Scientific and engineering aspects of potential applications of post-consumer (waste) expanded polystyrene : A review

Over the past two decades, the production of expanded polystyrene (in India it is known as thermocol) has increased drastically due to its versatile applications. Consequently, the accumulation of post-cosumer expanded polystyrene (EPS) in the environment has also increased alarmingly. Proper disposal and reuse of waste thermocol has become a serious global concern. In this work, a critical review has been made on various options available for the applications of waste thermocol with a focus on their process chemistry, process parameters, product yields etc. The present manuscript deals with the potential uses of waste thermocol for various applications such as to obtain value added chemicals, to use as an aggregate material in construction field, to prepare composite and porous carbon materials, and an adhesive material. From the in-depth literature analysis, it is observed that the conversion of expanded polystyrene (EPS), and the yield of liquid products mainly depends on degradation temperature, degradation duration, type of catalyst, and catalyst loading. More than 90 % EPS conversion to obtain liquid products could be achieved at a temperature range of 400-500 degrees C. Waste thermocol can be used in construction field to improve setting times, slump value, and water absorption capacity of concrete mixtures. In many studies, a detrimental effect of EPS on compressive strength of concrete mass has been reported. A waste thermocol can also be used to prepare porous carbon with high BET surface area (900-2700 m(2)/g), and high pore volume (1.2-4.2 cm(3)/g). Further, preparation of cost-effective adhesive from thermocol material has also been addressed in the manuscript. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.