Characteristics and Properties of Soda Lignin Obtained from Aspen Wood By-Products

Abstract

In the work, soda lignin was obtained under laboratory alkaline delignification conditions from aspen sawdust. The chemical composition and the surface-active properties of this lignin in aqueous solutions were studied. The high indices of Klason lignin and the content of methoxyl groups indicated the insignificant presence of non-lignin admixtures, including lignocarbohydrate complexes, in the purified lignin. It was shown that aspen lignin was a surface active substance, the surface activity of which at the water-air interface grew with falling the solution рН values. Simultaneously, with decreasing рН, the particle sizes of aspen lignin in the aqueous solutions increased, but zeta potential of the lignin particles had the tendency to decrease.