PHOCSCLEEN · PHOtoCathalytic Systems for CLean Energy and Environment Applications

PHOtoCathalytic Systems for CLean Energy and Environment Applications

PHOCSCLEEN project aim was to gather competences and knowledge across the Atlantic Ocean to develop new and more performing materials and composite systems for photocatalysis of pollutants and water splitting applications. The project smoothly run along the route defined in the application, achieving all targets and eventually going further. One of workpackages, namely WP2, focused on photocatalytic materials with the targets: (i) optimize existing materials, (ii) find new cheaper and/or more reliable routes to produce such materials, and (iii) produce and investigate new materials for the targeted applications. These targets were reached as in the framework of the project it was possible to achieve the - preparation of metal oxide nanoparticles able to exploit the visible part of the solar spectrum but at the same time leading to faster degradation of dyes than commercial TiO2 nanoparticles under UV illumination - preparation of metal oxides that can perform both oxidation and reduction of water molecules with a simpler procedure than reported in previous literature - preparation of metal oxides having high efficiency in water splitting under UV and solar light A further target, encompassed in WP3, was to produce composites by dispersing photocatalytic materials in powder form in a host porous polymer in order to achieve immobilization and shape tailoring. This target had to be revisited because of induced degradation of host polymer (which might become an advantage for polluting polymer degradation but such a scope was beyond the Phocscleen targets). However successful research activity was carried out in this respect too as Phocscleen activity led to the following outcomes: - growth of photocathalytic materials on metal grids. This achievement is relevant for application as it allows at the same time (i) immobilization of the active material, (ii) reduction of the shadowing effects compared to monolythic substrates, and (iii) reduction of hydraulic losses - growth of photocatalytic materials inside water filters with a marginal loss in efficiency, mainly related to optical shadowing effects. As water filters are common in water treatment plants this solution will require minimal modification of existing plants in order to achieve targeted antipollution effects. - realization of single particle heterojunction exploiting (i) segregation in the case of bismuth ferrite / bismuth oxide and (ii) selection of appropriate growth conditions for the case of biphasic bismuth oxide. Single particle heterojunctions allows a very efficient separation of photoinduced electron-hole pairs with reduced recombination rate increasing the effectiveness of the process. Two were the application focused workpackages, namely WP4 (focusing on photocatalytic treatments) and WP5 (related to water splitting). Phocscleen team has reached interesting results in both respects. As per WP4 related issues the highlights are: - production and optimization of bismuth ferrite nanostructures having high efficiency in dye and phenoles degradation due to their ability to exploit the visible region of the solar spectrum - identification of the cooperative effect of bismuth-based photocatalytic materials on dye mixtures that leads to faster discoloration of the mixtures with respect to single dye cases - production of metastable phases of bismuth oxide having higher efficiency than titania nanoparticles benchmark under UV light It has to be noted that the water treatment capabilities of some of the developed materials goes beyond their photocatalytic properties as they have proved themselves interesting also for their arsenic and heavy metal sequestration abilities. As per water splitting a number of interesting results have been obtained. Among them the most interesting is the development of a low cost reliable and scalable procedure, including growth process and post treatment, that allows the production of undoped bismuth vanadate having benchmark-like characteristics. The results outlined above have been duly disseminated on peer reviewed international journal (12 papers published, 5 due for submission) and talks delivered at international conferences. The results obtained have potentially a wide impact on the treatment of water for a number of reasons: 1) the ability to exploit sunlight as an activator of photocatalytic processes will allow to reduce the energy consumption and/or increases the efficiency of treatment plants 2) the availability of coated metal grids will allow to increase the photocatalytic active area within a given tank volume 3) the availability of photocatalytic materials filled water filters will allow to convert existing polluted water reservoir to photocatalytic water treatment systems by substituting standard filters with this new type of filter with minimal impact In a perspective that goes beyond European horizon Phocscleen results might be of particular interest for the Indian subcontinent. It is widely known that (i) textile industries are widespread in the northern part of the subcontinent, and that (ii) native water is quite rich in arsenic. Hence a bivalent system able to remove both dyes and arsenic from waste water will lead to water having more potability than the natural water entering the textile industry plants. And this will happen at limited additional energy costs as the energy source will be sunlight. As a consequence of what discussed above the results of Phocscleen will be of interest to policy makers as well as of companies involved in textile industries. More info on the project, its members and it outcome, as well as contact information can be found on the website www.polito.it/phocscleen

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз