Microwave-assisted extraction and characterization by GC×GC-MS of solvolysis products of wind turbine blade materials

Objective This project aimed to develop analytical solutions to understand better the recycling of chemicals and valuable materials from new energy material waste, specifically focusing on wind turbine blades. This research is driven by the need to find sustainable methods for managing the end-of-life of renewable energy infrastructure components. Methods Wind turbine blades were subjected to 8-hour and 13-hour solvolysis treatments. The solvolyzed samples, referred to as solvolysis soups, were neutralized due to their extremely basic pH levels (around 14). Subsequently, the liquid phases were filtered to separate solid residues, while the solid phases were processed directly after neutralization. The products of these procedures were then subjected to solid-liquid and liquid-liquid microwave-assisted extraction (MAE) using a solvent mixture of hexane and methanol (10:3 ratio), followed by the addition of water (2.5 ratio) and centrifugation. The upper organic phase was collected, concentrated, and analysed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS), equipped with a non-polar column in the first dimension and a medium-polar column in the second dimension, connected with a cryogenic modulator. Results The MAE-GC×GC-MS methodology enabled the identification of approximately 60 molecules belonging to various chemical classes, such as aromatic, nitrogen-, and oxygen-containing compounds. The identification was based on mass spectral electron ionization (EI) database matching at 70 eV (≥800/1000) and the Linear Retention Index (LRI) window in the ±20 range, according to the non-polar 1D-GC LRI information reported in the NIST database and literature. The location of the investigated molecules on the 2D-GC plane was also considered. Conclusions This work contributes to the development of sustainable waste management practices in the wind energy sector, highlighting the potential for improved recycling techniques to efficiently recover valuable materials from wind turbine blades.