The effect of oxidation–reduction potential on the degumming of ramie fibers with hydrogen peroxide

Oxidation–reduction potential (ORP) was applied to monitor and control the oxidation reaction of peroxide hydrogen in the degumming process of ramie fibers. The effects of original pH, hydrogen peroxide dosage, oxidation temperature, and reaction time on ORP variations and fiber degumming efficiency were fully investigated. Central composite design method was used to optimize the degumming process. The optimum operating parameters were original pH 11.0, hydrogen peroxide dosage of 5.0 g/L, oxidation temperature of 85°C, and reaction time of 60 min, respectively. When the ORP value in the solution varied from +320 to +350 mV, it could achieve desired and reasonable degumming result. Under this range, the residual gum percentage of treated fibers was relatively lower and the mechanical property was better compared with other ORP values. This study could be instructive in online monitoring and control of ramie fiber preparation process using ORP as an indicating factor.