CO2 Fixation by Membrane Separated NaCl Electrolysis

Abstract

Atmospheric concentrations of carbon dioxide (CO2), a major cause of global warming, have been rising due to industrial development. Carbon capture and storage (CCS), which is regarded as the most effective way to reduce such atmospheric CO2 concentrations, has several environmental and technical disadvantages. Carbon capture and utilization (CCU), which has been introduced to cover such disadvantages, makes it possible to capture CO2, recycling byproducts as resources. However, CCU also requires large amounts of energy in order to induce reactions. Among existing CCU technologies, the process for converting CO2 into CaCO3 requires high temperature and high pressure as reaction conditions. This study proposes a method to fixate CaCO3 stably by using relatively less energy than existing methods. After forming NaOH absorbent solution through electrolysis of NaCl in seawater, CaCO3 was precipitated at room temperature and pressure. Following the experiment, the resulting product CaCO3 was analyzed with Fourier transform infrared spectroscopy (FT-IR); field emission scanning electron microscopy (FE-SEM) image and X-ray diffraction (XRD) patterns were also analyzed. The results showed that the CaCO3 crystal product was high-purity calcite. The study shows a successful method for fixating CO2 by reducing carbon dioxide released into the atmosphere while forming high-purity CaCO3. OPEN ACCESSEnergies 2015, 8 8705

Comparison of Two Processes Forming CaCO3 Precipitates by Electrolysis

“…Therefore, it is possible to minimize environmental problems caused by waste liquor formed in the process. In addition, natural CaCO 3 formation generally requires long reaction time, as stated in the previous study [15]. On the contrary, both processes we have proposed can reduce the reaction time to form CaCO 3 .…”

“…Each of the units is the same as those used before [15]. The anode (carbon) is located in the center of a round ceramic membrane.…”

“…Depending on 1-4 A of current intensity, electrolysis of NaCl solution was required to react for 10-15 min at 25 °C and 1 bar, and voltage was about 8-24 V. Characterization of the product was reported in our earlier paper [15], and chemical reaction of each step was summarized as follows:…”

“…Our process does not extract oxides and hydroxides from rocks, but uses electrolysis at room pressure and room temperature to obtain hydroxides. More specifically, in our previous report [15], a calcium carbonation process using NaCl solution was introduced. The entire process is divided into three steps: electrolysis of NaCl (sodium hydroxide formation), reaction with CO 2 (sodium bicarbonate formation), and carbonation (generation of calcium carbonate).…”

Simultaneous Sodium Hydroxide Production by Membrane Electrolysis and Carbon Dioxide Capture

“…Park et al also investigated CO 2 fixation by the production of calcium carbonate (CaCO 3 ), after formation of NaOH absorbent through electrolysis of NaCl. Moreover, the solution produced after mineralization can be recycled as a feed solution for the repeated electrolysis to produce NaOH . Mehmood et al designed a novel continuous‐flow electrochemical cell to reduce the energy consumption of the NaCl electrolysis for the production of NaOH which could be utilized for CO 2 sequestration as forms of carbonate minerals.…”