Ahmad Hallajisani - Caspian Faculty of Engineering, College of Engineering, University of Tehran, P. O. Box: ۱۱۹-۴۳۸۴۱,Rezvanshahr, Iran
Ehsan Ghiasy Nick - Caspian Faculty of Engineering, College of Engineering, University of Tehran, P. O. Box: ۱۱۹-۴۳۸۴۱,Rezvanshahr, Iran
Zahra Yaghoubi Feshki - Caspian Faculty of Engineering, College of Engineering, University of Tehran, P. O. Box: ۱۱۹-۴۳۸۴۱,Rezvanshahr, Iran

In recent years, environment pollution has become one of the most serious challenges around the globe.Since last century, the rate of waste accumulation on landfill has been risen too rapidly. One of the mainreasons of this pollution are plastics, because most of them are not degradable in nature. Between differentpolymers, one of the most useful of them is Polystyrene. PS is a versatile, cheap, and hard polymer. It can beused in kitchen appliances, food packaging, toys, and etc. But most of the P.S manufactured in industries willend up as communal waste, so it can pollute and damage nature. To overcome this problem, recycling of P.Sis suggested. There are several methods to recycle PS into different forms like thermal recycling, chemicalrecycling, mechanical recycling, photodegradation, and etc. In this paper, some these methods will be brieflyreviewed and explained.

Polystyrene, Waste recycling, Chemical recycling, Photodegradation, Mechanical recycling