The catalytic performance for LDPE destruction over aluminum-incorporated mesoporous silicates

The aim of this study was to investigate the aluminum-incorporated mesoporous silicate (Al-MPS) as a thermal catalyst for the destruction of low density polyethylene (LDPE). Various Al-MPS (Si/Al molar ratios = 117.6, 58.8, 39.2 and 29.4) materials were successfully synthesized without any structural damage. With regard to the X-ray diffraction (XRD) pattern, the main peak of 2θ = 64.0 in Al2O3 did not show until the incorporation of Si/Al = 58.8. This result implies the aluminum ions were stably substituted into the silicon site of the mesoporous framework. The hexagonal straight pore size increased to about 8.0 nm in Al (Si/Al = 58.8)-MPS, but then decreased in the range of 3.0-5.0 nm in Al (Si/Al = 29.4)-MPS. In relation to the amount of incorporated aluminum, the Al-MPS absorbed many pyridine molecules, implying the acidities on the external surfaces up to Si/Al = 58.8, but this amount decreased somewhat above a Si/Al ratio of 39.2. The catalytic decomposition of LDPE was enhanced in Al (Si/Al = 58.8)-MPS and particularly, the selectivity to light hydrocarbons below C4 reached 43%.