Preparation And Performance Evaluation Of Hydrophilic Graphene-based Fenton-like Catalyst

With the application of heterogeneous Fenton-like oxidation technology in wastewater treatment,it is very important to develop efficient heterogeneous Fenton-like catalyst.The two-dimensional graphene has excellent physical and chemical properties and can be used as an ideal carrier for heterogeneous Fenton-like catalysts.In this paper,graphene oxide（GO）was prepared from natural flake graphite concentrate by the improved Hummers method,and the intermediate in the preparation process was systematically analyzed to construct the mechanism model for the preparation of GO from natural graphite concentrate.GO was modified with sodium dodecyl benzene sulfonate（SDBS）to obtain hydrophilic sulfonated graphene oxide（SGO）.Using SGO as the carrier material,the heterogeneous Fenton catalyst Fe₃O₄/HG with excellent hydrophilicity and magnetic properties was prepared by in-situ assembly.An azo dye methyl orange（MO）was used as a simulated pollutant to evaluate the reaction efficiency of hydrophilic graphene-based Fenton catalyst and to study the kinetics of the reaction process.XRD,Raman,FT-IR,UV-vis,SEM,TEM,VSM and BET were used to analyze the composition,structure,morphology and hydrophilicity of GO,SGO and Fe₃O₄/HG.The mechanism of GO preparation from natural graphite concentrate is that the H₂O₂/H₂SO₄ pretreatment system oxidizes the graphite edge to increase the graphite edge layer spacing,and then the more oxidized KMn O₄/H₂SO₄ enters the graphite layer to form a large number of oxygen-containing functional groups and expand the graphite layer spacing.At the same time,the sulfonate group was successfully introduced into GO and Fe₃O₄ nanoparticles were assembled in situ on the sulfonated GO surface.Fe₃O₄/HG has a small water contact Angle,a large specific surface area and excellent magnetic properties.The results of degradation efficiency of Fe₃O₄/HG heterogeneous Fenton system showed that the preparation of Fe₃O₄/HG with SGO 10%,synthesis time 4 h and synthesis temperature 85℃had the best Fenton Catalytic oxidation activity.When the initial p H is 3,the concentration of H₂O₂ is 14.535 m M,and the amount of catalyst is1 g/L,the degradation rate of 10 mg/L methyl orange solution in 60 minutes can reach99.6%,and the reaction process belongs to the first-order reaction kinetics.