From organic wastes to the production of nanomaterials for energy and environment

The organic waste represents an energetic resource and it can be always burned in order to get rid of it. Nevertheless, it possesses as well different properties, which can be exploited to benefit our environment. In this work, the organic wastes are used as ecofriendly resource for the production of nanomaterials for environmental protection or renewable energies. Two types of organic wastes have been selected, bio-based soluble compounds extracted from green wastes (BBC-GC) and hair wastes (HW). BBC-GC are high molecular weight supramolecular aggregates with strong microstructural templating ability and photochemical properties; HW are very interesting raw materials due to the fiber structure of keratin, the main component of the hair. The waste-derived nanomaterials have been prepared by two different methodologies: grafting of BBC-GC onto different mesoporous silica supports; solution combustion synthesis by using the HW or the BBC-GC as combustion fuel, complexing agent and microstructural template. Results show that the waste-derived nanomaterials have peculiar properties and can be successfully used as photosensitizers for wastewater treatment or as cathode materials for intermediate temperature solid oxide fuel cells. The cycle is thus closed: from the environment to the wastes, from the wastes to the environment.