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An in-depth study of the oxidative liquefaction process has been provided to degrade the polymeric waste from personal protective equipment (PPEs) and wind turbine blades (WTBs). Thermogravimetric investigations demonstrate that WTBs have three prominent peaks throughout the degradation, whereas PPEs display solitary peak features. Experiments are carried out employing specific experimental design approaches, namely the Central Composite Face-Centered Plan (CCF) for WTBs and the Central Composition Design with Fractional Factorial Design for PPEs in a batch-type reactor at temperature ranges of 250–350 °C, pressures of 20–40 bar, residence times of 30–90 min, H2O2 concentrations of 15–45 %, and waste/liquid ratios of 5–25 % for WTBs. These values were 200–300 °C, 30 bar, 45 min, 30–60 % and 5–7 % for PPE. A detailed comparison has been provided in the context of total polymer degradation (TPD) for PPE and WTBs. Liquid products from both types of wastes after the oxidative liquefaction process are subjected to gas chromatography with flame ionization detection (GC-FID) to identify the existence of oxygenated chemical compounds (OCCs). For WTBs, TPD was 20–49 % and this value was 55–96 % for PPE while the OCC yield for WTBs (36.31 g/kg - 210.59 g/kg) and PPEs (39.93 g/kg - 212.66 g/kg) was also calculated. Detailed optimization of experimental plans was carried out by performing the analysis of variance (ANOVA) and optimization goals were maximum TPD and OCCs yields against the minimum energy consumption, though a considerable amount of complex polymer waste can be reduced and high concentrations of OCC can be achieved, which could be applied for commercial and environmental benefits. • Thermal degradation of wind turbine blades takes place in three distinct stages. • Personal protective equipment's solidarity peak highlights uniform composition. • Oxidative liquefaction has potential to recycle both simple and complex waste streams. • Polymer degradation of wind turbine blades is non-linear with increasing temperature. • Oxidant concentration increases polymer degradation, adversely affects chemical yield. [ABSTRACT FROM AUTHOR]

According to the latest reports, estimated values of 50,000–66 000 t of end-of-life wind turbine blades (WTB) are expected to be decommissioned in Europe in 2025–2030, posing a significant threat from the environmental and waste management perspectives. This study aims to present the preliminary Life Cycle Assessment (LCA) with sensitivity and uncertainty analysis of the lab-scale oxidative liquefaction process of the WTB, as the original method to recover the high-quality glass fibers with simultaneous production of the secondary chemicals: phenols, ketones, acids, and fatty acids, from the oxidation of the epoxy resin from the polymer matrix. The LCA is based on the experimental results of the oxidative liquefaction process carried out on a laboratory scale using a Parr 500 ml batch reactor, at two different conditions sets for the functional unit (FU) of 1 kg of treated WTB. Each of the analyzed scenarios resulted in higher impact indicators compared to the landfilling. The highest quality fibers were obtained at 350 °C and 40 wt % H 2 O 2 content resulted in 5.52 ± 1.20 kgCO 2 eq Climate change impact and 97.8 ± 20.6 MJ of Resource use, fossil per kg of recycled WTB. The lowest quality fiber recovered in char, yet well separated from the matrix obtained at 250 °C and the lowest H 2 O 2 content resulted in 0.0953 ± 0.487 kgCO 2 eq Climate change impact and 8.84 ± 7.90 MJ of Resource use, fossil per kg of recycled WTB. The hot spot and sensitivity analysis indicated, that the oxidizer for the process – hydrogen peroxide, when acquired as a shelf product causes a significant burden on the whole process, with sensitivity ratios on the total impact indicators varying across the categories from 0.56 to 0.99. Substitution of H 2 O 2 with theoretical 0-input oxidizer allowed to significantly lower environmental load of the recycling process, which in all of the analyzed scenarios presented environmental benefits compared to landfilling with recovery of the glass fiber and secondary chemicals. • The LCA of oxidative liquefaction of wind turbine blades was studied. • Climate change impact category of recycled fibers varied at 0.00953–5.52 kgCO 2eq. • Sensitivity analysis showed that the biggest impact was caused by hydrogen peroxide. [ABSTRACT FROM AUTHOR]