Improving desalination by coupling membrane capacitive deionization with microbial desalination cell

One main obstacle for the development of microbial desalination cell (MDC) is that desalination rate decreases fast when salt concentration in the cell becomes low. To cover this shortage while using less energy to fulfill complete desalination, membrane capacitive deionization (MCDI) was used in this research as the downstream desalination process to further desalinate 1g/L salt water. Single MDC, two MDCs in series and in parallel were used as the power supply to drive the MCDI, and the parallel-configuration system gave the best ECA of 264.8μmol/g, which was a 59% increase compared to that of driven by the potentiostat with the same operational voltage. The desalination rate of the MCDI was as high as 3.7mg/h in one working cycle. MCDI proved to be an effective technology to combine with MDC for complete salt removal. •MCDI showed a good desalination performance for 1g/L salt water when driven by MDCs.•Parallel connection of two MDCs to drive MCDI gave better salt removal effect.•A MDC driven MDC–MCDI process was developed to treat 10g/L salt water.•A maximum ECA of 264.8μmol/g and desalination rate of 3.7mg/h were achieved.