▎ 摘　　要

NOVELTY - The method involves flowing black liquor comprising lignin through a filtering membrane. The filtering membrane comprises a substrate and the stacked graphene oxide layers forming a graphene oxide membrane covering the substrate. A portion of the lignin is removed from the black liquor through the filtering membrane. The permeability of the filtering membrane as measured by water permeation flux as a function of transmembrane pressure does not decrease after flowing the black liquor through the filtering membrane. The portion of the lignin removed from the black liquor is 90% of the lignin present in the black liquor. The portion of the lignin removed from the black liquor is between 90% and 99% of the lignin present in the black liquor. USE - Method for processing black liquor. ADVANTAGE - The polymer with a relatively high hydrophilicity, which can result in higher water flux and can provide strong adhesion to the graphene oxide membrane is used. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating the process for fabricating a graphene oxide membrane.