Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan.
Daicel Corporation, 1239 Shinzaike, Aboshi-ku, Himeji-Shi, Hyogo, 671-1283, Japan.
Chemosphere. 2022 Nov;307(Pt 1):135671. doi: 10.1016/j.chemosphere.2022.135671. Epub 2022 Jul 13.
Numerous reports have described dithiocarbamate (DTC)-modified cellulose sorbents that can selectively separate metal ions from water. We have previously synthesized a novel sorbent modified with DTC containing N-heterocycles in the backbone for the selective removal of hazardous metal ions. The sorbent was found to partially dissolve and aggregate in solution, reducing its sorption capacity. In this study, to prepare the sorbent for use as a soli-phase extraction material for the removal of arsenite (As) ions, we attempted to decrease the solubility of the sorbent. The sorbent was cross-linked with epoxy or complexed with iron, and the quantities of the modifiers were varied between 3.0 and 10 mol%. As a result, the iron-complexed sorbents were still partially soluble, and cross-linkage with 6.0 mol% of epoxy made the sorbent almost insoluble and dispersed in solution. This sorbent also exhibited the highest As sorption performance among the sorbents synthesized in this study. Although DTC-modified polymers are reported to lose their sorption capability after storage at 40 °C, the sorbent was found to be thermally stable. The optimum contact time and pH for As removal were 20 min and 3.0, respectively. The maximum sorption capacity of the epoxy-cross-linked sorbent, calculated from the Langmuir isotherm equation, was 600 μmol g (45 mg g) at 25 °C. Additionally, the sorbent was highly selective toward As compared with previously reported sorbents and capable of removing approximately 97% of As from environmental water. In conclusion, cross-linking enhances the stability of the sorbents in solutions, which facilitates the removal of As from environmental water.
大量报告描述了二硫代氨基甲酸盐（DTC）修饰的纤维素吸附剂，它可以从水中选择性地分离金属离子。我们之前合成了一种新型的 DTC 修饰的吸附剂，其骨架中含有杂环，可以选择性地去除有害的金属离子。研究发现，该吸附剂在溶液中部分溶解并聚集，从而降低了其吸附能力。在这项研究中，为了制备该吸附剂作为固相萃取材料，用于去除亚砷酸盐（As）离子，我们尝试降低吸附剂的溶解度。通过用环氧或铁进行交联，改变改性剂的用量（3.0-10mol%）。结果表明，铁络合的吸附剂仍然部分可溶，而用 6.0mol%的环氧进行交联则使吸附剂几乎不溶并分散在溶液中。与本研究中合成的其他吸附剂相比，这种吸附剂对 As 的吸附性能最高。尽管据报道，DTC 修饰的聚合物在 40°C 下储存后会失去其吸附能力，但该吸附剂表现出热稳定性。最佳的 As 去除接触时间和 pH 值分别为 20min 和 3.0。根据 Langmuir 等温方程计算的环氧交联吸附剂的最大吸附容量为 600μmol g（25°C 时为 45mg g）。此外，与之前报道的吸附剂相比，该吸附剂对 As 具有较高的选择性，能够从环境水中去除约 97%的 As。总之，交联增强了吸附剂在溶液中的稳定性，这有助于从环境水中去除 As。
