Carbon dioxide capture by carbon adsorbents derived from waste plastics

Abstract

In the present era, one of the major threats to environment is climate change and the well known and accepted basis for this is greenhouse gas (GHG) emissions. CO2 is the key contributor promoting global warming and subsequently affecting the climate as manifested by frequent occurrence of floods and droughts, progressive rise in temperature and sea levels, heat waves and melting of glaciers. To economically sequester CO2, it is imperative to comprise cost-effective capture for which the adsorption-based post-combustion CO2 capture has been identified as a promising alternative due to its lower energy requirements, cost-effectiveness, and simplicity in use at a broad range of temperatures. However, the main challenge in successfully commercializing adsorption technology is the development of effective and low-cost adsorbents. Further, plastic waste generation is another major problem that is causing a deleterious effect on our environment. It is estimated that approximately 15,000 tonnes of plastic wastes are generated every day in India and polyethylene terephthalate (PET) waste takes around 500-700 years to biodegrade, therefore environmentalists are seriously concerned about its disposal. Literature studies indicate that carbons from PET wastes especially chemically activated ones have immense potential to adsorb CO2 due to generation of micro/meso pores post carbonization. Also, it has been observed that majority of the CO2 capture studies on PET-based adsorbents have been performed thermogravimetrically which is a suitable method for preliminary studies and cannot be implemented on large scale at industry level. Moreover, in this method adsorption is measured on weight gain basis which may involve higher component of error due to adsorption of other gases. Therefore, there is a need to perform CO2 adsorption studies in a packed column which can be scaled up.