The depletion of biodiversity and global warming make green technology and a bioeconomy imperative. The biopolymer lignin has enormous promise. Every year, technical lignin is extracted and utilized for chemical and heat recovery. Lignosulfonates are the primary constituent of discarded sulfite liquor, which are essential to the biorefinery sector and the emerging bioeconomy. Nevertheless, the usage of sulfite pulping effluent is limited and chemical analyses become more difficult due to the presence of additional components and separation difficulties. As a result, novel techniques for the isolation and purification of lignin for the use in industry and analysis are being developed.
This chapter discusses the difficulties and viewpoints involved in creating practical lignin manufacturing processes while reviewing techniques for separating lignin derivatives from pulping spent liquor, sulfite spent liquor, kraft black liquor, bagasse, corn stover, jute sticks, wood, etc. While ultrafiltration is thought to be an industrially viable method for extracting lignosulfonate from sulfite spent liquors, other extraction processes, such as flat sheet-supported liquid membrane (SLM), microwave-assisted sulfonation, supercritical water hydrolysis, and ion exchange, are designed for commercial-scale lignin isolation. There is also a discussion of lignin extraction from naturally occurring lingo-cellulosic materials both with and without an acid hydrolysis method.
