Oxidation Removal of Lignin-degradation Products by Zero-valent iron Activated Persulfate

Abstract

A total of nine major lignin-degradation products were selected in this study for oxidation removal by a new detoxification technology-advanced oxidation process of zero-valent iron (ZVI) activated persulfate (PS). This procedure attempts to determine the effect of lignin-degradation products on ethanol fermentation during the bioethanol production process. Results indicate that the optimal oxidation conditions were pH5.0, 25°C, ZVI concentration of 1.0 g/L, and PS concentration of 1.5 g/L based on 0.1 g/L vanillin as the model of the lignin-degradation products. The oxidation effect of the eight other major lignindegradation products on the optimal conditions was also studied. Results show that their oxidation removal efficiency values were remarkable. Except for vanillin (99%), vanillic acid (97%), 4-hydroxybenzaldehyde (93%), and 4-hydroxybenzoic acid (81%), the removal efficiencies values of the five other lignin-degradation products (i.e., syringaldehyde, syringic acid, 3,4dihydroxybenzoic acid, p-coumaric acid, and ferulic acid) were all 100%. The dominant active species during the advanced oxidation process was sulfate radicals. Therefore, the ZVI/PS system is a suitable approach for the oxidation removal of lignindegradation products.