Lca of Aerogel Production Using Supercritical Gel Drying: from Bench Scale to Industrial Scale

Abstract

In the last years, many studies on Drug Delivery Systems (DDS) were performed with the aim of improving the dissolution rate of poorly water-soluble drugs. Nanostructured aerogels, characterized by open pore structures and high surface areas, were frequently used as substrates where drugs can be adsorbed. In particular, different researches focused their attention on polysaccharide aerogels, which are biodegradable and biocompatible and, therefore, are good candidates to support active substances in DDS. In this work, maize starch aerogels were produced on different scale plants using a three-step process: first, the gel was prepared using an aqueous solution, then water was replaced by ethanol forming an alcogel and finally, carbon dioxide at supercritical conditions was used as non-solvent to dry the alcogel and obtain the aerogel. An analysis aimed at evaluating and minimizing, using Life Cycle Assessment (LCA) methodology, the environmental impacts of aerogel production on five different scale plants was carried out. The impacts related to the production of 1 kg of starch aerogel on two different scales (vessel internal volumes, V, equal to 0.5 L and 5.2 L) were evaluated using primary data; moreover, a modelling of the emissions due to productions on industrial scales (V equal to 50, 100 and 200 L) was also performed. Data were analysed using SimaPro 8.0.5 software, whereas the Ecoinvent 3.1 database and primary data were used for the life cycle inventory, according to the reference standard for LCA (i.e., ISO 14040-14044). A “from gate to gate” approach was followed; therefore, the system boundaries were set from starch powder transportation to aerogel production. The IMPACT 2002+ method was used to evaluate the effect of the production on the midpoint and damage impact categories.