▎ 摘　　要

NOVELTY - Hybrid material comprises graphene and iron oxide. USE - The hybrid material is useful for removing heavy metal (arsenic, cadmium, mercury, antimony or bismuth) in wastewater (all claimed). ADVANTAGE - The hybrid material: has magnetic properties and high dispersibility; is a fine and uniform hybrid material, which may be applied to mass production; and has excellent pH stability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) manufacturing the hybrid material, comprising (a) preparing a graphene oxide, (b) dispersing the graphene oxide in water to prepare a first dispersion, (c) adding divalent iron and trivalent iron to the first dispersion to prepare a second dispersion, (d) adjusting pH of the second dispersion to 8-11 at 25 degrees C, (e) increasing the temperature of the second dispersion up to 80-110 degrees C and (f) adding a reducing agent to the second dispersion to prepare a hybrid material including graphene and iron oxide; and (2) an apparatus for treating wastewater by using the hybrid material.