Experimental Study On Three-dimensional Fenton Treatment Of High Concentration Refractory Organic Wastewater

The high-concentration refractory organic wastewater is characterized by high concentration,high toxicity,and high difficulty in handling,and it has great harm to human health and social environment.Three-dimensional electro-Fenton method is a kind of advanced oxidation method,which has the characteristics of strong oxidizing ability,high current efficiency,less secondary pollution,and has obvious advantages in dealing with high-concentration refractory organic wastewater.In this dissertation,the three-dimensional electro-Fenton method with high catalytic activity cathode,anode and modified graphite particle electrode was used to treat high-concentration refractory organic wastewater.The effects and influencing factors of three-dimensional electro-Fenton method were explored.The effectiveness of the Fenton process and the traditional Fenton process under the optimal reaction conditions was compared.Experimental results show:(1)Among the three anode materials tested,the Sb-doped SnO2/Ti anode has a distinct electrochemical performance advantage over the niobium-coated titanium anode and the Pt anode.The oxygen uptake potential is as high as 1.6V vs.SCE in the degradation of RhB.The CODcr removal rate reached 80.41%,the RhB removal rate reached 88.33%,and the amount of electricity required to remove the unit of mg CODcr was 25.8 mA h.(2)Among the three cathode materials tested,the foamed nickel is more suitable as the cathode of the electro-Fenton than the activated carbon fiber and graphite.The H2O2 is strong,and the degradation of organics is effective and stable.The concentration of H2O2 reaches 110.09 at 120 min electrolysis.Mg·L-1 degraded RhB experimental wastewater under the electro-Fenton reaction conditions with foamed nickel as the cathode.When the reaction time was 120 minutes,the removal rate of CODcr was 57.42%and the removal rate of RhB was 89.56%.(3)After characterization by SEM,EDS and XRD,the particle electrode SC1 was successfully prepared by modifying CeO2 on the surface of graphite,and SC2 was successfully prepared by modifying CeO2 and Fe-Mn oxides on the surface of graphite.The surface of SC1 is covered with more CeO2.The content of Ce on the surface of SC1 is 19.08%.The surface of SC2 covers the Ce02 and Fe-Mn oxides uniformly.The Ce content on the surface of SC2 is 12.67%,the Fe content is 3.51%,and the Mn content is 0.88%.(4)Among the two kinds of particle electrodes prepared,SC2 is the most suitable particle electrode for the three-dimensional electro-Fenton method,and its ability to produce hydrogen peroxide is strong,and the organic degradation efficiency is high.After 120 min of electrolysis of pure water,the concentration of H2O2 reached 186.48 mg·L-1.When the wastewater was degraded,the removal rate of CODcr reached 82.35%and the removal rate of RhB was 89.35%.(5)Three-dimensional electro-Fenton system with Sb doped SnO2/Ti as anode,foamed nickel as cathode,and Ce-Fe-Mn modified graphite as particle electrode.The volume of the reactor is 2L.It is best to treat high-concentration refractory organic wastewater.The reaction conditions were:suspended filler,cell voltage 20V,pH 4.12,Fe2+ dosage 2 mmol/L,particle electrode dosage 36,circulating flow 50 mL·min-1,aeration intensity 0.2 m3·h-1,The amount of hydrogen peroxide added was 1.5 mL·h-1.(6)The three-dimensional electro-Fenton method has obvious advantages compared with the conventional electro-Fenton method and the traditional Fenton method for treating high-concentration refractory organic wastewater,and the current efficiency during the reaction is 34.19%when treating high-concentration refractory organic wastewater.The average electricity-Fenton method increased by 15.25%;the energy consumption was 205.78W·h·(gCODcr)-1,which was 44.59%lower than that of the conventional electro-Fenton method;the effluent CODcr was reduced from 17928 mg·L-1 to 9764 mg·L-1 The removal rate was 20.31%higher than that of the conventional electro-Fenton method,0.56%higher than that of the conventional Fenton method,and the B/C was increased from 0.06 to 0.38,which was 42.1%higher than the conventional electro-Fenton method and 10.5%higher than the conventional Fenton method.It was 4.63,which was 1.52 higher than that of the traditional Fenton method.The Fe2+ dosage was 2 mmol·L-1,which was 50 mmol·L-1 less than the traditional Fenton method.The three-dimensional electro-Fenton process is a pretreatment of wastewater treatment and creates very good water quality conditions for subsequent biochemical treatment.