Preparation Of Graphene-based Composites And Their Applications In Wastewater Treatment

With the aggravation of water environmental pollution,more and more attention have been paid to the wastewater treatment,especially for dye wastewater and oil-containing wastewater.As one kind of important advanced oxidation technologies,heterogeneous Fenton catalytic oxidation has been widely used in the pretreatment and advanced treatment of dye wastewater.And catalyst with high catalytic activity is the key.Adsorption is also an important type of wastewater treatment and is used in many practical wastewater treatment projects,while adsorbents are the key points.Based on the excellent properties of graphene oxide(GO),this thesis mainly focused on two aspects of researche:(1)Preparation of Fe3-xCuxO4/GO(0?x?0.1)nanocomposites and catalytic degradation of p-nitrophenol(p-NP)in water.(2)Preparation of graphene aerogel(GA)and graphene aerogel doped with multi-walled carbon nanotubes(GMA)and their adsorption capacity for organic compounds.The main conclusions are as follows:(1)The Fe3O4/GO with different GO contents and Fe3-xCuxO4/GO(0?x?0.1)nanocomposites with different Cu doping amounts were prepared by co-precipitation method and used as heterogeneous Fenton catalyst for the degradation of p-NP.Fe3O4/GO nanocomposite has the best catalytic degradation ability when the GO content is 6.25 wt.%.Cu doping can significantly improve the catalytic performance of the Fe3O4/GO nanocomposites,especially Fe2.925Cu0.075O4/GO nanocomposites.Under the same experimental conditions,the degradation rate of p-NP for the Fe2.925Cu0.075O4/GO catalyst is 97.8%in 20 min,while that of the Fe3O4/GO catalyst is only 57.9%.Under the optimal reaction conditions,the p-NP conversion rate and COD removal rate of the Fe2.925Cu0.075O4/GO nanocomposites reach to 98.4%and 74.7%,respectively,and the corresponding H2O2 decomposition rate is about 96.7%.After four recycles,the p-NP removal rate is still as high as 96.0%.(2)The GA and GMA were prepared by combining hydrothermal chemical reduction with freeze-drying.The effects of temperature,pH,adsorbent dosage and other conditions on the adsorption of methyl orange(MO),pump oil and benzene were studied.Under the optimal experimental conditions,the maximum adsorption capacity of GA for MO can reach 160.9 mg/g,the adsorption capacity of GMA(GO:MWCNTs=5:1)for vacuum pump oil and benzene reach toabout 84.9 g/g and 83.4 g/g,respectively.