Design and Evaluation of a Nonaqueous FeCl₂/PEG200 System for Industrial NO Capture

Nitric oxide (NO), a major air pollutant from coal-fired power plants, demands an efficient capture for environmental and industrial applications. Ferrous-based absorbents exhibit promising potential for NO capture due to rapid Fe2+-NO complexation. Herein, a novel nonaqueous FeCl2/PEG200 mixture absorbent was designed by employing FeCl2 as the Fe2+ source and PEG200 as the solvent. The FTIR/UV–vis spectrum confirmed Fe2+-NO complex formation and suggested possible reaction mechanisms. Dynamic sorption experiments were systematically conducted to evaluate sorption performance. Kinetic and thermodynamic analyses obtained activation energy, enthalpy change, and entropy change information. Most importantly, a new sorption kinetic model has been established, which can be used to predict the NO sorption capacity at any temperature and partial pressure. Cyclic sorption─desorption testing demonstrated a high desorption efficiency (>91%) and robust cyclic stability over 4 consecutive cycles. This work establishes the FeCl2/PEG200 system as an efficient, reusable, and scalable candidate for industrial NO capture.