Performances And Mechamisms Of GO/nZVI Nanocomposites For Organic Pollutants Removal

Nano-zero-valent iron?nZVI?is the most potential organic pollutant repair material based on its excellent reduction and catalytic properties.However,this promising technology has been hampered by a key technical barrier whereby nZVI materials tend to agglomerate and oxidize due to their high surface energies and inherent magnetic forces.In order to solve this problem,nZVI particles can be immobilized on mechanical support materials.In recent years,the novel two-dimensional nanosheet material graphene has received enormous research attention due to its high surface area,mechanical properties,and exceptional electron transport characteristics.Graphene oxide?GO?,a kind of chemically modified and highly oxidized garaphene material,contains oxygen-containing functional groups which is more applicable for loading nanoparticles.Some studies have used GO as a supporter material to remove pollutants.The aim of this study is to prepare a graphene oxide-iron nanocomposite?GO/nZVI?and evaluate its performance for atrazine removal from aqueous solutions.The mutual interactions between GO and nZVI are determined by characterizing the composition,morphology,and microstructure of GO/nZVI.And the GO/nZVI-activated persulfate coupled with Fenton oxidation process is applied to remove organic pollutant.Some valuable findings are as follows:?1?The performance and mechanisms of GO/nZVI composites for atrazine removal were studied.GO can improve the dispersion and stability of nZVI and increase the amount of nZVI loaded in the folds of GO,resulting in a greater specific surface area,pore volume and more defects structure of GO/nZVI.These structural changes facilitate the interaction between atrazine and increase the removal efficiency of atrazine.Batch experiment results indicate that GO/nZVI can achieve higher atrazine removal efficiency than both pristine nZVI and GO.This is due to the synergetic effects of reduction by nZVI and adsorption by GO.Moreover,GO can accelerate the electron transfer efficiency of nZVI and enhance the interaction between the remaining contaminants and GO/nZVI,thereby improving the dechlorination efficiency of Atrazine.nZVI also increase the adsorption of atrazine onto the surface of GO/nZVI?-?stacking of wrinkles,pore-filling of mesopores,and?-?EDA of GO/nZVI.?2?The performance of GO/nZVI composites activated persulfate coupled with Fenton oxidation for phenol removal was studied.The degradation efficiency of phenol in the GO/nZVI-PS-H₂O₂ system is 1.3 times and 25 times than GO/nZVI-H₂O₂ and GO/nZVI-PS systems respectively,which is ascribe to the acidifying effect of persulfate addition and the reduction of p H value could further finalize phenol degradation independently from initial p H.Both SO₄^·-and·OH contributed to the degradation of phenol in actived perfulfate/H₂O₂ systems,while·OH proved the predominant radical in the combined oxidation process.