Unveiling the environmental costs of lignocellulosic film production with ionic liquids: the case of 1-ethyl-3-methylimidazolium acetate

Abstract

Sustainable plastic film alternatives require more than simply adopting “green” feedstocks. This study presents a comprehensive life cycle assessment (LCA) of lignocellulosic films produced using the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C₂C₁im][OAc]), including a single recycling cycle. Employing the ReCiPe 2016 framework, the environmental performance was evaluated across key impact categories: global warming potential (GWP), human health (HH), ecosystem quality (EQ), and resource scarcity (RS). The results reveal unexpectedly high environmental burdens, primarily driven by energy-intensive stages such as ionic liquid recovery, particularly freeze crystallisation and solvent evaporation. Electricity consumption and the production of the ionic liquid itself were consistently the dominant contributors across all categories, overshadowing the comparatively negligible impacts of lignin and cellulose. When benchmarked against commercial cellophane, the lignocellulosic films demonstrated substantially higher environmental impacts in every category assessed. These findings challenge the assumption that bio-based inherently equates to sustainable and highlight the urgent need for process optimisation, energy efficiency improvements, and integration of low-carbon power sources to unlock the true environmental potential of lignocellulosic film technologies.