Charcteristics Of Organic Dyes Degradation By Adsorption And Photocatalysis Of Reduced Grapheme Oxide Based Aerogel

How to solve the problem of environmental pollution in the face of the world energy shortage has become a hot research field.Adsorption and visible light catalysis have attracted the attention of many researchers due to the advantages of simple process,easy operation and low cost.Carbon nitride in graphite phase(g-C3N4)and reduced graphene oxide aerogel(rGOA)are two new functional materials that have become a hot research topic.Based on the advantages and disadvantages of the two materials,this paper conducts a three-aspect study:(1)rGOA with macroscopic three-dimensional(3D)porous frame structure was prepared using GO as precursor by reduction self-assembly method.The samples were characterized by SEM,HRTEM,XRD,XPS5 BET and other means,indicating that rGOA has a three-dimensional reticulated mesoporous structure,with a specific surface area of 294 m2·g-1.Because rGOA is a porous macrostructure with an ?-? conjugate,and most dyes in the environment contain ?-? bond structures,it is easy to be adsorbed by rGOA.The maximum adsorption amount of rGOA on RhB dye reached 304 mg·g-1 and the adsorption process was in line with the Freundlich adsorption equilibrium model.(2)Mesoporous carbon nitride(MCN)was prepared by free template method with melamine as precursor.Then MCN was mixed with GO and the composite aerogel was prepared by reduction self-assembly method.The composite aerogels were characterized by various characterization methods,and the results showed that the mixed aerogels were successfully combined.The specific surface area of MCN/rGOA complex increased from 18 m2·g-1 to 149 m2·g-1.The composite aerogel with the optimal ratio of MCN/rGOA(MCN:GO=3:9)had the highest adsorption rate of 73.7%on RhB(20 mg·L-1,100 mL)within 80 minutes,and the total effect of adsorption and visible light catalysis reached 95.2%.At the same time,the material had good stability,and the removal rate was still about 89%after five repeated experiments.The aerogel mixture not only has good adsorption effect,and has a good photocatalytic performance,combined with the various influence factors in the dye wastewater,test the pH in 3 to 7 removal effect is better,cationic to remove smaller,humic acid can lower removal rate and surface active agent when there are a few promote removal,concentration is greater inhibition of removal.(3)Through Gasusion 09 software by using density functional theory(DFT)B3LYP hybrid functional approach,in 6-31G(d,p)basis set level,structure optimization and energy for the RhB molecules is calculated,and then Multiwfn is used to calculate the free radical reaction coefficient of fukui function find RhB molecules vulnerability loci,combined with Liquid Chromatograph Mass Spectrometer(HPLC-Q-TOF-MS/MS)catalytic degradation of RhB intermediate,put forward the corresponding degradation pathway.