Influence of temperature on the electrosorption of ions from aqueous solutions using mesoporous carbon materials

• Capacitive deionization (CDI) rates are greater at higher temperatures.
• Ion competition in mixtures of ions is more obvious at higher temperatures.
• CDI of produced water should be performed before the water is cooled down.

Based on the electrosorption of ions by charged electrodes, the capacitive deionization method was considered for ion removal from saline water using mesoporous carbon electrodes. Mesoporous carbon was synthesized via a self-assembly method, with a narrow pore size distribution in the range of 6–10 nm. It was found that the rates of ion sorption and release by mesoporous carbon electrodes increase with an increase in the temperature of the solution. A drift in the conductivity was observed during electrosorption of Instant Ocean solutions, which may be explained as the result of competition between ions of different valence and size. The diffusion coefficient of ions during electrosorption was evaluated as a function of temperature, and a transport model coupled with an electrical-double-layer model was employed to calculate the mass of salt adsorbed by the electrodes. The calculated cumulative mass of salt captured in the electrical double layers of the electrodes was compared to the experimental data at different temperatures.

Greater deionization rates of saline water are observed at higher temperatures during electrosorption with mesoporous carbon electrodes.Figure optionsDownload as PowerPoint slide