Study On The Graphene-based Carbon Capacity Of Adsorption And Photocatalytic Reduction Of Chromium Hexavalent

In recent years,the problem caused by heavy metal pollution has become more and more serious.For Cr（VI）,as one of the most common heavy metal pollutants,has a very serious harmful effect on human beings and the environment,which has received much attention.In this study,Cr（VI）was used as the target pollutant,metal oxide supported reduction graphene oxide（r GO）composite was used as adsorbent and photocatalyst,and the degradation rule and specific reaction mechanism were investigated in adsorption reduction and photocatalytic reduction respectively.The main research results of this paper are as follows:（1）Znr GOx adsorption reduction of Cr（VI）:via practicing the hydrothermal method,GO and Zn（NO3）2·6H2O are mixed to synthesize some series of Znr GOx materials.A series of characterization（SEM,XRD,FT-IR,Raman,etc.）and experimental results show that Znr GO0.1 composite has the best adsorption performance,the removal rate of Cr（VI）reaches 99%within 3h and the maximum adsorption capacity is 69.887 mg/g.Moreover,the effects of different experimental conditions on Cr（VI）removal were researched,and the optimal operation process was determined.Through isotherm model and kinetic model simulation and material characterization,it can be reported that composite monolayer adsorption,chemisorption chemical adsorption and material surface functional groups are the main reasons leading to Cr（VI）removal.In addition,Znr GO0.1 showed good stability and reusability for Cr（VI）removal.（2）Cur GOx photocatalytic reduction of Cr（VI）:using GO and Cu（NO3）2·6H2O as precursors,a series of composite materials with different doping ratios（Cur GOx）were synthesized by alkaline hydrothermal method and characterized.The results show that Cur GO0.3 composite has the best photocatalytic activity on Cr（VI）（the removal rate reaches 100%）,and the reduction ratio can also reach 95.87%.Meanwhile,the photocatalytic reduction efficiency of Cur GO0.3 composite was investigated under different experimental conditions,and the optimal process parameters were obtained.In addition,coexisting ions and cyclic experiments prove the applicability and stability of Cur GO0.3 composites in practical applications.Finally,the main roles of photogenerated holes（h⁺）,electrons（e）and surface carboxylic acid groups in the photocatalytic reduction of Cr（VI）system were determined by inhibitor experiments and characterization of catalysts before and after reaction.In conclusion,Cur GO0.3proved to be a highly efficient and stable catalyst for the treatment of Cr（VI）in water.