Direct High-Temperature Dyeing Process

Because the extraction efficiency was determined by the direct comparison of dye concentration in the spiked dyebadi before and after the extraction, the higher SFE recoveries (e.g. efficiency >99%) should have relative standard deviations <1%. For the purpose of this study, >99% of recovery is sufficient to illustrate the effectiveness of the SFE technique. According to our experiments, no decomposition or breakdown of these disperse dyes was observed during SFE at the specified experimental conditions described atove. The restrictor flow rates of SC-CO2 often dominate the success of SFE, and can be varied to provide information on the dynamics of the extraction process. It is known that if the flow of supercritical fluid is sufficient to sweep the ceil void volume, the effectiveness of the extraction is enhanced. In fact, changing the flow rate is a simple way to determine the extraction efficiency (7). In this study, no obvious difference in extraction efficiency was observed at the SC-C02 flow rate of 2.0, and S.O mL/min. It is also noted that SFE of samples with high concentrations of water tends to plug fused silica restrictors 19). Therefore, a restrictor temperature controller was used in our experiments to avoid restrictor plugging. 

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