▎ 摘　　要

NOVELTY - Graphene oxide comprises an oxygen-containing functional group. The content of carboxyl group in the total oxygen-containing functional groups is 5% or more. USE - Graphene oxide is used in heavy metal-absorbing composition and device e.g. water purifier, water treatment device, air purifier, air conditioner, air mask and absorption filter (all claimed) used in absorption of heavy metal. ADVANTAGE - The graphene oxide has excellent heavy metal absorption performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacture of graphene oxide, which involves preparing graphene oxide aqueous solution, adding a carboxylic acid or its salt to the aqueous solution and mixing uniformly.