SEPARATION AND PURIFICATION TECHNOLOGY, v.330, pp.125438
Abstract
Sulfur dioxide emissions should be and have been regulated due to adverse effects on the environment, and purification of carbon dioxide from low-concentration sources requires energy-intensive steps. Here, we propose incorporating a NaOH-based absorbent with high pH, in which the two gases are simultaneously absorbed, into an electrochemical system that contributes to: (1) mineralizing sulfur dioxide into sulfate; (2) purifying carbon dioxide; and (3) producing hydrogen. Our electrolysis involves primarily anodic sulfite oxidation, and the hydroxide-consuming (proton-generating) sulfite oxidation coupled with cathodic hydrogen evolution allows to generate CO2 with > 85 % purity from an acidifying anodic chamber, and hydrogen evolution from a cathodic chamber with Faradaic efficiency close to 100 %, all at lower energy cost than water electrolysis. This proof-of-concept study demonstrates the feasibility of our functional electrochemical system as a sustainable solution for air pollution control, carbon neutrality, and energy production.