Preparation Of Graphene Composites And Investigations Of Their Application In Sewage Treatment

Pollution especially water pollution is a common problem around the world. With rapid development of the industry, the problem is getting worse for discharge of hazardous chemicals. Therefore the problem of water pollution has become one of the social problems.Recently, graphene imerged as a new carbon material owing to its large surface, good thermal and electric conductivity, and stong mechanical properties. Graphene-based polymer materials and graphene-inorganic hybrids have potential application in treatment sewage.In this paper, two graphene composites--graphene/polymer and graphene/inorganic hybrids were prepared and their adsorptive performance and catalytic degradation property were studied. The main contents are as follows:(1) Preparation of GO-PANI composite and its adsorption of Pb2+(1) Preparation of GO-PANI composite and its adsorption of Pb2+Polyaniline(PANI) chains are grafted at the edge of GO sheets by in-situ chemical oxidation polymerization with the p-phenylenediamine attached to GO sheets as anchor sites. The structure and morphology of the GO-PANI composite are characterized by Fourier-transform infrared spectroscopy(FTIR) and Raman spectroscopy,thermogravimetric analysis(TGA), X-ray diffraction(XRD), elemental analysis and transmission eletron microscopy(TEM). The GO-PANI were used to adsorb Pb(II) and methylene blue(MB) from aqueous solution. The results showed that the adsorption kinetics and isotherms followed pseudo-second-order and Langmuir isotherm model,respectively. GO-PANI exhibited a superior adsorption capacity for Pb(II)(1416 mg/g)compared with other absorbents. The process of adsorption for Pb(II) onto GO-PANI is spontaneous and endothermic at 288 K, 298 K and 308 K. In mixed system, the adsorption capacity for MB and Pb(II) onto PANI-GO achieve to 544 mg/g and 1004 mg/g,respectively. This study provides a promising PANI-GO composites with an efficient adsorption property for MB and Pb(II).(2) Preparation of GO/NH2-MIL-53 composite and its visible light catalytic degradation of MBFirstly polystyrene(PS) microspheres with positive charge were prepared. GO sheets were adsorbed to the surface of PS microspheres through electrostatic interactions. GOsheets at the surface of PS microspheres were reduced and treated by diazonium of p-aminobenzoic acid to bring more carboxyl functional groups on the surface of graphene sheets. Upon addtion 2-aminaterephthalic acid and Al3+ to the above PS microspheres dispersion, a new graphene/MOF was synthesized under hydrothermal conditions. Finally,the hollow graphene/MOFs materials are prepared by resolving graphene/MOFs in DMF to remove PS core. The structure and morphology of the hollow graphene/MOFs were characterized by PXRD, IR, TGA, and SEM. And the degradation of methylene blue for the GO/NH2-MIL-53 composite were tested and characterized in visible light. The study displayed that the photocatalytic activity of MB for the GO/NH2- MIL-53 composite was greatly improved. Compared with NH2-MIL-53, the degradation rate of the GO/NH2-MIL-53 composite was almost increased to1.85 times.