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Keywords:

  • polyethylene;
  • degradation;
  • tungstophosphoric acid;
  • impregnation;
  • mesoporous material;
  • catalyst;
  • SBA-15

Abstract

Tungstophosphoric acid (TPA)-containing mesoporous santa barbara amorphous (SBA)-15 materials were synthesized by impregnation of TPA into hydrothermally synthesized SBA-15. TPA was incorporated to the porous framework of silica with different W/Si ratios, using TPA hydrate as the acid source. The synthesized materials had a surface area range of 212–825 m2 g−1, depending on the TPA loading and exhibited Type IV adsorption–desorption isotherms. Energy dispersive spectrometry and X-ray photoelectron spectroscopy (XPS) analyses showed that TPA was successfully penetrated into mesopores of the SBA-15 material. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis of the pyridine adsorbed synthesized materials revealed the existence of Lewis and Brønsted acid sites in the synthesized materials. Their performances were tested in the degradation of polyethylene by thermogravimetric analysis. An increase in TPA content significantly lowered the degradation temperature and activation energy of the polyethylene degradation reaction. In the presence of TPA-incorporated SBA-15 catalyst, activation energy was reduced to approximately half-value of the value found in the absence of the catalyst. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2466–2472, 2012