Study on the efficiency and recyclability of Fenton-MnFe2O4 for the degumming of hemp fibers.

ABSTRACT

Traditional alkali degumming (TAL) has been widely used for hemp degumming; however, the produced degumming waste liquid pollutes the environment. For this phenomenon, an improved Fenton oxidation degumming process was developed in this study, that is, MnFe2O4 (Fenton-MnFe2O4) was added to the Fenton system. The purpose was to reduce the reaction time and the addition of chemical reagents, and reuse the added MnFe2O4. The effects of the Fenton-MnFe2O4 system on fiber properties (such as residual gum rate, and breaking strength) and the recyclability of MnFe2O4 were studied. The results indicated that the hemp fiber could be separated by Fenton-MnFe2O4 treatment (5.30% H2O2 (w/w), 0.310% FeSO4·7H2O (w/w), 0.040% MnFe2O4 (w/w), 40.0 °C, 40.0 min). The breaking strength of the refined fiber was 18.22 cN per dtex, and the residual gum rate was 5.47%. Compared with the TAL system, the time was shorter, energy consumption was less and pollution was smaller. In addition, the fiber treated with MnFe2O4 after five cycles still showed excellent properties, namely, 15.76 cN per dtex breaking strength and 7.79% residual gum rate, which met the needs of the spinning process. Therefore, Fenton-MnFe2O4 show great development potential in hemp fiber degumming.