College of Resources and Environment, Hubei University of Technology, Wuhan 430068, China.
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Molecules. 2023 Jun 6;28(12):4576. doi: 10.3390/molecules28124576.
Concentration followed by electrolysis is one of the most promising ways for saline wastewater treatment, since it could produce H, Cl and an alkaline solution with deacidification potential. However, due to the diversity and difference of wastewater, knowledge on the suitable salt concentration for wastewater electrolysis and the effects of mixed ions are still lacking. In this work, electrolysis experiments of mixed saline water were conducted. The salt concentration for stable dechlorination was explored, with in-depth discussions on the effects of typical ions such as K, Ca, Mg, and SO. Results showed that K had a positive effect on the H/Cl production of saline wastewater through accelerating the mass transfer efficiency in the electrolyte. However, the existence of Ca and Mg had negative effects on the electrolysis performance by forming precipitates, which would adhere to the membrane, reduce the membrane permeability, occupy the active sites on the cathode surface, and also increase the transport resistance of the electrons in the electrolyte. Compared to Mg, the damaging effect of Ca on the membrane was even worse. Additionally, the existence of SO reduced the current density of the salt solution by affecting the anodic reaction while having less of an effect on the membrane. Overall, Ca ≤ 0.01 mol/L, Mg ≤ 0.1 mol/L and SO ≤ 0.01 mol/L were allowable to ensure the continuous and stable dechlorination electrolysis of saline wastewater.
浓缩后电解是处理盐废水最有前途的方法之一，因为它可以产生 H、Cl 和具有脱酸潜力的碱性溶液。然而，由于废水的多样性和差异性，对于适合废水电解的盐浓度以及混合离子的影响的知识仍然缺乏。在这项工作中，进行了混合盐水的电解实验。探索了稳定脱氯的盐浓度，并深入讨论了 K、Ca、Mg 和 SO 等典型离子的影响。结果表明，K 通过加速电解质中的传质效率对盐水废水的 H/Cl 生产有积极影响。然而，Ca 和 Mg 的存在通过形成沉淀物对电解性能产生负面影响，这些沉淀物会附着在膜上，降低膜的渗透性，占据阴极表面的活性位点，并增加电解质中电子的传输阻力。与 Mg 相比，Ca 对膜的破坏作用甚至更严重。此外，SO 的存在通过影响阳极反应而降低盐溶液的电流密度，对膜的影响较小。总体而言，Ca≤0.01mol/L、Mg≤0.1mol/L 和 SO≤0.01mol/L 是允许的，以确保盐水废水的连续稳定脱氯电解。
