Styrene recovery from the pyrolysis of polystyrene waste using bentonite and natural zeolite catalyst

Polystyrene is a type of plastic that is widely used in daily life. It is applied for decoration, food packaging, and electronic packaging process. However, the use of polystyrene has become a problem for the environments because its properties are difficult to be degraded by nature. Pyrolysis method can be regarded as one of the environmentally friendly methods for recycling polystyrene waste. This research aims to investigate the effect of bentonite and natural zeolite catalyst on the pyrolysis of polystyrene. The experiment was carried out in a batch process. The pyrolysis process consists of a cylindrical reactor with electrical heater, a condenser, and a liquid product container. About 100 grams of polystyrene material was pyrolysis per batch. Catalysts used in the variation of 0, 10, 15, 20, and 25 of polystyrene. The liquid product was collected in 60 minutes and weighed. The composition of the liquid product was determined by gas chromatography. Polystyrene pyrolysis utilizes bentonite and natural zeolite as the catalyst. It produces benzene, toluene, ethylbenzene, styrene, and isopropyl benzene as the liquid product, and polystyrene residue as a solid product. Among the catalyst studied, bentonite is found to be the most efficient and increase the styrene selectivity (30.28 wt) significantly at a reaction temperature of 400°C in comparison to the natural zeolite catalyst. © 2020 Trans Tech Publications Ltd, Switzerland.