Decolorization manner null of melanoidin coloration

摘要

PURPOSE:To make it possible to regenerate active carbon fibers, by decoloring a melanoidin-containing solution with polyacrylonitrile based active carbon fibers, treating the fibers with an alkali solution and treating the resultant fibers with a gas at a specific temperature. CONSTITUTION:A melanoidin-colored solution, e.g. tryptophan melanoidin solution, etc., is decolored with polyacrylonitrile based active carbon fibers. The above-mentioned active carbon fibers are then washed with hot water and treated with an alkali solution, e.g. 0.1-4.5wt% aqueous solution of sodium hydroxide, etc. the treated active carbon fibers are subsequently washed with water and treated with an acidic aqueous solution, e.g. hydrochloric acid, etc., for removing the residual alkali. The treated active carbon fibers are then washed with water or further fired and regenerated by treatment with a gas, e.g. nitrogen gas, etc., at 500-950 deg.C to enable the decolorization and regeneration of the afore-mentioned active carbon fibers.