Department of Chemical Engineering, Kongju National University, 34 Gongupdae-gil, Seobuk-gu, Cheonan-si, Chungnam 331-717, South Korea.
Water Res. 2012 Nov 15;46(18):6033-9. doi: 10.1016/j.watres.2012.08.031. Epub 2012 Aug 31.
We fabricated nitrate-selective composite carbon electrodes (NSCCEs) for use in capacitive deionization to remove nitrate ions selectively from a solution containing a mixture of anions. The NSCCE was fabricated by coating the surface of a carbon electrode with the anion exchange resin, BHP55, after grinding the resin into fine powder. BHP55 is known to be selective for nitrate ions. We performed desalination experiments on a solution containing 5.0 mM NaCl and 2.0 mM NaNO(3) using the NSCCE system constructed with the fabricated electrode. The selective removal of nitrate in the NSCCE system was compared to a membrane capacitive deionization (MCDI) system constructed with ion exchange membranes and carbon electrodes. The total quantity of chloride and nitrate ions adsorbed onto the unit area of the electrode in the MCDI system was 25 mmol/m(2) at a cell potential of 1.0 V. The adsorption of nitrate ions was 8.3 mmol/m(2), accounting for 33% of the total. In contrast, the total anion adsorption in the NSCCE system was 34 mmol/m(2), 36% greater than the total anion adsorption of the MCDI system. The adsorption of nitrate ions was 19 mmol/m(2), 2.3-times greater than the adsorption in the MCDI system. These results showed that the ions were initially adsorbed by an electrostatic force, and the ion exchange reactions then occurred between the resin powder in the coated layer and the solution containing mixed anions.
我们制备了用于电容去离子的硝酸盐选择性复合碳电极 (NSCCE)，以从含有混合阴离子的溶液中选择性地去除硝酸盐离子。NSCCE 是通过将阴离子交换树脂 BHP55 研磨成细粉后涂覆在碳电极表面而制备的。BHP55 被认为对硝酸盐离子具有选择性。我们使用制备的电极构建的 NSCCE 系统对含有 5.0 mM NaCl 和 2.0 mM NaNO(3)的溶液进行了脱盐实验。将 NSCCE 系统中硝酸盐的选择性去除与由离子交换膜和碳电极构建的膜电容去离子 (MCDI) 系统进行了比较。在 MCDI 系统中，在 1.0 V 的电池电势下，单位面积电极上吸附的氯离子和硝酸盐离子的总量为 25 mmol/m(2)。吸附的硝酸盐离子为 8.3 mmol/m(2)，占总量的 33%。相比之下，NSCCE 系统中的总阴离子吸附量为 34 mmol/m(2)，比 MCDI 系统的总阴离子吸附量多 36%。吸附的硝酸盐离子为 19 mmol/m(2)，比 MCDI 系统的吸附量多 2.3 倍。这些结果表明，离子最初是通过静电力吸附的，然后树脂粉末在涂层中与含有混合阴离子的溶液之间发生离子交换反应。
