Abstract Reverse osmosis (RO) has been increasingly applied for impaired water reuse in arid areas. However, enhancing RO recovery from scarce water resources is limited by energy demand for overcoming elevated brine osmotic pressure, and membrane scaling caused by concentrated poorly soluble salts. In this study, we present a hybrid ion exchange desalination process (HIX-Desal) as multifunctional RO pretreatment to enhance RO recovery by simultaneously desalinating feed water and removing multiple scale-forming ions (calcium, sulfate, and phosphate). The novelty of HIX-Desal is that carbon dioxide was the sole regenerant for a two-column train containing a hybrid anion exchanger (HAIX, with doped ferric oxide nanoparticles) and a shallow shell weak acid cation exchanger (SSWAC). We probed the desalination abilities of HIX-Desal at both lab and pilot scales using impaired water sources with varying total dissolved solids (TDS), where consistent desalination was achieved at 50–60% TDS reduction. Field tests demonstrated >80% removal of calcium, sulfate, and phosphate simultaneously. System configuration and SSWAC structure, i.e., intraparticle diffusion path length, were demonstrated to govern the HIX-Desal process during desalination and CO2 regeneration cycle. We envision this study to facilitate RO recovery enhancement and upcycling industrial carbon emission.

中文翻译：

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由二氧化碳驱动的多功能离子交换预处理，用于提高水回用受损期间的反渗透回收率

摘要 反渗透 (RO) 越来越多地应用于干旱地区受损的水回用。然而，从稀缺水资源中提高 RO 回收率受到克服盐水渗透压升高的能量需求以及由浓缩的难溶盐引起的膜结垢的限制。在本研究中，我们提出了一种混合离子交换脱盐工艺 (HIX-Desal) 作为多功能反渗透预处理，通过同时对给水进行脱盐和去除多种形成水垢的离子（钙、硫酸盐和磷酸盐）来提高反渗透回收率。HIX-Desal 的新颖之处在于，二氧化碳是包含混合阴离子交换剂（HAIX，掺杂氧化铁纳米颗粒）和浅壳弱酸阳离子交换剂 (SSWAC) 的两柱列的唯一再生剂。我们使用具有不同总溶解固体 (TDS) 的受损水源在实验室和中试规模上探索了 HIX-Desal 的脱盐能力，其中在 TDS 减少 50-60% 的情况下实现了一致的脱盐。现场测试表明，钙、硫酸盐和磷酸盐同时去除了 80% 以上。系统配置和 SSWAC 结构，即粒子内扩散路径长度，被证明在脱盐和 CO2 再生循环期间控制 HIX-Desal 过程。我们设想这项研究将促进 RO 回收率的提高和工业碳排放的升级。系统配置和 SSWAC 结构，即粒子内扩散路径长度，被证明在脱盐和 CO2 再生循环期间控制 HIX-Desal 过程。我们设想这项研究将促进 RO 回收率的提高和工业碳排放的升级。系统配置和 SSWAC 结构，即粒子内扩散路径长度，被证明在脱盐和 CO2 再生循环期间控制 HIX-Desal 过程。我们设想这项研究将促进 RO 回收率的提高和工业碳排放的升级。