Adsorption,Extraction And Catalytic Degradation Of Pollutants In Water By Graphene Aerogels

After the discovery of graphene,the modification and application of graphene has flourished.Graphene aerogel(GA),as a three-dimensional structure of graphene material,has gained wide attention.(1)We successfully prepared amphiphilic(hydrophilic and lipophilic)tunable,compressible and self-recoverable graphene aerogels by cross-linked polyvinyl alcohol(PVA)and graphene oxide(GO).It was used to adsorb four kinds of dyes with different hydrophilic or hydrophobic properties.Adjustable amphiphilicity is achieved by varying the ratio of PVA/GA.Due to the cross-linking effect of PVA,GA exhibits good compressibility and self-recoverability.Based on these special properties,GA can expel the eluent completely during the elution process,allowing a rapid desorption and recycling.The results show that this amphiphilic,compressible and elastic GA,as an adsorbent,is very suitable for the treatment of dye wastewater.Its simple synthesis,low cost,non-toxic,easy to use,recyclable and high adsorption capacity give it great potential in large-scale industrial processes.(2)The amphiphilic,compressible,and self-recoverable GA was applied as sorbent in the in-syringe extraction to extract two pesticides,carbaryl and ligulon,from water samples.Due to the cross-linking of PVA,GA exhibited compressibility and self-recoverability,which made it suitable for the in-syringe extraction operation.These properties also enhanced the recyclability and the usage life of it.Meanwhile,it exhibited a specific selectivity for aromatic substances.Thus,GA is idea sorbent for pesticides with aromatic structures.After extraction,the final extract was analyzed by high performance liquid chromatography(HPLC)with a UV detector.The results show that the method can effectively enrich the pesticides.The method was successfully applied for the detection of river water samples.The simple in-syringe extraction procedure in combination with HPLC-UV analysis was demonstrated to be efficient,fast and convenient.(3)ATO/GA bifunctional materials were synthesized by loading nanometer Antimony Doped Tin Oxide(ATO)on the surface of GA,and applied to the adsorption/photocatalytic degradation of brilliant yellow.Firstly,a novel graphene aerogel was prepared by hydrothermal synthesis using ethylenediamine(EDA)as a crosslinking agent and a reducing agent.Thereafter,the ATO nanoparticles are directly dispersed in a solution of EDA,and the ATO is naturally supported on the graphene sheets during EDA crosslinking and reduction of GO.It was proved by SEM,XPS,XRD and FT-IR that ATO was successfully loaded on the surface of ATO.Through the actual adsorption catalysis study of the composite,we found that the combination of carbon architecture and photocatalyst ATO has a significant synergistic effect.Under the synergistic effect of EGA and ATO,the adsorption/catalytic bifunctional material can effectively remove brilliant yellow,achieving 96.5% removal rate at 100 min and 99.1% removal rate at 120 min.