Abstract:

By changing the solvent system and pretreatment conditions, a series of studies were carried out on the electricity generation performance of the four types of lignin (enzymatic hydrolysis lignin(EHL), alkaki lignin(AL), sodium ligninsulfonate(SL) and furfural residue(FR))in direct biomass fuel cells. The UV spectrum, FT-IR spectrum and ¹H NMR spectrum before and after the reaction of alkali lignin were analyzed. The results showed that the alkali lignin exhibited the best power generation performance, the open circuit voltage(OCV) could reach 392.7 mV, and the peak power density(PPD) was 0.198 W/m². And lignin had the best power generation performance in NaOH solution. Water bath heating pretreatment could improve the power generation performance of lignin. The higher the temperature and the longer the treatment time, the better the power generation performance of the lignin would be. When lignin was irradiated with ultraviolet light, the electricity production performance increased first and then decreased with the passage of time. The electricity production performance was the best when it was treated for 24 hours. The OCV could be increased to 431.2 mV, and PPD was increased to 0.371 W/m². After the oxidation reaction in the fuel cell, the benzene ring structure of lignin had been destroyed to a certain extent, and the hydroxyl group on the benzene ring had been oxidized to a carbonyl structure. The UV absorption peak of alkali lignin produced red-shift and color enhancement effects. And in the FT-IR spectrum, the carbonyl absorption peak was enhanced. Especially, the signals of aromatic protons, phenolic hydroxyl groups and aliphatic hydroxyl groups were weakened in ¹H NMR spectrum.

Key words: biomass, alkali lignin, pretreatment, generate electricity