CO 2 Capture from Flue Gas Using an Electrochemically Reversible Hydroquinone/Quinone Solution

作者：Chuanliang Huang, Changjun Liu, Kejing Wu, Hairong Yue, Siyang Tang, Houfang Lu, Bin Liang · 发表于：Energy & Fuels · 年份：2019 · DOI：10.1021/acs.energyfuels.8b04419 · 被引用次数：76 · 研究领域：Carbon Dioxide Capture Technologies、Chemical Looping and Thermochemical Processes、CO2 Reduction Techniques and Catalysts

Electrochemical methods are potentially an energy-saving way to capture CO 2 from flue gas. Unlike the regeneration of amine through high-temperature thermal distillation in commercial CO 2 absorption processes, the CO 2 absorption solution is regenerated by electrolysis at a low temperature. In this work, tiron (disodium 4,5-dihydroxy-1,3-benzenedisulfonate, QH 2 ) was employed as a pH mediator because its redox reactions can change the pH of the solution. Na 2 Q, which was prepared by QH 2 and NaOH in a molar ratio of 1:2, was used to capture CO 2 because of its alkalinity. Then, CO 2 was desorbed by the oxidation of QH – and QH 2 formed in the CO 2 -rich aqueous solution to quinone (Q) to release protons, and the alkalinity was recovered by the reduction of Q to the quinone dianion (Q 2– ). The redox performance of Na 2 Q in aqueous solution was investigated using cyclic voltammetry, and the CO 2 capacity of Na 2 Q solutions at different concentrations (0.1–0.7 M) was measured. The results show that the redox behavior of Na 2 Q was reversible in the neutral or weakly alkaline solutions. However, the reduction of Q to Q 2– by electrolysis was difficult in a high pH solution. During adsorption, the Na 2 Q solution absorbed CO 2 at a molar ratio of about 1:1 (CO 2 /Q 2– ≈ 1). The CO 2 -saturated Na 2 Q solution was electrolyzed in the anode zone under a constant current. The CO 2 desorption rate reached 100%, and Q 2–, QH –, and QH 2 were oxidized to give Q. In the cathode zo...