Research On Graphene Aerogel Materials For Oil Absorption And Air Purification

Graphene aerogel(GA)with high porosity and low density,which assembles from graphene sheets through the Van der waals forces and has a wide application in environment and energy field.In this thesis,we mainly focus on the preparation,modification of the GA as well as functioning the GA as a high-performance photocatalyst.Firstly,the thesis has reviewed the development and background of the graphene aerogel minutely from the aspect of synthesis,modification and functionalization.Based on previous researches,research content and scheme of this thesis have elicited naturally.Then,the thesis has systematically studied the influence of L-ascorbic acid(VC),ethylenediamine(EDA),ammonia as well as hydrothermal time and temperature on the GA through the hydrothermal method.And a series of characterizations,such as X-ray diffraction(XRD),Raman,scanning electron microscope(SEM)and transmission electron microscope(TEM)were selected to study the morphology,structure and other properties of the GA.Absorption performance and absorption-extrusion experiment was also implemented to estimate the application of the GA.The GA reduced from VC performs a most outstanding mechanical strength and hydrophobicity,but poor absorption capacity toward organic solvents and oil,whereas the GAs obtained with ammonia and EDA exhibits a opposite situation.After carefully optimizing the hydrothermal reaction time and temperature of these three reducing agents,we concluded that the EDA is a very promising reducing agent for hydrothermal process.Furthermore,in order to enhance the strength of GA reduced by EDA,the carbon nanotube(CNT)was employed as the additive agent to modified the GA.The ultra-light composite aerogel with the density from 6.2～12.8 mg/cm3 was first synthesized by EDA through a one-step hydrothermal redox reaction.Afterwards,a series of characterizations including XRD,SEM,TEM were measured to analyze the influence of the CNT on the morphology,structure as well as other properties.Furthermore,we have optimized the mass ratio of CNT and GO with 3:1 and 7:1,which the aerogel performs excellent absorption capacity of 100-270 times of its own weight towards different organics and oil.And the obtained hybrid aerogel exhibited excellent reusability and mechanical strength compared with the GA which prepared with only GO.Finally,for expanding the application of graphene aerogel,we innovatively fabricated the integrated C3N4/graphene oxide aerogel photocatalyst by a one-step cryodesiccation route.This simple and mild operation itself makes it being carried out in various containers,which largely extends the shape and size of the photocatalyst.The obtained aerogel exhibits both excellent absorption capacity to oil,organic solvents,dyes and enhanced visible-light photocatalytic activity towards degradation of dyes and oxidation of NO in ppb level.Furthermore,a series of characterizations and electrochemistry tests were performed to understand the mechanism behind this high performance of the material.The results demonstrates the GO in the photocatalyst aerogel efficiently enhance the remove of the photoelectron,which could significantly reduce the recombination of photon-generated carriers.Moreover,the contains of oxygen containing functional groups on the photocatalyst also effects the valence band of C3N4.All in all,this thesis has systematically studied the hydrothermal fabrication of GA,modification with CNT as well as functionalization the GA with efficient visible-light photocatalyst.These fundamental studies have provided us much information to better understand the properties of GA both as a oil absorption materials and photocatalyst supporter.