▎ 摘　　要

NOVELTY - Preparing graphene-carbon nanotube composite material comprises (i) adding graphite powder and multi-walled carbon nanotubes by constant stirring, adding concentrated acid, potassium permanganate slowly, stirring, allowing hydrogen peroxide to react with potassium permanganate, adding deionized water and centrifuging; (ii) adding oxidized graphite and carbon monoxide nanotubes into deionized water , ultrasonic stripping and dispersing; (iii) adjusting pH value by adding aqueous ammonia into solution, adding ethylenediamine and stirring; and (iv) filtering , washing and freeze-drying. USE - The composite material is used as adsorbent for extracting and detecting melamine, clenbuterol, sulfamethazine, indoleacetic acid, bambuterol, chlorphenazine, dicofol, 2,2-bis (4-chlorophenyl)-1,1-dichloroethane or fluorochlorothosulfone (all claimed). ADVANTAGE - The method is simple, has mild reaction conditions. The carbon nanotubes are covalently bonded to graphene sheets and has fluffy porous three-dimensional skeleton structure. DETAILED DESCRIPTION - Preparing graphene-carbon nanotube composite material comprises (i) adding graphite powder and multi-walled carbon nanotubes in weight ratio 4: 1-20: 1 by constant stirring, adding concentrated acid, potassium permanganate slowly, stirring at room temperature for 6-48hours, allowing hydrogen peroxide to react with potassium permanganate, adding deionized water and centrifuging to obtain oxidized graphite and carbon monoxide nanotubes, where weight ratio of potassium permanganate and hydrogen peroxide is 1g:3-6 g: 5-10 ml; (ii) adding oxidized graphite and carbon monoxide nanotubes after centrifugation into deionized water , ultrasonic stripping oxidized graphite into graphene oxide and uniformly dispersing carbon nanotubes and graphene; (iii) adjusting pH value of solution to 9-10 by adding aqueous ammonia into dispersed carbon nanotubes and graphene solution, adding ethylenediamine and stirring at 80-95 degrees C for 3- 24 hours; and (iv) filtering , washing with deionized water until pH value is 7 and freeze-drying