High-efficiency and recyclability of ramie degumming catalyzed by FeCl3 in organic solvent.

Although traditional alkaline (TAL) process for ramie degumming is commonly used in the industry, it causes severe environmental concerns. In this work, an emerging organic solvent degumming process utilizing FeCl3 catalyst (FeCl3-OS) was developed in one step. The influences of FeCl3-OS system on fiber properties (e.g. residual gum content, tenacity, degree of polymerization (DP), etc.) were evaluated, and the recyclability of degumming solution was also studied. The results indicated that ramie fiber could be isolated with FeCl3-OS treatment (FeCl3 1.0 %, 200 ℃, 121 min), and the tenacity and residual gum content of refined fibers were 7.9 cN/dtex and 3.88 %, respectively. Fibers treated in FeCl3-OS system were endowed better moisture sorption (9.2 %) and higher yield (75.2 %) compared with that in TAL system. Moreover, fibers with five cycles' treatment possessed outstanding performances, that was 4.44 cN/dtex of tenacity and 4.33 % of residual gum content, which fulfilled the requirements of the spinning process.