Cleaning contaminants from cotton textiles using compressed liquid CO2 and co-solvent mixtures.

Liquid CO2 (L-CO2) has emerged as a safe and sustainable alternative to conventional organic solvents in dry cleaning owing to its non-toxic, non-flammable, and environmentally friendly nature. However, the compounds that can be removed from the fabrics by L-CO2 are unknown. In this study, we optimized the temperature, flow rate, and co-solvent for L-CO2 dry cleaning and identified the compounds that can be removed by this method using gas chromatography-time-of-flight mass spectrometry. A 7:3 (v/v) isopropanol(IPA)/water mixture was the optimal co-solvent mixture. Our L-CO2+IPA/H2O dry cleaning method exhibited high efficacy in removing a diverse range of substances, such as cholesterols, fatty acids, N-compounds, sugars, and sugar derivatives. In particular, 100% of the cholesterols were removed from the stained fabric.