Capability of cation exchange technology to remove proven N-nitrosodimethylamine precursors
Capability of cation exchange technology to remove proven N-nitrosodimethylamine precursors
复制标题
阳离子交换技术去除已证实的 N-亚硝基二甲胺前体的能力
DOI：
10.1016/j.jes.2017.04.007
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发表时间：
2017
影响因子：
6.9
通讯作者：
Chen Chao
中科院分区：
文献类型：
--
作者：
Li Shixiang;Zhang Xulan;Bei Er;Yue Huihui;Lin Pengfei;Wang Jun;Zhang Xiaojian;Chen Chao
N-亚硝基二甲胺 (NDMA) 前体由带正电荷的二甲胺基团和非极性部分组成，这启发我们开发一种靶向阳离子交换技术来去除 NDMA 前体。在本研究中，我们测试了强酸性阳离子交换树脂对两种代表性 NDMA 前体二甲胺 (DMA) 和雷尼替丁 (RNTD) 的去除效果。结果表明，pH 值对交换效率影响很大，当交换容量与前驱体的摩尔比为 4 时，在 pH < pka-1 时观察到较高的去除率（DMA > 78% 和 RNTD > 94%）。交换顺序为：Ca2+> Mg2+> RNTD+> K+> DMA+> NH4+> Na+。 DMA+对Na+的分配系数为1.41±0.26，而RNTD+对Na+的分配系数为12.1±1.9。伪二阶方程很好地拟合了阳离子交换动力学。在软化柱测试中发现Ca2+等二价无机阳离子对NA前体的去除有显着影响。除了 DMA 和 RNTD 之外，阳离子交换工艺也可以很好地去除其他 7 种模型 NDMA 前体。总体而言，去除 NDMA 前体可能是利用阳离子交换水软化工艺的另一个好处。
N-nitrosodimethylamine (NDMA) precursors consist of a positively charged dimethylamine group and a non-polar moiety, which inspired us to develop a targeted cation exchange technology to remove NDMA precursors. In this study, we tested the removal of two representative NDMA precursors, dimethylamine (DMA) and ranitidine (RNTD), by strong acidic cation exchange resin. The results showed that pH greatly affected the exchange efficiency, with high removal (DMA > 78% and RNTD > 94%) observed at pH < pka-1 when the molar ratio of exchange capacity to precursor was 4. The exchange order was obtained as follows: Ca2 +> Mg2 +> RNTD+> K+> DMA+> NH4+> Na+. The partition coefficient of DMA+to Na+was 1.41 ± 0.26, while that of RNTD+to Na+was 12.1 ± 1.9. The pseudo second-order equation fitted the cation exchange kinetics well. Bivalent inorganic cations such as Ca2 +were found to have a notable effect on NA precursor removal in softening column test. Besides DMA and RNTD, cation exchange process also worked well for removing other 7 model NDMA precursors. Overall, NDMA precursor removal can be an added benefit of making use of cation exchange water softening processes.