Synergistic Mechanism And Influence Mechanism Of Electro-catalytic Heterogenerous Ozonation Of Ibuprofen

The pharmercutical-based pollutant ibuprofen(IBU)was chosen as the goal pollutant to study the degradation efficiency of E-catazone.The synergistic effect of the technology was analyzed to clarify the synergistic mechanism.On this basis,the removal rate of TOC from IBU solution and the yield of free radicals(ROS)were compared under different control conditions.The conclusions were shown as follows:(1)The degradation efficiency of IBU parent and TOC by different oxidation processes was compared.The IBU matrix was completely degraded by E-catazone,electrochemical ozone oxidation and ozone catalytic oxidation within 3,15 and 30 minutes,respectively.The mineralization rates of TOC in solution were 60.1%,41.4%and 24.2%,respectively.The kinetic constants of pseudo-first-order reaction for degradation of IBU matrix by E-catazone were 10 times and 2 times of those of ozone catalytic oxidation and electrocatalytic oxidation,respectively.The synergistic factor was 9.9 when combined with ozone catalytic oxidation and electrocatalytic technology.(2)The decomposition of liquid O3 and the production of H2O2 and ·OH in different oxidation systems were compared.It was found that the decomposition efficiency of E-catazone,electrochemical ozonation and ozone catalytic system were 100.0%,85.8%and 50.0%respectively when the reaction lasted for 30 minutes.By comparing the production of H2O2,·OH and O·-in different systems,the concentration of H2O2 and ·OH in E-catazone system was much higher than that in ozone catalytic oxidation and electrocatalytic technology.The concentration of O2·-increased at the beginning and then decreased.·OH was mainly produced at the cathode in the E-catazone oxidation system by anode-cathode separation experiments.The contribution rates of ·OH,O3,other free radicals and electrocatalysis to the degradation of IBU matrix were 97.0%,1.9%,0.7%and 0.4%,respectively by means of the kinetic analysis.(3)The effects of current intensity,ozone concentration and gas flow rate on the degradation and concentration of IBU matrix,TOC and ·OH by E-catazone technology were studied.The increasing current intensity,ozone concentration and gas flow rate could accelerate the degradation rate of IBU matrix and the mineralization rate of TOC solution by E-catazone technology.When the current increased from 50 mA to 300 mA,the concentration of ·OH increased from 33.07 mg/L to 95.47 mg/L.When ozone dosage increased from 32 mg/L to 81 mg/L,the concentration of ·OH increased from 32.00 mg/L to 84.68 mg/L;and when gas flow rate increased from 0.1 L/min to 0.3 L/min,the concentration of·OH increased from 68.80 mg/L to 127.90 mg/L.(4)The effects of initial pH value,electrolyte type and natural organic matter(NOM)on the degradation of IBU matrix,TOC and the concentration of·OH by E-catazone technology were studied.The results showed the alkaline conditions could increase the degradation rate of E-catazone technology on IBU matrix.Under acidic conditions,the degradation efficiency of IBU matrix was inhibited at the pH 3,7.2 and 11,and the concentration of ·OH E-catazone was 10.70 mg/L,90.43 mg/L and 101.72 mg/L,respectively.Electrolyte also had some influence on E-catazone technology,when electrolyte was Na2SO4,Na2CO3 and NaCl solution,IBU matrix degradation efficiency was inhibited and the removal rates were 100%,55.2%and 87.7%respectively.Therefore,lower concentration of NOM could promote the degradation of IBU,while higher concentration of NOM could inhibit the degradation of IBU.Fig.41,table 4,121 references.