Rapid and energy-saving preparation of ramie fiber in TEMPO-mediated selective oxidation system

Although oxidation systems were many and varied, alkali peroxide oxidation system was the only one used for ramie degumming in previous studies. In the work reported here, the possibility of ramie degumming in TEMPO-mediated selective oxidation system was studied. Results revealed that ramie fiber can be extracted by using TEMPO-mediated oxidation treatment (NaClO 2 mmol/g; 15 min; 20 similar to 25 degrees C) followed by a low concentration NaOH scouring (2.5%, 100 degrees C, 60 min) and a reducing process. Fiber degummed in TEMPO-mediated selective oxidation system showed better tensile properties and lower acid group contents compared with that in alkali peroxide oxidation system. The required time for TEMPO-mediated selective oxidation degumming was about 125 min, which was 55 min shorter than hydrogen peroxide system. Moreover, the COD value of wastewater in TEMPO-mediated selective oxidation degumming was 28% lower than that in alkali peroxide oxidation degumming.