The Role of Zinc(II) in the Absorption–Desorption of CO2 by Aqueous NH3, a Potentially Cost-Effective Method for CO2 Capture and Recycling
✍ Scribed by Fabrizio Mani; Maurizio Peruzzini; Francesco Barzagli
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2008
- Tongue
- English
- Weight
- 292 KB
- Volume
- 1
- Category
- Article
- ISSN
- 1864-5631
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✦ Synopsis
Abstract
The absorption of CO~2~ by aqueous NH~3~ solutions has been investigated at atmospheric pressure and 0 °C. The CO~2~ absorption is fast and occurs with high efficiency (88–99 %). The maximum CO~2~‐removal efficiency increases slightly with the NH~3~ concentration. Addition of zinc(II) salts (as chloride, nitrate or sulfate) to the NH~3~ absorbent solution increases the overall CO~2~‐absorption capacity without appreciably affecting the removal efficiency. Stripping of pure CO~2~ from HCO~3~^−^ solutions is achieved by adding the calculated amount of Zn^II^ salts, which under ambient conditions lead to rapid release of about 30–35 % of the initially captured CO~2~. At the same time, about 65–70 % of the captured CO~2~ is transformed into solid basic zinc carbonates. The recovery of these valuable solid products and the release of only 1/3 of free CO~2~ at room temperature and pressure reduces the cost of the overall process of CO~2~ capture, making it a potentially attractive method for CO~2~ capture on a larger scale.