Abstract:

The Donnon dialysis-zerovalent iron combined process was developed by adding zerovalent iron into the stripping solution. The arsenic adsorption by the zerovalent iron corrosion products was able to regenerate the stripping solution in situ. Therefore, the long-term arsenic removal by the Donnan dialysis system was markedly improved. In this study, the effect of NaCl concentration in the desorption solution was determined to be 0.1 mol·L^-1 based on the investigation of the effect of the NaCl concentration in the desorption solution on the arsenic removal performance of zero-valent iron. Then, the proposed Donnon dialysis-zerovalent iron combined process was used to treat arsenic containing well water for multiple batches, using stripping solution containing 6 g common salt and 5 g zerovalent iron per liter. The arsenic concentrations in the treated water was constantly below 50 μg·L^-1 for 20 batches, much lower than the performance of the single Donnan dialysis system. The coupling of Donnan dialysis with zerovalent iron prolonged the interval for the stripping solution replacement; therefore, the practical application of the Donnan dialysis household water purifier was significantly improved.

Key words: ion exchange, adsorption, regeneration, zerovalent iron, Donnan dialysis

摘要：

道南渗析-零价铁耦合工艺通过在解吸液中加入零价铁，利用其腐蚀产生的吸附除砷作用，实现解吸液的同步再生，从而改善道南渗析除砷系统长期运行效果。在考察解吸液NaCl浓度对零价铁除砷性能影响的基础上确定解吸液中NaCl浓度为0.1 mol·L^-1。以该工艺对某农村含砷井水的多批次处理结果表明，在6 g·L^-1食盐溶液的解吸液中加入5 g·L^-1还原铁粉后，系统连续运行20批次，出水中砷浓度始终低于50 μg·L^-1，运行有效性远高于单一道南渗析对照组。该耦合工艺延长了解吸液使用时间，提升了道南渗析除砷装置的应用性。

关键词: 离子交换, 吸附, 再生, 零价铁, 道南渗析