Project Title: A green approach in the frame of circular economy: robocasted photocatalysts for wastewater treatment and use of reclaimed water in agriculture

Acronym: WaterGreenTreat

Funding Entity: Water4All – Agencia Estatal de Investigación (AEI) (PCI2024-153414)

Participating Entities:  University of Extremadura (Spain), National Institute of Materials Physics (Romania), Universidad de Bucharest (Romania), University of Agriculture and Life Sciences (Hungary), Centre National De La Recherche Scientifique CNRS GEPEA UMR6144 (France)

Duration: 01/04/2024 – 31/03/2027

Budget: 898596 €  (UEX: 181250 €)

Principal Investigator (PI): Antonia Pajares

Number of researchers: 3 (UEX)

Abstract:

Usually, for the purification of industrial wastewater, physico-chemical methods of removing harmful substances are used simultaneously or incombination with biological treatment. Nanomaterials containing nanostructures such as CuO and ZnO with different forms, shapes and sizes have been found to be effective in removing environmental pollutants from water through photocatalytic activities. However, an additional post-separation step such as precipitation, filtration, or centrifugation is required to remove them. This separation process significantly increases the total cost of water treatment. Hence, there is a major interest in developing new technologies to obtain efficient photocatalysts in large amounts at a low-price.

To accomplish those requirements, WaterGreenTreat project aims to develop photocatalysts based on metal oxides (ZnO/CuO) composites by additive manufacturing. In particular, macroporous structures with controlled microstructure and pore architecture will be fabricated by robocasting from commercial CuO and ZnO nanoparticles and also obtained by green synthesis. The printed structures will be consolidated by fast sintering process to prevent, as much as possible, grain growth and hence preserving their photocatalytic activity. In this way, environmental impact associated to the manufacturing of these 3D metal oxide photocatalysts will be minimized by reducing energy consumption (fast sintering techniques require only 20-30% of the power used in conventional fabrication routes) and minimizing waste through the additive manufacturing process. The novel robocast photocatalysts are expected to be eco-friendly and to have good physical stability, photocatalytic activity and antioxidant properties. Besides, the use of these 3D printed photocatalysts based on metal oxide nanoparticles can avoid contamination of the treated water with metal ions that can be generated from the metal oxide when they are used in powder form.

The developed 3D structures can be used to remove contaminants such as drugs (antibiotics, ibuprofen) or dyes (methylene blue, rhodamine B) from the wastewater generated by the pharmaceutical or textile industries. These industries require huge amounts of water, causing environmental pollution. Thus, this original approach for the development of new materials as photocatalysts based on metal oxide composites can be considered a significant step in wastewater treatment as it will increase the amount of reclaimed water and facilitate the reuse of reclaimed water in other fields such agriculture, and hence the effects of extreme hydroclimatic events (high temperatures and droughts) on plants can be mitigated.