Abstract Zeolite membranes have been widely examined for desalination. Work to date has shown effective performance in monovalent rich solutions, but the understanding of the unique ion-zeolite interactions for multivalent ion rich solutions, such as those found in acidic mining wastewaters, has not yet been studied. Filtration performance of MFI-type zeolite membrane was evaluated on a model multivalent ion, Fe 3 + , Al 3 + , Ca 2 + and Mg 2 + , solution with total dissolved solids (TDS) of 97,000 mg L − 1 and pH 2.03 at between 3 MPa and 7 MPa and 21 °C to 70 °C. At 7 MPa and 21 °C, rejection for Fe 3 + was 97%, 80% for Al 3 + and Mg 2 + , and 50% for Ca 2 + . This behaviour followed the rejection of ions with larger hydrated diameter, except for Al 3 + which was attributed to its unique strong interaction with zeolites. However, an unusual trend of increasing rejection with increasing temperature was observed. Instead of activated transport which occurs with monovalent or dilute solutions, temperature accelerated the infiltration of multivalent ions into the zeolite structure to further block ions and synergistically increased rejection. Zeolite membranes exhibited unique effects in multivalent ion rich solution that could be further utilised in niche desalination applications or benefit other applications such as sensors.

中文翻译：

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多价离子在低 pH 值下通过 MFI 型沸石膜的扩散行为

摘要 沸石膜已被广泛用于海水淡化。迄今为止的工作已显示出在富含一价离子的溶液中的有效性能，但尚未研究对富含多价离子的溶液（例如在酸性采矿废水中发现的溶液）的独特离子-沸石相互作用的理解。MFI 型沸石膜的过滤性能在模型多价离子 Fe 3 + 、Al 3 + 、Ca 2 + 和 Mg 2 + 、总溶解固体 (TDS) 为 97,000 mg L - 1 且 pH 值为 2.03 的溶液中进行评估3 MPa 至 7 MPa 和 21 °C 至 70 °C。在 7 MPa 和 21 °C 下，Fe 3 + 的剔除率为 97%，Al 3 + 和 Mg 2 + 为 80%，Ca 2 + 为 50%。这种行为伴随着具有较大水合直径的离子的排斥，除了 Al 3 + ，这归因于其与沸石的独特强相互作用。然而，观察到随温度升高拒绝率增加的异常趋势。与单价或稀释溶液中发生的活化传输不同，温度加速了多价离子渗入沸石结构，以进一步阻断离子并协同增加排斥。沸石膜在多价离子丰富的溶液中表现出独特的效果，可进一步用于利基海水淡化应用或使传感器等其他应用受益。