Polystyrene (PS) is an integral part of global plastic market and a highly valued thermoplastic. The major applications of PS and expanded PS (EPS) include packaging, construction, appliances and electronics. The global demand for PS and EPS increased from 13 million tons in year 2000 to around 14.9 million tons in 2010; which is expected to further grow to approximately 23.5 million tons by year 2020. However, this increase in usage results in proportional increase in the PS waste, which is non-biodegradable and thus leads to a serious impact on health and environment. Also, disposal of the low density Styrofoam (a popular form of EPS) becomes unmanageable as gets easily littered. PS waste management is a serious concern. PS wastes are usually discarded in dumps and landfills or incinerated.
The desirable solution for PS waste management is the recycling of PS. However, they are quite labour- and/or energy-intensive. According to a 2004 study by California Integrated Waste Management Board, only 0.8% of PS produced is recycled in the USA.
Dr Chandrashekar Sharma and his team have developed a novel and innovative way to recycle PS waste, directly into sub-micron, aligned PS fibers by using extracts from peels of citrus fruits. The citrus peels are generally discarded while processing/using fruit and thus, process developed in this work will also help in managing this agricultural waste. Worldwide, citrus fruits production is more than 31 million tons annually, out of which nearly 50% is waste in form of peel. The process developed to directly recycle waste PS into non-woven fabric using extract from citrus peel waste is clearly an illustration of novel, green, low-energy and cost effective scalable process. Moreover, the fabric obtained is hydrophobic and can selectively absorb oil from water and thus the team has demonstrated its use for oil-water separations leading to applications from day to day household cleaning, waste water treatment, packaging to global requirement of oil spillage remediation.