Within the scope of this research work, an efficient membrane-based process with ceramic ultrafiltration membranes was developed for the recovery of purified lignosulfonates from the spent sulfite liquor of chemical wood pulping. The aim was to separate the lignosulfonates from low-molecular organic impurities (sugar, carboxylic acids, etc.) and process chemicals, to concentrate them, and to make them available for a targeted further use. One further aspect of the project was the separation of the products (target molecules) of lignosulfonate degradation using ceramic membrane technology.