In this study, NaTi₂(PO₄)₃ (NTP) nanoparticles were incorporated into a carbon nanotube hollow-fiber (CHF) electrode for the selective removal of Na⁺ during the capacitive deionization (CDI) of salty water. Due to the Na⁺-selective electro-sorption of NTP nanoparticles, NTP-CHF achieved 1.5 ~2 times higher Na⁺ adsorption capacity than that of CHF only electrodes at a range of 1.7 mM~17.1 mM (100 mg L⁻¹~1000 mg L⁻¹) NaCl solution. Moreover NTP-CHF sustained the Na⁺ adsorption capacity even at the presence of Ca²⁺ ions, whereas the dramatic decrease in Na⁺ removal was observed in CHF with an increase of Ca²⁺ concentration. As the result, NTP-CHF can retain 52% of the initial Na⁺ removal capacity after three times of capture and release cycles at the presence of Ca²⁺, while CHF showed <10% of the initial Na⁺ removal capacity due to the irreversible adsorption of Ca²⁺ ions onto the MWCNT surface. Thus, the incorporation of NTP into the conductive carbon nanomaterial network can greatly improve both the adsorption capacity and selectivity of Na⁺ compared to the conventional carbon-based electrode during the CDI of salty water containing multivalent cations such as Ca²⁺.

在这项研究中，将 NaTi ₂ (PO ₄ ) ₃ (NTP) 纳米颗粒掺入碳纳米管中空纤维 (CHF) 电极中，用于在盐水的电容去离子 (CDI) 过程中选择性去除 Na ^{+ 。}由于 NTP 纳米颗粒的 Na ^+选择性电吸附，NTP-CHF在 1.7 mM~17.1 mM (100 mg L ^-1 ~1000 mg L ^-1 ) NaCl溶液。此外，NTP-CHF即使在存在 Ca ²⁺离子的情况下也能维持 Na ⁺吸附能力，而 Na ^{+的显着降低随着 Ca 2+}浓度的增加，在 CHF 中观察到去除。结果，在存在 Ca ²⁺的情况下，NTP-CHF在 3 次捕获和释放循环后可以保留 52% 的初始 Na ⁺去除能力，而 CHF 表现出 <10% 的初始 Na ⁺去除能力，因为Ca ²⁺离子不可逆地吸附到 MWCNT 表面。^{因此，在含有Ca 2+}等多价阳离子的盐水的CDI过程中，与传统的碳基电极相比，将NTP结合到导电碳纳米材料网络中可以大大提高Na ⁺的吸附容量和选择性。