Purification and fractionation of lignosulfonate in thin liquor by ceramic membranes

D. Humpert, M.Ebrahimi, University of Applied Sciences Mittelhessen; S. Kerker, P. Geigle, CMBlu Projekt AG; S. Demharter, Sappi Stockstadt GmbH; S. Schütz, F. Ehlen, MANN+HUMMEL GmbH, Germany; P. Czermak,Kansas State University, USA

Lignin is a phenolic macromolecule and belongs, beside cellulose, to the most abundant organic polymers on earth. It occurs mainly on plant cell walls, where it is responsible for the lignification. During paper and pulp production process lignin is separated from cellulose due to the fact that lignin is responsible for the yellowing of the paper. By molecule reduction as well as sulfonating the water‑insoluble lignin-molecules get soluble and can be separated from cellulose. As waste material of this procedure, a complex mixture of organic and inorganic components, arises. In this way, the paper industry produced every year more than 50∙106 metric tons of modified lignin, dissolved in the associated waste liquor. The majority is incinerated to produce energy, while a very small part is used to produce low value products like wood glue or wetting agent.

Within this work we investigate a) the performance of ceramic membranes with different properties (tubular and hollow fiber membrane geometries and various membrane molecular weight cutoffs: 1.0 kDa-800 kDa) and b) the performance of different membrane separation processes and parameters as well as operation modes and their effects on membrane fouling for the treatment of spent sulfite liquor. A further focus of the project is to concentrate and to fractionate the containing lignosulfonate molecules. The different concentrates have been characterized by size exclusion chromatography, UV-VIS spectroscopy and by enzymatic sugar quantification and the most promising membrane was selected for further investigations and optimization of separation/fractionation process...

Session: M5 - Ceramic Membrane Applications
Day: 15 March 2018
Time: 09:00 - 10:15 h

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