This study experimentally confirmed the self-inhibition mechanism of competing ions in a commercially available standard ion-exchange resin (IER) column process in order to realize selective removal of target problematic ions from feedwater using eight anions. The removal of SO₄²⁻ (or HPO₄²⁻, I⁻, BrO₃⁻, as competing ions) from binary feedwater during exhaustion was completely inhibited (<5 % removal) following circular activation of the standard IER column by binary brine with the critical SO₄²⁻ (or HPO₄²⁻, I⁻, BrO₃⁻) equivalent fraction (EF[brine]) of 0.93 (or 0.93, 0.28, 0.44) (with Cl⁻ as mobile counterion). Negligible changes in the critical SO₄²⁻ EF(brine) values (92–94 %) or the critical SO₄²⁻ equivalent fractions in the IER phase (∼70 %) were observed when the SO₄²⁻ equivalent fractions in the SO₄²⁻-Cl⁻ binary feedwater changed substantially (15–65 %). The introduction of MoO₄²⁻, NO₃⁻, or HCO₃⁻ (as coexisting ion) into the SO₄²⁻-Cl⁻ binary feedwater also had a negligible effect on the critical SO₄²⁻ EF(brine) values (82–84 %). The complete inhibition of SO₄²⁻ removal from high-salinity SO₄²⁻-Cl⁻ binary feedwater (∼10 % salinity) during exhaustion was realized even when low-salinity SO₄²⁻-Cl⁻ binary brine (∼1 % salinity) was used. The complete self-inhibition of Cl⁻ or BrO₃⁻ having the lowest selectivity sequence during exhaustion was realized even when SO₄²⁻ having the highest selectivity sequence was used as the mobile counterion. These results provide new knowledge concerning the classic ion-exchange mechanism developed 70 years ago, and will facilitate improved design and operation of the standard IER-based selective ion removal process.

中文翻译：

---

竞争性离子的自抑制机制，可在标准离子交换树脂填充柱工艺中实现低成本、高选择性的离子去除


本研究通过实验证实了市售标准离子交换树脂 （IER） 塔工艺中竞争离子的自抑制机制，以实现使用 8 个阴离子从给水中选择性去除目标问题离子。在用临界 SO₄²⁻（或 HPO ₄²⁻、I⁻、BrO ₃⁻） 等效馏分 （EF[盐水]）为 0.93（或 0.93、0.28、0.44）（以 Cl⁻ 作为移动对离子）。当 SO₄²⁻-Cl⁻ 二元给水中的关键 SO₄²⁻ EF（盐水）值 （92-94%） 或临界 SO ^{4 2− 当}量馏分发生重大变化 （15-65%） 时，观察到 IER 阶段临界 SO₄²⁻ EF（盐水）值 （92-94%） 或临界 SO₄ 2− 当量馏分 （∼70%） 的变化可以忽略不计。将 MoO₄²⁻、NO₃⁻ 或 HCO₃⁻（作为共存离子）引入 SO₄²⁻ Cl⁻ 二元给水中，对临界 SO₄²⁻ EF（盐水）值 （82-84%） 的影响也可以忽略不计。 即使使用低盐度 SO₄²⁻-Cl⁻ 二元盐水（∼1 % 盐度），在枯竭过程中也能完全抑制从高盐度 SO₄²⁻-Cl⁻ 二元给水中去除 SO₄²⁻ 即使使用∼1 % 盐度）。即使使用具有最高选择性序列的 SO₄²⁻ 作为移动对离子，在耗竭过程中也实现了具有最低选择性序列的 Cl⁻ 或 BrO₃⁻ 的完全自抑制。这些结果为70年前开发的经典离子交换机制提供了新的知识，并将有助于改进基于IER的标准选择性离子去除工艺的设计和操作。