Bio-based Ionic liquids and Natural Deep Eutectic Solvents: development of new media and exploration of new processes for the valorization of food industry biomass wastes

The green chemistry concept could be applied as a potential tool to drive the transition from linear economy to circularity, which among its various aspects includes the transformation of biomass wastes for better utilization leading to closing loops of these new renewable materials. In this scenario, to enhance the sustainability of the designed processes, the employment of green solvents like ILs and DESs, with particularly attention to bio-ILs and NADES represents an intriguing alternative to classical solvents. Indeed, their particular features and the possibility of creating a virtually limitless number of cation/anion pair for ILs and HBA/HBD combinations for DESs allow to fine tune their physio-chemical properties in order to make them suitable for all the desired applications. In this context, my PhD project focused on two main purposes. The first aim included the preparation of well-known ILs and DESs already reported in literature and their subsequent application, either alone or in combination, in valorization processes of food industry biomass wastes in order to recycle and give them a new value. In particular, my attention was focused on three different biomasses: chestnut shell wastes, apple and cherry pomaces. More in details, phenolic compounds that can be easily reintroduced in the market thanks to their many biological activities have been extracted applying both classical heating method and greener microwave assisted approach. Moreover, the fractionation of these lignocellulosic biomass considered the most promising, abundant, inexpensive, renewable, and natural feedstock to produce and supply alternative fuels, chemicals, and materials, led to the successful obtainment of cellulose or lignin enriched materials. Either the composition of phenolic extracts and of the fractions obtained from the lignocellulosic biomass treatment have been deeply characterized and investigated. Instead, the second aim of the project involved the design, the synthesis and the characterization of new bio based ILs, considering both the anion (levulinate based-ILs showing different cation counterparts) and the cation (mono and dicationic esters of betaine and L-carnitine bromides bearing different alkyl chain length from C2 to C18) with possible application in separation or extraction processes.