多级串联膜电容去离子装置的脱盐性能

膜电容去离子(membrane capacitive deionization, MCDI)技术具有的装置简单、易操作、易再生、成本低，无污染、节能等优势，使其成为一种新型的脱盐技术。为了提升MCDI的脱盐性能，将多个装置的进水串联，对每个装置单独加电来探究脱盐率，平均脱盐速率、单位能量脱盐量等指标对多级串联的影响。结果表明，在进水盐质量浓度、水力停留时间、电压等不同操作条件下，二、三级MCDI串联脱盐率都提高了约2、3倍，三级串联较二级串联的脱盐速率提升较小，但具有更高的能耗。综合比较，二级MCDI串联的脱盐性能更优，并获得了最佳的操作条件为1.5 g·L⁻¹，0.375 min，1.2 V。在连续脱盐过程中，多级串联能够连续稳定的去除盐离子，并且具有较高的吸附容量，表明了连续脱盐的可行性。研究结果对多级MCDI脱盐工程化应用具有指导意义。

Membrane capacitive deionization technology with multi-stage series connection for brine treatment

Membrane capacitive deionization (MCDI) technology has the advantages of simple device, easy operation, easy regeneration, low cost, no pollution, energy saving and so on, which makes it a new desalination technology. In order to improve the desalination performance of MCDI, the water influent of multiple devices was connected in series, and each device was charged separately to explore the influence of its salt removal efficiency (SRE), average salt removal rate (ASRR), energy normalization removal salt (ENRS), and other indicators on the multi-stage series connection. The results showed that under different operating conditions such as influent salt concentration, hydraulic retention time, and voltage, the desalination rate of the second and third stage MCDI series increased by about 2 to 3 times. The desalination rate of the third stage series was slightly improved compared to the second stage series, but it had higher energy consumption. Overall comparison, the desalination performance of the two-stage MCDI series connection was better, and the optimal operating conditions were obtained at 1.5 g·L−1, 0.375 min, 1.2 V. In the continuous desalination process, multi-stage series connection can continuously and stably remove salt ions, and has a high adsorption capacity, indicating the feasibility of continuous desalination. The research results have a guiding significance for the desalination engineering application of multi-stage MCDI.