Preparation method of lignin-based activated carbon fiber with large specific surface area

The invention provides a preparation method of a lignin-based activated carbon fiber with the large specific surface area. The preparation method of the lignin-based activated carbon fiber with the large specific surface area comprises the following steps: (1) heating for melting lignin, and carrying out melt spinning on the lignin to obtain a lignin-based fiber; (2) carrying out chemical thermostabilization treatment on the lignin-based fiber by adopting hydrochloric acid, so that a non-melting lignin-based fiber is obtained; (3) heating the non-melting lignin-based fiber to 100-1200 DEG C from the room temperature, carrying out heat preservation for one hour, stopping heating, and carrying out natural cooling, so that a lignin-based carbon fiber is obtained; and (4) activating. By virtue of the treatment manner, the obtained lignin-based activated carbon fiber has excellent physical and chemical properties, the specific surface area is greatly increased, adsorption and desorption capabilities are respectively improved, and the lignin-based activated carbon fiber can be widely applied to the fields of environment protection, electronics, medical sanitation and chemical engineering due to the special surface chemical structure and the physical adsorption characteristic; meanwhile, the preparation method of the lignin-based activated carbon fiber with the large specific surface area is easy to operate, low in energy consumption, and short in time and has a relatively good industrial application prospect.