Life Cycle Assessment of γ-CD-MOF-1: Environmental Implications of Green Metal-Organic Framework Synthesis

Abstract

We report the first cradle-to-gate life cycle assessment (LCA) of γ-CD-MOF-1, a crystalline metal-organic framework (MOF) synthesized from γ-cyclodextrin (γ-CD) and potassium hydroxide (KOH) via vapor-diffusion crystallization. Production of 1 kg of γ-CD-MOF-1 yields an estimated 83.2 kg CO2 equivalent, making it one of the lower-impact routes reported. Contribution analysis reveals a distinctly category-dependent environmental profile governed by two principal inputs. Methanol, serving as both a reaction medium and washing solvent, dominates climate and resource categories, accounting for 67.2% of global warming potential (GWP) and 81.4% of fossil resource scarcity (FRS), whereas γ-CD drives ecosystem impacts, contributing 95.3% of land use (LU) and 81.4% of terrestrial ecotoxicity (TE). The most compelling advantage is observed in human carcinogenic toxicity (HCT), with γ-CD-MOF-1 showing a value of 0.869 kg 1,4-dichlorobenzene (1,4-DCB) equivalent, one order of magnitude lower than widely studied MOFs. Increasing methanol recovery to 80% reduced GWP by 53.7%, while LU remained unchanged. These screening-level results show that bio-derived MOFs should not be directly labeled as sustainable and that solvent strategy can be as important as precursor origin.