Preparation Of Functional Graphene Derivatives And Their Application In Environmental Engineering

In recent years,the monitoring and management of the environment has attracted more and more people’s attention.Graphene oxide is a good adsorbent due to its large specific surface area and good stability under acidic and alkaline conditions.In this thesis,the graphene oxide was modified by amino and halogen groups.Four novel graphene derivative materials,GOLA,GOLB,GOLC and GOLF,were prepared,respectively.Adsorption properties of four absorbents for removing heavy metal ions Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ),Cu(Ⅱ)and Ni(Ⅱ)were investigated.GOLH would be employed as a saturable absorber.Its optoelectronic properties were investigated by a Q-switching laser.(1)Preparation of amino-functionalized graphene oxide-like and adsorption of them for heavy metal ions.Amino-functionalized graphene oxide was prepared using anhydrous as functionalizing reagent.They were characterized by FT-IR,EA and XRD.Adsorption properties of three absorbents for removing heavy metal ions Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ),Cu(Ⅱ)and Ni(Ⅱ)were investigated.Highest adsorption capacity of DGO for Pb(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 433.32,304.51,55.50,57.21,98.62 mg/g,respectively.Highest adsorption capacity of GOLH for Pb(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 453,32,310.19,57.89,52.25,116.57 mg/g,respectively.Highest adsorption capacity of GOLA for Pb(II),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 505.80,401.99,83.48,82.29,147.77 mg/g,respectively.Their adsorption isotherm of Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ),Cu(Ⅱ)and Ni(Ⅱ)could be well fitted with the Langmuir adsorption model.Their adsorption kinetics was in accordance with the pseudo-second-order kinetic equation.(2)Preparation of halogen-functionalized graphene oxide-like and adsorption of them for heavy metal ions.Halogen-functionalized graphene oxide was prepared using sodium bromide,sodium chloride and sodium fluoride as functionalizing reagents,respectively.They were characterized by FT-IR,EA and XRD.Adsorption properties of three absorbents for removing heavy metal ions Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ),Cu(Ⅱ)and Ni(Ⅱ)were investigated.Highest adsorption capacity of GOLB for Pb(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 485.06,329.99,70.55,74.25,115.56 mg/g,respectively.Highest adsorption capacity of GOLC for Pb(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 484.32,335.58,74.74,59.33,127.23 mg/g,respectively.Highest adsorption capacity of GOLF for Pb(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Ni(Ⅱ)and Cr(Ⅲ)was 489.32,335.38,75.75,66.06,124.02 mg/g,respectively.Their adsorption isotherm of Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ),Cu(Ⅱ)and Ni(Ⅱ)could be well fitted with the Langmuir adsorption model.Their adsorption kinetics was in accordance with the pseudo-second-order kinetic equation.(3)Preparation of large-size graphene oxide-like with hydroxyl groups and its optoelectronic properties.A new type of graphene oxide-like with hydroxyl groups(GOLH)was synthesized.It was characterized by FT-IR,EA,Raman and DLS.GOLH would be employed as a saturable absorber.Its optoelectronic properties were investigated by a Q-switching laser.A Q-switched pulse laser with the GOLH materials exhibited stable signal intensity and narrow pulse duration.A repetition rate of 71.4 kHz was obtained with pulse duration of 0.8 μs under 6 W of the incident pump power.