Several Graphene-based Adsorption And Photocatalytic Properties And Their Applications In Water Pollution Control

With the rapid development of science and technology,the continuous improvement of human living standards and the environment on which we live is facing a great threat.All water,air and soil have suffered serious damage.Water is the source of life and water pollution directly endangers human health and even survival.It is urgent to control water pollution.Polluted water contains a large number of heavy metal ions,anions and organic pollutants.Adsorption and photocatalysis are convenient and effective treating methods.Graphene has become a good carrier of adsorbents and photocatalysts due to its unique physical and chemical properties.In face of a variety of pollutants,we need to constantly develop targeted graphene functional materials to be used in different pollutant treatment.The main content of this paper is to prepare environmental functional composites based on graphene oxide and to study their performance in pollutant removal.The details as follows:1.A nanocomposite of(Zr O2-Al2O3)/GO was successfully synthesized by a facile sonochemical method.The unique atmosphere created by sonochemistry in the preparation process endows special network to(Zr O2-Al2O3)/GO nanocomposite,which produce larger surface area(42.84 m2/g)and better distribution of metal oxides nanoparticles(14.38 nm)as compared with the same composite prepared by coprecipitation method.The as-synthesized(Zr O2-Al2O3)/GO exhibits the maximum fluoride adsorption capacity of 124.4 mg/L,and the adsorption ability of 13.80 mg/L when F-equilibrium concentration is 1 mg/L,which are both higher than most of the previously reported delfuoridataion adsorbents,indicating it is among the top adsorbents.The real drinking water contaminated by F-was treated by(Zr O2-Al2O3)/GO in a mobile adsorption manner,and the results indicate that the adsorbent can remove a large amount of fluoride from real drinking water to meet the WHO limit,which exhibits the high potential of its practical application.Based on the experimental analysis,the origin of the high defluridation performance and the adsorption mechanism were discussed in details.Due to the facile preparation,easy operation and high performance,the adsorbent and the related sonochemical method are considered to be significant to develop highly effective adsorbents.2.A nanocomposite of Mn3O4/3D r GO was successfully synthesized by a hydrothermal reaction of graphene oxide and manganese oxide on the basis of facile sonochemical method.The results showed that the maximum ciprofloxacin adsorption capacity of Mn3O4/3D r GO composite was 76.09 mg/g at 25? and the adsorption conformed to Langmuir isothermal model.The adsorption equilibrium of ciprofloxacin on Mn3O4/3D r GO composites reached at 12 h and the adsorption kinetics accorded with the pseudosecond-order kinetics equation.Both intraparticle diffusion and external diffusion may exist in the adsorption process to control the adsorption rate.In addition,the adsorption process was mild and could be carried out at 6.1<p H<8.7.It has good anti-interference ability and regeneration ability and can still have 62.3% adsorption effect after four cycles.Finally,based on the experimental data and XPS,the adsorption mechanism of Mn3O4/3D r GO on ciprofloxacin was analyzed in detail.3.A nanocomposite of Bi/Bi OBr/r GO was successfully synthesized by a hydrothermal reaction of graphene oxide and Bi OBr on the basis of facile sonochemical method.The results showed that Bi/Bi OBr/r GO had good adsorption and photocatalytic degradation properties for tetracycline.Under the synergistic action of adsorption and photocatalysis,tetracycline can be rapidly mineralized and completely removed within 20 minutes.Through mobile phase experiments,it is found that Bi/Bi OBr/r GO can remove tetracycline continuously and efficiently for 10 hours,then the removal slowly decreases,and eventually reaches equilibrium at 38 hours(the removal rate is about 40%).Bi Bi Bi OBr/r GO has strong regeneration performance,can be well cycled 5 times without any washing and the removal rate of the fifth time is still as high as 90%.Based on the above research,Bi/Bi OBr/r GO will be beneficial to practical treatment.Based on the experiments of liquid chromatography-mass spectrometry,capture experiment and Mott-Schottky curve,the degradation pathway and photocatalytic degradation mechanism of tetracycline by Bi/Bi OBr/r GO were analyzed in detail.