Study on catalytic pyrolysis of polystyrene over base modified silicon mesoporous molecular sieve

摘要

K2O/Si-MCM-41 molecular sieve was prepared by impregnating Si-MCM-41 with KNO3.The obtained material was characterized by XRD,FT-IR,TEM and N2Ad/De,the results indicated that K2O/Si-MCM-41 was of typical mesoporous structure,and the long-range order of K2O/MCM-41 became poorer with the increase of K2O.The catalytic properties of K2O/Si-MCM-41 were investigated in the pyrolysis of polystyrene(PS).The results were compared with those obtained using CaO,Si-MCM-41 and Al-MCM-41 as catalysts.It was shown that K2O/Si-MCM-41 is of better catalytic activity.The effect of preparing conditions on activity of K2O/Si-MCM-41 was discussed.KNO3 was almost completely decomposed into K2O at optimum calcination temperature of 600°C.Under the optimum conditions of mass percentage of K2O 9%,temperature 400°C,m(catalyst):m(PP)= 0.02 and reaction time 0.5 h,the conversion of PS was 90.53%,the yield of liquid products was 85.67%,and the yield of styrene reached 69.02%.