Reasearch On Electrochemical Degradation Of Tipical Pyrazolones Pharmaceutical Compounds

As development of society and standard of living, environment pollution is increasingly serious. As a supercoutry on pharmaceutical production and consumption, pharmaceutical waste water pollution is prominent. Pyrazoles is one of non-steroridal anti-inflammatory drugs, and was used widely, and diclofenac sodium and aminopyrine are typical pyrazoles. Electrochemical oxidation on pharmaceutical degradation is an effect and edge way on pharmaceutical waste water treatment. In this paper, optimal experiments were conducted on electrochemical oxidation of diclofenac sodium and aminopyrine with un-doped electrode. Optimized condition on degradation of 1000mg/L diclofenac sodium was that 30 mA/cm2 current density,0.1 mol/L electrolyte, pH=7. Optimized condition on degradation of 100mg/L aminopyrine was that initial concentration,20 mA/cm current density,0.1 mol/L electrolyte, pH=3. Intermediates in degradation process of diclofenac sodium and aminopyrine were detected in this paper by GC/MS and IC. Possible pathways of degradation on diclofenac and aminopyrine were proposed depended on intermediates deteceted.Er, Sm, Eu doped PbO2 were prepared in this paper. Compared with un-doped electrode on degradation of diclofenac sodium and aminopyrine, optimized molar ratios of Er, Sm, Eu doped in electrode were determined, and they were 2%、0.5%　and 4%, respectively. Removal efficiency increased by 20.86%　and 3.81%　on degradation of diclofenac sodium and aminopyrine, respectively, with 2%Er doped electrode, compared with un-doped electrode.4%Eu-doped electrode had great positive effect on removal of diclofenac sodium, and removal rates were increased by 21.23% and 9.40%, compared with that of un-doped electrode. And 0.5%　Sm-doped electrode had positive influence only on degradation of diclofenac sodium, while had no positive influence on degradation of aminopyrine.Processing parameters were investigated in electrochemical oxidation system of diclofenac sodium simulated wastewater with 4%　Eu-doped electrode, and result indicated that it was not conductive to the degradation of diclofenac sodium under alkaline condition, and diclofenac dodium concentration and COD removal rate was the highest when pH value was 7, and removal of diclofenac sodium was decreased with initial concentration increased, and was increased with current density increased. Processing parameters were investigated in electrochemical oxidation system of aminopyrine simulated wastewater with 2%　Er-doped electrode, and the optimized parameters were that amidopyrine removal were reduced under both strong acid and strong alkali condition. Initial amidopryrine concentration had little impact on amidopyrine removal when initial amidopryrine concentration was less than 100 mg/L, while, COD removal was decreased with initial amidopryrine increased. Removal of amidopryrine concentration and COD was increased with current density increased.SEM, XRD, CV were conducted on different electrode materials. SEM images on 100 magnified showed that Er, Sm, Eu doping changed morphology of electrode surface, and electrode surface was covered by concavo-convex crystal structure. After Er and Sm were doped, irregular prismatic crystals were generated on electrode surface, and after Eu was doped, elongated ellipsoid crystals were generated on electrode surface. XRD indicated that β-PbO2 peak appeared on XRD curve of electrode surface. Compared with that of XRD curve on un-doped PbO2 electrode, β-PbO2 peak of XRD curve on Er, Sm doped electrode was strengthened. This indicated that Er, Sm doping improved the degree of crystallinity, and this was beneficial on electrode lifetime. Compared with that of un-doped electrode, crystal diameter was enlarged afer Er and Eu doped, and this was positive to expand specific surface area and active site of electrode surface. CV showed that Er, Sm, Er doping strengthen the oxidation peak of CV curve, and improved the catalytic oxidation activity of electrode, while, Er doping decreased the oxygen evolution potential. Er, Sm doped electrodes had amost the same oxygen evolution potential. This indicated that Er, Sm doping had no efficiency on oxygen evolution of electrode.