▎ 摘　　要

NOVELTY - The membrane system has a nanofiltration membrane removing lignin from black liquor. The nanofiltration membrane has a first macroporous polymer substrate and a first graphene oxide membrane covering the first macroporous polymer substrate. The first macroporous polymer substrate has a polymer with aryl groups. The first macroporous polymer substrate comprises one of poly (sulfone) and poly (ethersulfone). USE - Membrane system for concentrating black liquor to remove lignin. ADVANTAGE - The membrane system can be resistant to high pH as well as resistance to fouling at transmembrane pressures of about specific bar. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for processing black liquor; and (2) a method for manufacturing a membrane system. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of membrane system for fabricating a graphene oxide membrane.