| Benzene is often used as a solvent,is often applied to petroleum,electronics,painting,printing,pesticide,decorative materials,etc.What is more,benzene series has strong volatile,so that The toxic benzene and xylene evaporating into the air.They can harm the human body through the respiratory and skin contact,causing permanent damage to the respiratory tract,blood and liver,benumbing the central nervous system.such as Benzene and benzene and class,carcinogenic polycyclic aromatic hydrocarbons can make the human body carcinogenic.So for the benzene content of governance is of great urgency.Using self-made bubbling reactor,this experiment study Fenton reagent removal of benzene and xylene performance respectively.Based on the typical industry VOCs concentration range,I set the benzene concentration to 100-1000mg/m3,xylene concentration of 500-1200mg/m3.Test own 5 factors influencing:pH,FeSO4 mass concentration,H2O2 volume ratio,benzene/xylene controduction and the reaction time,respectively through the single factor tests and response surface curve method to determine the optimal parameter combination of test.Test the following conlutions:Fenton reagent removal of benzene in the single factor test results show that:when the pH=3,FeSO4 quality concentration=0.79mg/m L,H2O2 volume ratio= 0.79%,t=22s and C=100-200mg/m3,the best benzene removal efficiency can reach 95%.Fenton reagent removal of xylene of single factor test results show that:when the pH=3,FeSO4=0.53mg/mL concentration,H2O2=0.53%,the ratio of volume of t=22s and C=500-700mg/m3,the best removal efficiency of xylene can reach about 85%.With the pH value,FeSO4 mass concentration and H2O2 volume ratio,Removal efficiency increase after first is reduced,the reason is that the existence of the three factors influence the Fe valence and discharge of·OH:when the low pH value,H2O2 is too small,the ratio of volume of FeSO4 mass concentration is too low,the reaction can lead to a lack of Fe2+,and ·OH,so it can't remove a certain amount of benzene/xylene.Increases along with the three factors of variable,·OH quantity more and more,so the removal efficiency increased gradually.With the increased the quantity of three factors,it will lead to excessive Fe2+ into Fe3+,excessive discharge of ·OH,causing the occurrence of adverse events,resulting in a loss of benzene/xylene removal efficiency and the waste of reactants.Fenton reagent removal of benzene/xylene test curves of the response surface method,based on the test result made a three-dimensional stereo image,contour map and data fitting,the fitting of the regression equation is as follows:benzene removal =88.67+9.46A+3.57B+8.78C-1.84AB-3.41AC-1.54BC-16.02A2-1.35B2-6.47C2,xylen e removal efficiency=82.86+8.52A+4.78B+5.57C+2.32AB+1.94AC-2.10BC-21.23A2-10.57B2-16.69C2.Through the analysis,the model fitting was not significant,and significantly said equation fitting is good,the test precision,reliability,accuracy,good fitting regression equation of the principle of testing,it has good adaptability.The dynamics of Fenton reagent removal of benzene and xylene reaction series for the first order reaction kinetics ln?C0/C?=kt.According to the mathematical function of fitting calculation of reaction rate constant,which can calculate the reaction rate equation:r=0.6768[Cbenzene]0.3190,r=1.1721[Cxylene]0.4032.In this experiment,I increase the concentration of reactants,increase the number of effective collisions reactant molecules,the reaction rate to speed up the pH enomenon in the experiment takes concentration and determination of time range,which shows the reaction of benzene and xylene are the speed factor. |
PDF Full Text Request