The enhanced use of new generation TiO2–concrete systems for reducing hazardous gaseous compounds in the atmosphere across the whole of Europe is the main objective of the project..
The existing photocatalytic concrete does not perform well enough either under Northern skies, during winter time in Southern Europe or indoors. Commercially available photocatalytic cement and concrete usually contain ordinary TiO2. When used in outdoor applications for depollution purposes, only the small fraction of UV light in the sunlight radiation reaching the Earth surface, i.e. 0.5% in average of the total sunlight (measured at sea level in the temperate zone), is able to activate the photocatalyst. Indoor applications provide (with ordinary TiO2-based products already commercialised) extremely low efficiencies since UV radiation sources are not present and normal illumination cannot efficiently support photocatalytic reactions.
The proposed project includes the following objectives:
- Development and optimisation of TiO2 photocatalysts sensitive to visible light based on development of innovative crystal and band structure engineering and/or metal ion coupling; for more efficient catalytic removal of polluting emissions within the constraints of cost.
- Implementation of the developed photocatalysts in cementitious binders for concrete technology, establishing suitable methodologies to ensure adequate surface dispersion of the photocatalytic materials to obtain concrete surfaces with enhanced photocatalytic performances, high aesthetic and mechanical durability as well as improved resistance towards deterioration phenomena such as attrition, erosion and abrasion, therefore requiring less cleaning, lower replacement levels, and long term reduced resource use.
- Development and application of efficient and durable surface deposition in place of mixing photocatalyst and cement before concrete production, reducing the amount of active material in the bulk not reachable by pollutants and light and therefore reducing the overall level of active materials required. This will have the indirect effect of managing the costs of the new materials.
- Evaluation of the Life Cycle Assessment (LCA). LCA is an objective method to evaluate the burdens associated with all the elements including production and processing, by identifying and quantifying energy and material uses and releases, and to evaluate and implement opportunities to influence environmental improvements. In this project we will assess the life cycle of the product and process encompassing extracting and processing material; manufacturing, transporting and distribution; use, reuse and maintenance; recycling and final disposal.
- Assessment of catalytic lifetime. This objective aims to prove that the photocatalytic activities provided by the final materials are maintained over a period of time comparable with buildings and structures lifetime. This is considered an important issue to address because short catalytic lifetimes could be a barrier for builders and contractors in employing photocatalytic materials.
- Evaluation of the Life Cycle Cost (LCC). Like any other investments, the production should take into account the associated costs, with special attempts to minimise the environmental impact. In this project we will use LCC to yield the present value of the current and future expenditures for the production, use, reuse and maintenance of the selected materials and processes; recycling and final disposal. This will provide the data for companies to be able to present the financial implications of future savings due to additional investments made at present for enhancing performance of the process (e.g. energy efficiency or durability of materials) which can be assessed by end users for decision making.
- Increase the use of photocatalytic concrete technology across European and identify and secure new market sectors such as indoor applications, by engineering the better catalytic efficiency and thus reducing the levels of catalyst required to maintain, or reducing the cost or cost-benefit of the new material compared to existing photocatalytic concretes, removing technical barriers to take up in the otherwise receptive market. A strategy to reduce the cost-benefit ratio is: i) Reducing the total amount of photocatalyst due to higher performances; ii) Efficient and durable surface deposition rather than mixing photocatalyst and cement before concrete production that ends up in losing a lot of active material in the bulk not reachable by pollutants and light.
- Optimisation and engineering of photocatalytic concrete for urban paving, outdoor building facades solutions as well as air pollution mitigation motorway (noise, crash and protection) barriers optimised for degrading atmospheric hazardous compounds such as: NOx, SOx and VOCs in areas that do not lie within the sunlight favourable belt, Figure 1, and for improving the efficiency (and reducing the seasonal variation in performance) of pollution mitigation in regions of favourable sunlight.
- Engineering of photocatalytic concrete for indoor applications able to promote air cleaning properties by exploiting ordinary indoor lighting to degrade hazardous volatile compounds such as: methane, formaldehyde, short chain alcohols as well as microbial contaminants including mould and bacteria.
- Demonstration of outdoor/indoor applications and measurement and assessment of NOx, SOx and VOCs abatement compared to existing catalytic concretes in a range of relevant indoor and urban sites as well as assessment of aesthetic durability improvement in outdoor conditions.
- Development of ISO Standards for evaluation of photocatalytic activities towards NOx, SOx and VOCs abatement for different kinds of photocatalytic concretes (at the moment there is only one ISO standard relative to NOx abatement for photocatalytic paving blocks).
- Assessment of any potential health issues related to the use of nanoparticles in construction materials, in particular in indoor conditions. Although no particular danger is known by the use of nanostructured TiO2 in concrete structures, Light2CAT aims to confirm that these materials do not release nanoparticles that might compromise people health