A study on biofuel produced from cracking of low density poly ethylenes using TiO2/AlSBA-15 nanocatalysts

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The burgeoning concerns over the non-biodegradable plastics wastes could be surpassed either by proper disposal technique or by an effective conversion of the plastic wastes into useful chemicals. Metal oxide; TiO2 and porous; AlSBA-15 catalysts were synthesized and a composite characterized using XRD, BET, N2 adsorption –desorption studies, TPD and SEM techniques. This work was focussed in the catalytic degradation of low density polyethylene over the synthesized catalysts in a fixed bed reactor. A hydrocarbon rich gasoline range of liquid fuel, coke and gas were the expected products from the experiment. The liquid products were analysed using GC MS equipped with J&W Scientific DB-Petro capillary column (100 m × 0.25 mm × 0.5 m). An optimum yield of liquid fuel was obtained with TiO2 catalyst at 1st h of reaction and further the product yield considerably decreased. A marginal increase in % conversion of low density polyethylene into fuel was observed with increasing catalyst: polymer ratio in the presence of TiO2 catalyst till 1:5 ratio. The liquid products contained lower range of hydrocarbons with higher content of active catalyst; while the samples collected at later stage contained heavier components. Mesoporous AlSBA-15 worked comparatively better than TiO2 by converting 89.7% of LDPE into 54.8% combustible liquid products. The catalytic activity of the catalyst followed the order of TiO2/AlSBA-15 (10%) < AlSBA-15 (27) < SiSBA-15 < TiO2. A considerable increase in gasoline fraction from 45.6% to 85.4%, yield of liquid fuel (89.1%) and conversion (98.4%) was observed during cracking in the presence of TiO2/AlSBA-15 catalyst. Plastic liquid fuel produced over the composite catalyst revealed the calorific value of 47.8 MJ/Kg which was higher than the commercial petroleum fuel. Finally, we obtain this biofuel application as mathematical model to evaluate and plot the interaction energy arising from the conjugation of TiO2 - AlSBA-15 nano-catalyst in two possible configuration, linear (conical) and spherical molecules, along the range of the αdistance (z-axis).