Study On Degradation Of Phenolic Wastewater Produced During Pharmaceuticals Preparation

The wastewater emitted during pharmaceuticals preparation endangers humansurvival environment. And Phenolic wastewater is a kind of toxic, refractory andcommon organic pollutants. In recent years, advanced oxidation processes (AOPs) arepaid more and more attention as new environment-purifying technique. In this paper, weuse phenolic wastewater produced during pharmaceuticals preparation as the typicalorganic pollutant.Combining Fenton oxidation, photocatalytic oxidation,electro-catalytic oxidation and biodegradation to degradate the phenolic wastewater, tomake the treated wastewater reach the national wastewater discharge standards.We focuse on the paracetamol wastewater degradation by the photocatalytictechnology, taking the nano-sized TiO2film as the photocatalyst. And our team gainedthe the inventive patent of the method to prepare nano-sized TiO2film.We also focuseon the quizalofop-p-ethyl wastewater degradation by Electro-Catalytic Oxidation,taking the composite Ti/SnO2-Sb2O5/PbO2electrode as anode. Xray diffraction andelectronic microscope were used to test the crystalline type, morphology of the TiO2powder, TiO2film and the combination electrode.The main components of the twokinds of wastewater before and after degradation were researched by high performanceliquid chromatography (HPLC) and infrared spectroscopy.And we researched thereaction kinetics and reaction activation energy of the quizalofop-p-ethyl wastewaterdegradation by Electro-Catalytic Oxidation.In this paper, Fenton oxidation process was used for the treatment ofhigh-concentration paracetamol wastewater. The optimal experimental conditions ofthe Fenton oxidation process is as follows: reaction time is3hours, The PH value ofwastewater is4.0, FeSO4·7H2O dosage is0.10mol/L, H2O（230%）dosage is0.55mol/L.Anatase-TiO2powder were prepared by sol-gel method, and the nano-TiO2film wasprepared by natural extension method. With300W high pressure mercury lamp aslight source, nano-TiO2film as photocatalyst, the photocatalysis degradation ofparacetamol wastewater after Fenton oxidation process is conducted. The optimalexperimental conditions of paracetamol degradation by nano-TiO2film photocatalyticoxidation is as follows: illumination time is4hours, H2O2（30%）dosage is0.0441/L,illumination distance is20cm. The COD dropped to36mg/L from18979mg/Lwith theaction of biodegradation finally. Ti/SnO2-Sb2O5/PbO2electrode was synthesized by Coating, Thermal decompositionand Electrolysis. With self-made Ti/SnO2-Sb2O5/PbO2electrode as anode， thewastewater degradation by Electro-Catalytic Oxidation was studied. We got theoptimal experimental conditions of the Electro-Catalytic Oxidation process is asfollows: electrolytic time is4.0hours, current density is0.033A/cm2, pH is7.0,distances between electrodes are0.50cm, Na2SO4concentration is0.090mol·L–1.Thecomparison experiment of Electro-Catalytic Oxidation process withTi/SnO2-Sb2O5/PbO2electrode, low carbon steel electrode, titanium sheet electrode asanode respectively was studied. The experiment results show that Ti/SnO2-Sb2O5/PbO2electrode has better electro-catalytic property than low carbon steel electrode andtitanium electrode, and Ti/SnO2-Sb2O5/PbO2electrode has excellent stability andservice life.The results of anode polarization curve test show that Ti/SnO2-Sb2O5/PbO2electrode has the highest oxygen evolution potential. Kinetics study of theElectro-Catalytic Oxidation reactions of quizalofop-p-ethyl wastewater degradationshow that it followed a pseudo-first order kinetics. The COD of quizalofop-p-ethylwastewater dropped to60mg/L from16508mg/L by Fenton oxidation, photocatalyticoxidation and electro-catalytic oxidation.