Study On The Degradation Of Pyrene By Fe²⁺ Immobilized On Ceramic Membrane

Polycyclic aromatic hydrocarbons(PAHs)are commonly known persistent organic pollutants,with teratogenic,carcinogenic and mutagenic"three-causing"effects.In today's fast-developing society,the use of fossil fuels has become increasingly frequent,making the pollution of PAHs in water and soil more and more severe.As an advanced oxidation technology,Fenton oxidation technology overcomes the drawbacks of general treatment processes.As a highly valuable technology,it has unique advantages and is widely used in the treatment of organic pollutants that are difficult to be degraded in nature.However,in the actual research process,it was discovered that the Fenton reaction has the characteristics of ion loss and can cause secondary pollution.Therefore,seeking an effective degradation method has become an important research trend in recent years.As a product in emerging industries,ceramic membranes have strong chemical properties and heat resistance,lower footprints and high fluxes.They have attracted extensive attention in water treatment and have also been combined with advanced oxidation technologies.It is proved that it can effectively enhance the chemical degradation ability.In order to improve the advantages of Fenton oxidation technology,this article intends to study the removal of PAHs through the combined technology of ceramic membrane and Fenton oxidation process,and screen out the ceramic membrane with excellent performance and load Fe²⁺,and design A set of ceramic membrane Fenton reactor was produced,and on this basis,the Fe²⁺-loaded ceramic membrane was prepared by the silane coupling method,and the ceramic membrane prepared under different conditions was characterized by the instrument,and the optimal conditions for preparing the ceramic membrane were determined;the Fe²⁺-loaded ceramic membrane was used Ceramic membrane combined with H₂O₂reagent to degrade polycyclic aromatic hydrocarbon-pyrene,study the degradation effect of different pyrene concentration,pH,reaction temperature,reaction time,H₂O₂ concentration to degrade PAHs-pyrene,and use GC-MS to detect the degradation process of pyrene.The possible intermediate products,and infer the degradation mechanism and degradation path of pyrene under the ceramic membrane-Fenton process,provide a theoretical basis for the degradation of PAHs in the soil.Based on the above content,this article mainly carried out the following aspects of work:(1)Combining the excellent performance of the ceramic membrane and the performance of the Fenton reagent,a set of ceramic membrane Fenton reaction including water inlet,spiral partition plate,ceramic membrane,outer tube,clear liquid outlet,hydrogen peroxide inlet,concentrated liquid outlet and other configurations is designed.Device.At the same time,three ceramic membranes with different pore diameters and different carriers were selected,and the ceramic membranes were loaded under the same pH and drying time,and the ceramic membranes that could uniformly support Fe²⁺were screened out through SEM,TEM and other instrument characterization methods.The results show that the ceramic membrane with a pore size of 0.14?m and a zirconia/titania coating on?-Al₂O₃ has a good effect on the load performance,which provides good support for subsequent experiments.(2)After screening the ceramic membrane with the best Fe²⁺loading,the optimal process conditions for preparing the ceramic membrane were explored.The effect of different pH,drying time,FeSO₄·7H₂O content on the loading performance of ceramic membranes was studied,combined with SEM,TEM,XRD,XPS,ICP and other characterization methods,the best effect of the ceramic membrane loading Fe²⁺ was discussed.The study surface:When the pH is 5.20,the drying time is 2h,and the content of Fe SO₄·7H₂O is 12.6g,the surface of the ceramic membrane can be evenly covered,and the overall loading effect is good.(3)Taking the refractory polycyclic aromatic hydrocarbon-pyrene as the research object,the degradation effect,degradation intermediate products and degradation path under different conditions were studied:by setting up a single batch and orthogonal experiments,the study found that when the pH is 5.20,the reaction time is 70 min,the reaction temperature is 30?,and the H₂O₂ concentration is 0.80mol·L^-1,the removal rate of pyrene is the largest.At the same time,through the GC-MS method,2,4-dimethylbenzaldehyde,4,5-dihydropyrene,dibutyl phthalate,3,5-di-tert-butylcatechol were detected,and the hydroxyl group was inferred.Free radicals mainly attack the C-C single bonds at positions 9,10,and provide a theoretical basis for subsequent experiments.In a word,this research designed a set of ceramic membrane Fenton reactor and fixed Fe²⁺with silanization reagent,which reduced the loss of iron ions,broadened the application range of pH,and revealed the effect of hydroxyl radicals in the process of Fenton oxidative degradation of pyrene.The mechanism of action provides a theoretical basis for the further application of the ceramic membrane Fenton reactor.