal, we intend to learn the techniques we need from experts around the world. We will then bring them all together and focus on making membranes and filters for separations. Then, we will use these membranes in a wide range of applications that are currently not feasible with existing membranes.

For the platform grant renewal period, we will revolutionise the membrane fabrication process. We will seek to manufacture composite materials comprising a controlled porosity support, coated by a molecularly defined separating layer. This will require research into new ways to assemble porous polymer and inorganic support films, using functional printing, a rapidly developing technology for making 3D materials in a controlled way. We will then coat these controlled porosity support films with molecularly defined separating layers in which the molecular structure can be manipulated. Finally, we will develop imaging techniques to view the structures we have made at the nanometre scale. We will use the membranes to deal with separation problems that current membranes cannot reach, such as synthesis of pharmaceuticals in continuously operating reactors, production of DNA and RNA for therapeutic needs, and the recovery of water from salty and contaminated feeds generated in the oil and gas industry.

To succeed in this ambitious goal we will need to train our post-doctoral research team in a diverse range of techniques, most of which we do not employ currently. We will do this by working with other research teams around the world who are experts in the techniques we want to learn. Through a planned programme of research our post-doctoral team will gain valuable experience in areas almost completely different from those they have previously worked in, enabling them to establish and broaden their track record. Importantly, the platform grant will enable us to retain valuable knowledge and expertise in our group. This will provide the continuity necessary to maintain an internationally leading position, and also for the post-docs to build their expertise and multidisciplinary outlook through the planned acquisition of new skills. The synthesis of the new techniques, and their combination with our existing skills, will lead to world beating new science and engineering, and new products manufactured in the UK.

The economic benefits of the research proposed are the business around manufacturing and selling new materials that arise from the research, and the economic benefit of the applications of these materials.

The membranes research group at Imperial College has a strong demonstrated record in the commercialisation of membranes derived from its research. Evonik MET, based in West London, is the only dedicated manufacturing facility for organic solvent nanofiltration membranes in the world. The fundamental processes they used were developed at Imperial College with EPSRC research funding, much of it provided by the initial platform grant.

If the application for renewal is successful, it will generate a revolutionary range of new materials, with potential in separations, and other applications such as the preparation of composite materials. The most likely interest in these materials will come from companies who manufacture structured polymer and ceramic materials, including membrane manufacturers, and these companies may license the technology developed. Alternatively, there may be the opportunity for creation of new companies to develop and market these new materials, where this makes more economic sense, or where risk hinders larger companies from getting involved. In either case, economic benefits will derive, including investment in capital equipment and creation of skilled jobs, from the manufacture of these new materials.

A further economic impact will come through the application of these films to industry. We envisage that they will be used for filtration in organic solvents, and also in desalination and filtration of water. Membranes are generally one of the lowest energy forms of separating components of liquids, and so the end users will obtain economic benefits from energy savings and reduction in complexity of their processes. These end users are likely to be industrial companies operating in the full range of chemical sciences businesses, from oil and gas extraction and refining to the food, chemical and pharmaceutical industries. It is important that the materials we create can be manufactured, and we have deep experience with the scale up to commercial use of developmental materials. It is instructive to note that sales of membranes for desalination and nanofiltration are around £2 billion. If our printed membranes became the paradigm replacing the current support membranes used in RO composite membranes, the technology we propose to develop could be truly revolutionary.

These economic benefits have parallel social benefits. The manufacture of advanced membrane materials creates high level and knowledge intensive employment, and improves the national accounts through exports achieved. The application of the new materials in industry will reduce energy consumption, and so CO2 production; and the purification of water is a key societal need.