Aiming at the effect of lignin-degradation products on ethanol fermentation during the bioethanol production process

six kinds of typical lignin-degradation products (vanillin

syringaldehyde

4-hydroxybenzaldehyde

vanillic acid

syringic acid and 4-hydroxybenzoic acid) were selected to oxidative removal by a new detoxification technology-advanced oxidation process of heat-activated persulfate. The oxidation removal conditions and its oxidation mechanism were also investigated. The results indicated that the optimal oxidation conditions were pH 6.0

80℃

and the persulfate concentration of 1.5 g·L-1 based on 0.1 g·L-1 vanillin. On the basis of the optimized conditions

the oxidation effect of other five of typical lignin-degradation products was studied. The results showed that the effects of oxidation removal were obvious. The removal ratio of vanillin

4-hydroxybenzaldehyde

vanillic acid and syringic acid reached to 100% within 1 h

while that of syringaldehyde reached to 100% within 2 h. The study of oxidative mechanism was to indirectly decide which the main active species was in the reaction process by the addition of radical scavengers of methanol and t-butanol. The results showed that the main active species were sulfate radicals. Therefore

using heat-activated persulfate is a good way for oxidative removal of the lignin-degradation products.