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

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%.