Fast track for quantitative isolation of lignosulfonates from spent sulfite liquors

Abstract

In this study, a novel approach for isolation and purification of lignosulfonates from spent sulfite liquor was established. This approach involves sorption onto macroreticular non-ionic poly(methyl methacrylate) beads (XAD-7 resin) and subsequent desorption with organic solvents to obtain lignosulfonates of high purity. The method was optimized, verified and tested on four industrial lignosulfonate liquors from different processes and compared with an established ultrafiltration protocol. The method proved to be reproducible, robust and significantly faster than ultrafiltration.