Research On Catalytic Ozonation Of Sewage Containing Polymer By Amorphous Al₂O₃/Substrate

Oilfield sewage containing polymer is characterized by high viscosity,strong emulsification and hard separation between oil and water,so that reducing viscosity is the key link to improve oil-water separation effect.In this work,the prepared catalysts are made and used to degradate polyacrylamide?HPAM?in sewage during catalytic ozonation,which not only improved the removal rate of HPAM,but also greatly increased the viscosity reduction rate.In this work,alumina sol is synthesised by sol-gel method,then the aluminum sol is loaded onto the pretreated substrate carrier by directly dipping method.Amorphous Al2O3/substrate is used catalytic ozonation sewage containing polymer.Factors in the process of catalyst preparation are optimized,and its structure and morphology are analyzed and characterized.Futhermore,catalyst ozonation conditions are optimized and the mechanism of HPAM oxidation is investigated.The optimum conditions for preparation were as follows:dosage of sucrose is 20.0g/L,the impregnation time is 30 min,and the calcination temperature is 600?.Catalyst is characterized by XRD,SEM and BET,which indecate that it is amorphous Al₂O₃ on the catalyst surface with 372.36 m²/g surface area,and the amorphous Al₂O₃ presents uniform lamellar structure.Results of amorphous Al₂O₃/substrate catalytic ozonation simulated sewage containing polymer show that HPAM removal rate can reach 44.3%;viscosity reduction rate can reach80.1%,when the concentration of 1000mg/L wastewater,pH 7.5,dosage of catalyst 30%,ozone flow rate 0.08m³/h.20.8%and 27.1%respectively higher than that of ozonation alone.The results show that the amorphous Al2O3/substrate presents a beter catalytic activity of O3for wastewater containing polymer.Under the optimum conditions,the HPAM removal rate and the viscosity reduction rate are 34.5%and 73.3%respectively in the real sewage,and the catalytic effect is obviously observed.HPAM removal rate and viscosity reduction rate are40.1%and 77.8%after catalyst has been used for a long period of time,indicating that this catalyst has good stability.Through the analysis of the mode of HPAM degradation and transformation,it is concluded that the rate and magnitude of the reduced viscosity is significantly higher than those of the concentration of HPAM decreased,the viscosity of the solution and the concentration of HPAM under certain conditions the same change exceeds a certain conditions,the two different variation.Chloride ion concentration can effect catalysis on HPAM degradation.During the experiment of free radical inhibitor tert butyl alcohol,it can get that the mechanism of HPAM oxidation catalyzed by amorphous Al₂O₃/substrate is mainly indirect oxidation.Moreover,the catalytic oxidation of amorphous Al₂O₃/substrate can meet the pseudo first order kinetic equation.