Solvothermal liquefaction of Tetra Pak waste into biofuels and AlO-carbon nanocomposite.

This study explores a novel solvothermal disposal technique of Tetra Pak waste for the co-synthesis of value-added bio-oil and alumina-carbon nanocomposite. The impact of residence time (10-50 min.), temperature (240-360 °C), and substrate-to-solvent ratio (1:4-1:10) on the solvothermal liquefaction of Tetra Pak waste with supercritical ethanol were investigated on a batch scale. Initially rise in operating temperature and residence time positively influenced the bio-oil yield. However, a decline in yield was seen beyond a certain point. A higher substrate-to-solvent ratio enhanced the bio-oil yield as the solvent demonstrated its effective capabilities to depolymerize the feedstock. The favorable condition for the highest bio-oil yield (34.41 %) and HHV (30.51 MJ/Kg) were found to be at 320 °C, 30 min, and a substrate-to-solvent ratio of 1:10. The synergetic effect of solvent (ethanol) and aluminium present in Tetra Pak leads to the formation of in-situ generated active hydrogen that enhances the bio-oil yields and inhibits residue formation. XRD and XPS analysis confirms the transformation of aluminium from (Al ) to (Al ) in the presence of ethanol forming in-situ generated alumina-carbon nanocomposite that has the potential to be used as a catalyst. NMR, GC-MS, and FTIR analysis confirmed the richness of bio-oil in various organic compounds including alcohol, esters, ketones, ethers, acids, and phenols. The recovered ethanol from the process exhibits a significant potential to be reused as a solvent or as a fuel additive.