PhD defence of Lais Taguchi Possari

Upcycling Orange Waste into Porous Carriers for Organic Phase Change Materials

Lais Taguchi Possari carried out her doctoral research under the supervision of Tatiana Budtova, S&P team within a joint supervision with the Federal University of São Carlos (UFSCar), Brazil. Her defence takes place at the Department of Materials Engineering (DEMa), Federal University of São Carlos

Abstract of her research:
The goal of this project is to produce bio-based porous materials from “bulk” (i.e. with no chemical extraction processes) orange juice by-products and evaluate their performance as carriers for phase change materials (PCMs). Different types of residues were used, namely peels, bagasse, pulp and mixed biomass (total output: 56% peels, 28% bagasse and 16% pulp). PCMs are materials that have high latent heat and, thus, can store or release large amounts of thermal energy during phase transitions at approximately constant temperatures. Most PCMs work based on solid-liquid transitions, presenting leakage problems, which can be minimized by placing them in porous scaffolds. By-products from orange juice were selected to make these scaffolds. The “bulk” biomass was used to make suspensions (containing soluble and insoluble matters) via acid hydrolysis with citric acid. Because of the presence of insoluble matter, phase separation was a problem, and the kinetic stability of suspensions was studied as function of preparation parameters (use of biomass washed with water or unwashed, dry matter and citric acid concentrations). Materials were produced from the suspensions with different drying routes (supercritical drying, lyophilization and evaporation), non-solvent used on required steps prior to the supercritical drying (ethanol and acetone) and shapes (monoliths and beads). Selected materials are being tested as carriers for organic PCMs, namely polyethylene glycol (PEG) and coconut oil, as a bio-based alternative. Next steps include finishing beads and PCMs/scaffolds compounds characterizations.

Keywords: biomass, orange residue, aerogels, cryogels, phase change materials, pectin