CO₂ dry cleaning: Acoustic cavitation and other mechanisms to induce mechanical action

High pressure carbon dioxide (CO₂) is a potential solvent for textile dry cleaning. However, the particulate soil (e.g. clay, sand) removal in CO₂ is generally insufficient. Since cavitation has been proven to be beneficial in other CO₂ cleaning applications, this study aims to investigate the possibility of improving the performance of CO₂ textile dry cleaning by using ultrasound or other mechanisms to induce the mechanical action such as bubble spray and jet spray. In the experiments, several types of textiles soiled with a mixture of motor oil and soot were cleaned using 1 L and 90 L CO₂ dry cleaning set-ups. Using either ultrasound, stirring, liquid spray or bubble spray does not give a significant improvement on particulate soil removal from textile. It was also found that the additional use of ClipCOO detergent does not give a significant improvement on particulate soil removal either. The cleaning performance of CO₂ is 50% lower than that of PER and thus another method to increase the particulate soil removal in CO₂ textile dry cleaning still needs to be developed.