CO<inf>2</inf> removal using alkaline waste as a solid adsorbent: Challenges and forthcoming directions

Toxic and harmful gas emissions from the cement and power industries are one of the major threats for our mother earth and the entire ecosystem. It's difficult to bring down these gas flue emissions to the stringent norms setup by air pollution control board until and unless power plants and industrial chimneys are equipped with new and efficient control technologies. Moreover, as a result of increased living standard of a common man, construction and demolition (C&D) work in India has been increasing by leaps and bounds. This C&D waste generated during the process is causing huge voluminous burden (around 165–175 tons annually) to the environment if not treated and disposed of properly. Consequently, there is a need to introduce an efficient, cost-effective economical technology which can reduce these wastes and solve the problem of flue gas emissions as well. CO2 sequestration using C&D waste is a groundbreaking idea, and it can reduce the further loads on landfills significantly. CO2 is crucially responsible for global warming, and its concentration has accelerated considerably as a result of urbanization as well as industrialization. Since C&D waste is abundant with calcium hydroxide and silica hydrate, it acts as a prominent source for the formation of stable carbonate products during the sequestration process of CO2. The C&D waste can be modified into a useful solid carbonate after addition of CO2. This innovative technology has smaller carbon footprints and is certainly a boon for waste to wealth conversion.