Preparation Of Composite Hollow Graphene Microspheres And Study On The Adsorption Properties Of Formaldehyde

Formaldehyde is one of the primary indoor Volatile Organic Compounds(VOCs).The presence of formaldehyde in the room has extremely affected the human health and quality of our life.It has been the life demands of residents to eliminate indoor formaldehyde to a certain extent,and it is also the research topic by many researchers at home and abroad.In this paper,graphene materials and modified graphene materials are used to treat gaseous formaldehyde,and the treatment process involves adsorption and catalytic oxidation.In the study,hollow graphene oxide microspheres,hollow amine modified graphene microspheres and Ag-Co3O4-graphene composite nanomaterials were fabricated respectively.And the formaldehyde removal performances for each sample were tested and analysed.The graphene oxide(GO)and the monodispersed polystyrene(PS)microspheres were synthesized respectively by the Modified Hummers Method and the Dispersion Polymerization Method,after which the hollow gently reduced graphene oxide microspheres(HgRGOS)were prepared by PS hard templates.And the formaldehyde adsorption experiment in the paper was carried out by the self?assembly static adsorption device combining with spectrophotometry,where the test conditions were selected from three aspects:humidity,the content of formaldehyde and temperature in the adsorption device.The adsorption performance of HgRGOS sample were tested using the selected conditions,after that the adsorption mechanism were discussed simply.Finally,a series of hollow microspheres(HgRGOS)with the diameter of 1.5?m were obtained.The adsorption test showed that the adsorption capacity of HgRGOS sample reached 17.15 mg·g-1.And epoxy(or carboxyl)group on the surface of HgRGOS sample can absorb the gaseous formaldehyde,which may form R-CH2OH.The HgRGOS sample was modified with DETA,subsequently the amine modified graphene materials were tested for its formaldehyde adsorption performance,after which the adsorption mechanism of the amine group was discussed simply.In this part,the DETA-decorated HgRGOS(DETA-HgRGOS)sample were obtained,which possessed the same morphology as HgRGOS sample but a smaller BET surface area than HgRGOS sample.The adsorption performance test showed that the DETA-HgRGOS can reach the adsoption balance more rapidly and have a greater formaldehyde adsorption capacity than HgRGO sample.The adsorption capacity of HgRGOS sample reached 24.54 mg·g-1.There are abundant amine groups on the surface of DETA-HgRGOS sample,which can react with gaseous formaldehyde in the adsorption process.The-NH2 may react with formaldehyde to form-N?CH2(-NHZ+HCHO?-N=CH2),or-NH-R may react with HCHO to form-N(-R)CH2OH(-NH-R+HCHO?-N(-R)CH2OH).Ag-Co3O4-graphene composite nanomaterials were fabricated by four steps,including hydrothermal synthesis of graphene-CoC2O4 precursor,the thermal decomposition of precursor,silver oxide deposition and the last thermal decomposition with NZ protection.The adsorption process of graphene materials and the catalytic oxidation process of Ag-Co3O4 nanomaterials work together to remove the gaseous formaldehyde contaminant.Mesoporous Ag-Co3O4-graphene composite nanomaterials were obtained in this section,which displayed a good forrmaldehyde removal efficiency of 77.49%at 30?.