The conventional dyeing of textiles requires that an excess of dye is dissolved or in some way "taken-up" in an aqueous or solvent solution. The dye mix is then pumped into a vat containing holding the textile. Typically there is agitation or the dye is recirculated several times through the cloth. At the end of the cycle, the dye mix is pumped to the waste treatment facility. Dyes are notoriously difficult to treat. The process is decidedly unfriendly to the environment.
The use of supercritical CO2 in textile dyeing is an environmentally friendly alternative. Instead of using an aqueous or solvent solution to "take-up" the dye, supercritical CO2 is used. The process proceeds in the same manner as the conventional method, but instead of sending the spent mix to the waste treatment facility, the supercritical CO2 /dye mix is depressurized. The CO2 changes to a gas and all the spent dye falls out and can be reused. In production systems the CO2 is recycled, providing for a completely closed system and an entirely environmentally friendly approach to textile dyeing.
You have small amounts to process, or you need to perfect your method.