Life cycle considerations for membrane fabrication: Linking polymer–solvent selection to plastic persistence and end-of-life trade-offs

Polymeric ultrafiltration and microfiltration membranes are crucial for water treatment but produce growing amounts of plastic waste at end-of-life (EoL). While recent studies emphasize green solvents and bio-based polymers, the influence of disposal pathways and material persistence remains insufficiently addressed. In this study, a comparative life cycle assessment, following ISO 14044 guidelines, was performed to evaluate twelve fossil-based, hybrid, and bio-based polymer–solvent systems fabricated via non-solvent-induced phase separation (NIPS). The system boundary covers a partial cradle-to-grave scope, intentionally excluding the use phase to isolate material-level contributions to fabrication and end-of-life (EoL) burdens. Three EoL scenarios were assessed: landfilling, incineration, and incineration with fly ash extraction (FAE) recovery. Fabrication-stage material inputs and electricity drive most environmental burdens, while EoL management introduces scenario-dependent trade-offs between climate-change and aquatic-toxicity impacts. Landfilling of bio-based membranes minimizes Global Warming Potential through carbon sequestration, but significantly increases marine eutrophication by 10–17% due to nutrient leaching during degradation. Conversely, incineration mitigates eutrophication impacts but introduces ∼1% carbon penalty from the combustion of polymers. Persistent fossil polymers, such as polysulfone (PS) and polyvinylidene fluoride (PVDF), exhibited environmental half-lives exceeding 1000 years, highlighting a “persistence debt” under landfill disposal. By integrating LCA results with polymer degradation kinetics, cellulose acetate (CA) membranes fabricated with γ-valerolactone (GVL) emerged as the most balanced transition pathway. This study highlights the need for persistence-aware, EoL-integrated membrane design to advance circularity in water treatment technologies.

Duke Scholars

Author Mark Wiesner Civil and Environmental Engineering

Author Nathan Bossa Civil and Environmental Engineering