Exploration of mechanisms of lignin extraction by different methods

Due to a combination of rapid consumption of fossil fuels such as coal and oil with gradual increase in people's awareness of environmental protection, the research for substitute resources has become a hot spot. Because of their abundant sources of raw materials, fast regeneration rate and low greenhouse gas emissions, biomass resources have drawn much attentions. Woody fiber is one of the richest renewable biomass on earth, in which lignin is the largest renewable aromatic compound resource, therefore possessing a very broad application prospect. Nowadays, a large number of reviews on lignin extraction methods have been written while there are few explorations on the mechanisms behind those methods. Thus, the principles of several typical lignin extraction methods were described in this article. These principles were explored with the hope to provide a reference for future development of lignin extraction.