Biomass-based Porous Functional Materials for Photothermal Decontamination of Water

Water is extremely important for all living things. But global economic development, climate change, and population growth have put water resources under stress. Particularly, freshwater production is decreasing continuously. In the coming years, billions of people will be under water stress conditions. So, serious actions need to be taken. Interfacial solar steam generation is a promising and sustainable approach, which uses solar light as a renewable energy source with low environmental impact, to tackle freshwater scarcity. However, low solar absorbance and high heat losses cause poor solar-to-vapour conversion efficiency. In recent years, several photothermal materials have been developed to be used in solar evaporator devices, yet many problems need to be resolved. For instance, photothermal materials should be low-priced, eco-friendly, stable in harsh conditions, and easy to fabricate. Considering these factors, we have developed different sustainable photothermal functional materials using bone and vegetable waste, with highly porous structure, low weight, enhanced wettability, prolonged stability in water, high optical absorbance, low thermal conductivity necessary for that localization, and adequate solar-to-vapour conversion efficiency. The solar evaporation rate achieved is >1.1 kg m-2 h-1 with a solar-to-vapour conversion efficiency of >80% under 1 Sun irradiation. The prepared biomass-based materials can successfully desalinate artificial seawater, and decontaminate synthetic wastewater, (e.g. water containing dye molecules and hazard metal ions) with an efficiency of >98%. Most importantly the developed materials present salt anti-fouling ability and anti-bio-fouling properties. Thus, the multifunctional highly porous biocomposite photothermal materials prepared in this thesis are a cost-effective promising solution for prolonged wastewater decontamination processes. Last but not least, in this thesis, we also propose effective solutions to valorize food waste offering solutions to two major issues of modern society: water shortage and waste management.