Waste is a Misplayed Resource: Synthesis of Zeolites from Fly Ash for CO2 Capture

Abstract

Fly ash is a kind of industrial waste and large amount of fly ash is produced by power plants throughout the world every year. It is a worldwide concern for disposal of fly ash and converse them into useful products instead of burying them to landfills. Zeolite 13X, a benchmark adsorbent for CO2 capture has been successfully synthesized from solid waste fly ash by a hydrothermal treatment without adding any extra silica or alumina sources. Actually, CO2 is believed to be the primary cause to the greenhouse effect, and a large portion of the CO2 in the atmosphere is from the burning of fossil fuels. CO2 capture from flue gases has been considered as a key measure to reduce this effect in the short term. The prepared zeolite 13X was characterized by X-ray powder diffraction, N2-adsorption-desorption measurements, X-ray fluorescence and scanning electron microscopy. The CO2 adsorption performance of the zeolite 13X was examined by using thermogravimetric analysis. The zeolite 13X showed a high BET surface area of 643 m2/g with a microspore volume of 0.35 cm3/g, and gave high CO2 adsorption capacity (223 mg/g) at 25°C and normal atmosphere. Meanwhile, the prepared zeolite 13X showed stable CO2 adsorption/desorption regenerability. The results indicate that the zeolite 13X synthesized by this environmentally friendly and cost effective method has potential application for low temperature CO2 capture in terms of its outstanding features such as high capture capacity, fast sorption/desorption rate, infinite regenerability and cost-effective.