▎ 摘　　要

NOVELTY - Filtration apparatus comprises support substrate and graphene oxide membrane are provided on the support substrate. The graphene oxide membrane includes multiple of graphene oxide sheets, each of the graphene oxide sheets covalently coupled to chemical spacer, each of the graphene oxide sheets is not covalently crosslinked to the adjacent graphene oxide sheet, graphene oxide membrane has first lactose rejection rate of 50% with first 1 wt.% lactose solution at room temperature and after graphene oxide membrane is contacted with solution that is 80?oC for period of time. The graphene oxide membrane has second lactose rejection rate of 50% with second 1 wt.% lactose solution at room temperature. USE - Filtration apparatus. ADVANTAGE - The filtration apparatus has low cost, high chemical stability, strong hydrophilicity, and compatibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for processing black liquor, which involves flowing black liquor through filtration apparatus, where black liquor comprises lignin, sodium sulfate, sodium carbonate, sodium hydrosulfide, sodium thiosulfate, sodium hydroxide, or combination.