Wu Nan, Levant Michael, Brahmi Youcef, Tregouet Corentin, Colin Annie
ESPCI Paris, PSL Research University, MIE-CBI, CNRS UMR 8231, 10, Rue Vauquelin, 75231, Paris Cedex 05, France.
Total Energies, PERL - Pôle d'Etudes et de Recherches de Lacq, 64170, Lacq, France.
Sci Rep. 2024 Jul 23;14(1):16984. doi: 10.1038/s41598-024-67690-7.
In recent years, the energy generated by the salinity gradient has become a subject of growing interest as a source of renewable energy. One of the most widely used processes is reverse electrodialysis (RED), based on the use of ion exchange membranes and Faradaic electrodes. However, the use of real salt solutions containing mixtures of divalent and monovalent ions in the RED process results in a significant loss of recovered power, compared with salt solutions containing only monovalent ions. From an original point of view, in this work we study and explain the influence of divalent ions and complex solutions in reverse electrodialysis devices equipped with capacitive electrodes with a single membrane (CREDSM). We show that CREDSM mitigates the impact of divalent ions. From a quantitative point of view, the power recovered in a Faradaic cell drops by more than 75 when the solutions contain 50 molar fraction of divalent ions and by 33 when the solutions contain 10 molar fraction of divalent ions. For similar low-cost membranes with fairly low selectivity, recovered power drops by only 34 when solutions contain 60 moles of divalent ions in CREDSM. We show that only the membrane potential, which makes up half of the cell's open circuit potential, is affected. The potential of capacitive electrodes which counts for half of the potential cell does not decrease in the presence of divalents. For the same membrane under the same conditions, we estimate a loss of 62 in a RED device Furthermore, the membrane is not poisoned by divalent ions because we periodically change the electrical current direction, by means of switching the feed waters. CREDSM devices do not show any variation in membrane resistance or membrane selectivity. The techno-economic analysis suggests further valorization of salinity gradients in industrial operations.
近年来，盐度梯度产生的能量作为一种可再生能源来源，已成为人们越来越感兴趣的课题。最广泛使用的过程之一是反向电渗析（RED），它基于离子交换膜和法拉第电极的使用。然而，与仅含单价离子的盐溶液相比，在RED过程中使用含有二价和单价离子混合物的实际盐溶液会导致回收功率显著损失。从一个全新的角度出发，在这项工作中，我们研究并解释了二价离子和复合溶液在配备单膜电容电极的反向电渗析装置（CREDSM）中的影响。我们表明，CREDSM减轻了二价离子的影响。从定量的角度来看，当溶液中二价离子的摩尔分数为50%时，法拉第电池中回收的功率下降超过75%，当溶液中二价离子的摩尔分数为10%时，回收功率下降33%。对于具有相当低选择性的类似低成本膜，在CREDSM中当溶液含有60摩尔二价离子时，回收功率仅下降34%。我们表明，仅占电池开路电位一半的膜电位受到影响。占电位电池一半的电容电极电位在存在二价离子时不会降低。在相同条件下，对于同一膜，我们估计在RED装置中的损失为62%。此外，膜不会被二价离子中毒，因为我们通过切换进水来定期改变电流方向。CREDSM装置的膜电阻或膜选择性没有任何变化。技术经济分析表明，盐度梯度在工业运营中还有进一步的利用价值。
