The Preparation Of Heterogeneous Catalysts And Catalytic Oxidation Of Polyacrylamide

As the promoting of polyacrylamide (PAM) in our tertiary oil recovery industry, more PAM that residues in the environment will have a tremendous potential harm the environment. Thus, How to deal with produced water containing polyacrylamide(PAM) has become a focus of the study. The application of Fenton’s process in wastewater treatment is a widely available and non-toxic element and hydrogen peroxide is easy to handle and the excess decomposes to environmentally safe products. However, it’s reaction conditions require pH3-5and the need of removing iron after the treatment. To solve this problem, heterogeneous catalytic oxidation method has become the new direction of research. Fe2O3/Al2O3as the load-type heterogeneous catalyst was prepared in this paper and used to the degradation of PAM in produced water in the presence of hydrogen peroxide.Preparation Methods have an important influence of catalytic activity. In this paper, the Fe2O3/Al2O3heterogeneous catalysts was prepared by soakage. The effects of concentration of the soaking solution, soaking time, calcination temperature, calcination time, etc were investigated, and the optimal conditions were determined as follows:Fe(NO3)3as the impregnated material and concentration of activity carried was20%, carrier particle size was140-180mesh, soaking temperature was30℃, soaking time was12h, calcination temperature was500℃, calcination time was3h.In order to improve the catalytic activity, the Fe2O3/Al2O3heterogeneous catalysts was prepared by acid dipping and adding trace elements. It was found that using1mol/L acid solution dipping and adding1%of the trace elements Cu modified measures can greatly enhance the catalytic activity.99.4%molecular weight of polyacrylamide was removed after90min in the presence of2.0g/L Fe2O3/Al2O3catalyst,0.6g/L H2O2at pH=7.0and t=60℃.In the paper, The effects of Fe2O3/Al2O3load, H2O2concentration, pH and the reaction temperature on the degradation of polyacrylamide were investigated. The best reaction conditions were determined.86.8%COD of produced water was removed after90min in the presence of2.0g/L Fe2O3/Al2O3catalyst,0.6g/L H2O2, at PH=7.0and t=60℃. The concentration of Iron ion in waste water is only0.08ppm and the catalyst had a long service life. After seven time repeat-used, the catalytic activity has not been reduced.Besides, by studying decomposition of H2O2in the presence of catalyst and effect of scavenger of Hydroxyl radical on the degradation reaction, reaction mechanism of heterogeneous catalytic system was determined.