Effective pyrolysis of LDPE plastic waste to fuel using titanium dioxide catalyst

Abstract

The widespread use of plastics has led to increased consumption of fossil fuels and worsened pollution, especially in oceans. Common waste management methods like landfills and incinerators often focus more on convenience than on environmental and economic sustainability. For example, incineration releases harmful gases such as carbon monoxide (CO), carbon dioxide (CO2), ammonia (NH3), nitrous oxide (N2O), and nitrogen oxides (NOX), significantly contributing to greenhouse gas emissions. Burning one ton of waste can produce at least 700 kg of CO2. This study explores the use of Titanium Dioxide (TiO2), derived from minerals like ilmenite, rutile, and anatase, to enhance the pyrolysis process of Low-Density Polyethylene (LDPE) plastic waste. TiO2 helps stabilize heterogeneous catalysts and can improve the efficiency of plastic degradation, reduce the necessary temperatures, and shift the output from more liquid to more gas, with properties similar to commercial gasoline. The research tested different temperatures (300 °C, 350 °C, 400 °C, 450 °C) and catalyst amounts (12.5 g, 25 g, 37.5 g) to transform LDPE waste into liquid fuel. The best results were achieved at 350 °C with 37.5 g of catalyst, producing a fuel with a density of 0.7660 g/ml, viscosity of 1.04 mm2/s, calorific value of 36.1698 MJ/kg, and a flash point of 34 °C. Gas Chromatography-Mass Spectrometry (GC-MS) analysis showed that the fuel consisted of 49.41% gasoline, 10.56% kerosene-diesel, and 40.03% fatty acids. The findings indicate that using TiO2 as a catalyst in pyrolysis not only serves as a practical alternative to traditional waste management methods but also supports a more sustainable and economically beneficial approach to recycling plastic waste into usable fuel similar to gasoline. This method could significantly reduce the environmental impact of plastic waste and support economic development through innovative recycling technologies.