SEPARATION OF LIGNIN FROM PLANT MATERIAL

摘要

Technology for separating lignin from alkaline solutions which arise in production of cellulose is presented. Isolated lignin can be applied, for instance, for production of carbon fibre, adhesives and binding materials, antioxidants and organic chemicals. Starting materials are non-woody plant materials, from which lignin is dissolved by sulphur free alkaline solutions at temperatures below 130°C. Lignin is precipitated by acid, and purified by hydrolyzing hemicellulose by acid or by enzymatic reactions or a combination of these. Lignin separated has a closely similar structure as lignin in plant material, and its content of functional atom groups can be controlled by changes in processing conditions.