An ecofriendly and sustainable method for efficient cleaning of raw cashmere fiber with enzymes in SCF-CO2

Abstract

An efficient and ecofriendly method to remove impurities from raw cashmere fiber was constructed by employing various biological enzymes (lipase, cellulase, pectinase and protease) to form reverse microemulsion in supercritical carbon dioxide. An investigation and optimization of various parameters, such as the dosage of biological enzymes, cleaning temperature, pressure and duration for this method were performed according to the whiteness and weight loss of the treated samples. Then the proposed method was further validated by energy dispersive X-ray spectrometry (EDS), scanning electron microscopy (SEM) analysis to verify the impurity removal from cashmere fiber. Moreover, the aggregation structure and properties of cleaned cashmere fiber were also investigated by X-ray powder diffraction (XRD), strength measurement, moisture absorption testing and thermal analysis (TG-DTG). The results declare that, via forming a type of (W+enzymes)/SCF-CO2 microemulsion to transfer the biological enzymes into supercritical medium, various impurities from raw cashmere fiber could be efficiently decreased and removed, which cleaning performance was better than a conventional control process. The cleaning efficiency for various impurities was notably influenced by the dosages of the applied enzymes and system parameters, which could be improved at an appropriate condition in SCF-CO2. Furthermore, the cleaning feasibility, reliability and efficiency of the enzymatically catalyzed method for raw cashmere fiber was successfully verified by SEM, EDS, XRD, TG-DTG, tensile strength analysis, and a supercritical cleaning mechanism for raw cashmere was further proposed.

Keywords

• Supercritical carbon dioxide
• Raw cashmere fiber
• Reverse microemulsion
• Enzyme
• Impurity removal