Low Voltage Electrochemical Process for Direct Carbon Dioxide Sequestration

Today, alkalinity, in the form of sodium hydroxide (NaOH), is primarily produced from the chlor-alkali process. Alkalinity produced by the chlor-alkali industry is used in a multitude of different processes: pulp and paper products, food and beverage industry, aluminum production, and as a key component in many chemical processes. Additionally, the use of alkalinity to sequester carbon dioxide (CO2) from carbon-intensive power and industrial plants has become an important new topic in recent years. However, there are two severe penalties that come with the chlor-alkali process, namely, high energy consumption and the coproduction of toxic chlorine gas. Here we show two patented novel low-energy electrochemical processes that produce alkalinity and directly sequester carbon dioxide while generating pure streams of sodium bicarbonate (NaHCO3) and hydrochloric acid (HCl) at +0.82 and −0.42 V, theoretically. As a result, the theoretical energy demand for producing alkalinity is reduced by 81% (Process 1) and 137% (Process 2) compared to the chlor-alkali process, chlorine gas production is avoided, carbon dioxide is sequestered, and valuable acid is produced.