Forward osmosis (FO) has been increasingly used for water treatment. However, the lack of suitable draw solutes impedes its further development. Herein, we design pH-responsive polyoxometalates, that is, (NH₄)₆Mo₇O₂₄ and Na₆Mo₇O₂₄, as draw solutes for simultaneous water reclamation and resource recovery from wastewater via FO. Both polyoxometalates have a cage-like configuration and release multiple ionic species in water. These characteristics allow them to generate high osmotic pressures to drive the FO separation efficiently with negligible reverse solute diffusion. (NH₄)₆Mo₇O₂₄ and Na₆Mo₇O₂₄ at a dilute concentration (0.4 M) produce water fluxes of 16.4 LMH and 14.2 LMH, respectively, against DI water, outperforming the frequently used commercial NaCl and NH₄HCO₃ draw solutes, and other synthetic materials. With an average water flux of 10.0 LMH, (NH₄)₆Mo₇O₂₄ reclaims water from the simulated glutathione-containing wastewater more efficiently than Na₆Mo₇O₂₄ (9.1 LMH), NaCl (3.3 LMH), and NH₄HCO₃ (5.6 LMH). The final glutathione treated with (NH₄)₆Mo₇O₂₄ and Na₆Mo₇O₂₄ remains intact but that treated with NaCl and NH₄HCO₃ is either denatured or contaminated owing to their severe leakage in FO. Remarkably, both polyoxometalates are readily recycled by pH regulation and reused for FO. Polyoxometalate is thus proven to be an appropriate candidate for FO separation in wastewater reclamation and resource recovery.

中文翻译：

---

通过正向渗透实现高效废水回收和源头回收的 pH 响应多金属氧酸盐

正向渗透 (FO) 已越来越多地用于水处理。然而，缺乏合适的驱动溶质阻碍了它的进一步发展。在此，我们设计了 pH 响应性多金属氧酸盐，即 (NH ₄ ) ₆ Mo ₇ O ₂₄和 Na ₆ Mo ₇ O ₂₄，作为驱动溶质，通过 FO 从废水中同时回收水和资源。两种多金属氧酸盐都具有笼状构型并在水中释放多种离子物质。这些特性使它们能够产生高渗透压，以有效地驱动 FO 分离，而反向溶质扩散可忽略不计。(NH ₄ ) ₆ Mo ₇ O₂₄和 Na ₆ Mo ₇ O ₂₄在稀释浓度 (0.4 M) 下对去离子水产生的水通量分别为 16.4 LMH 和 14.2 LMH，优于常用的商业 NaCl 和 NH ₄ HCO _{3 驱动}溶质和其他合成材料. 在平均水通量为 10.0 LMH 的情况下，(NH ₄ ) ₆ Mo ₇ O ₂₄比 Na ₆ Mo ₇ O ₂₄ (9.1 LMH)、NaCl (3.3 LMH) 和 NH ₄更有效地从模拟含谷胱甘肽废水中回收水碳酸氢盐₃(5.6 LMH)。用 (NH ₄ ) ₆ Mo ₇ O ₂₄和 Na ₆ Mo ₇ O ₂₄处理的最终谷胱甘肽保持完整，但用 NaCl 和 NH ₄ HCO ₃处理的谷胱甘肽由于它们在 FO 中的严重泄漏而变性或被污染。值得注意的是，这两种多金属氧酸盐很容易通过 pH 调节回收并重新用于 FO。因此，多金属氧酸盐被证明是废水回收和资源回收中 FO 分离的合适候选者。