Abstract

Dithiocarbamate (DTC) was synthesized using tetraethylenepentamine (TEPA) and carbon disulfide as raw materials. The product was characterized by FTIR and its chelating performance of removing lead ion in water was evaluated. The results are shown as follows. Characterization results from the FTIR spectra suggest the target product DTC has been successfully synthesized. The efficiency of removing lead ion or degree of removal increases with removing time, pH value, and DTC dosage, respectively, and then keeps almost unchanged when continuously increasing each of these factors. On the other hand, the degree of removal decreases with the initial concentration of lead ion. Meanwhile, the amount of sorption decreases with the DTC dosage and increases with the initial concentration of lead ion. 99.9% of degree of removal is obtained under a condition including 6 of pH, 220 min of removing time, 3.2 g L^–1 of DTC dosage, and 40 mg L^–1 of initial ion concentration. The relationship between the amount of sorption and equilibrium lead concentration is in good accordance with the isothermal equation of Langmuir model while it is in worse accordance with that of Freundlich model. It suggests that the chelating process is a monolayer coverage resulting from the chemical combination by the DTC groups, namely the chelating active sites. What’s more, the product of chelating reaction between DTC and Pb²⁺ ion is more stable and insoluble in water so that it can be easily separated from the solution. Accordingly, the synthesized DTC in this work is a good reagent for removing Pb²⁺ ion in wastewaters and will be widely used in the field of environment protection.

中文翻译：

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以四亚乙基五胺二硫代氨基甲酸酯为螯合剂去除水中铅离子的性能

摘要

以四亚乙基五胺（TEPA）和二硫化碳为原料合成了二硫代氨基甲酸酯（DTC）。对该产物进行了红外光谱表征，并对其去除水中铅离子的螯合性能进行了评价。结果如下所示。FTIR 光谱的表征结果表明目标产物 DTC 已成功合成。去除铅离子的效率或去除程度分别随着去除时间、pH 值和 DTC 用量而增加，然后随着这些因素中的每一个不断增加，几乎保持不变。另一方面，去除程度随着铅离子初始浓度的增加而降低。同时，吸附量随着DTC用量的增加而减少，随着铅离子初始浓度的增加而增加。99.^–1的 DTC 剂量和 40 mg L ^–1的初始离子浓度。吸附量与平衡铅浓度的关系与Langmuir模型的等温方程吻合较好，而与Freundlich模型的吻合较差。这表明螯合过程是由 DTC 基团（即螯合活性位点）化学结合产生的单层覆盖。此外，DTC与Pb ²⁺离子螯合反应的产物更稳定，不溶于水，易于从溶液中分离。因此，本工作合成的 DTC 是去除 Pb ²⁺的良好试剂。 废水中的离子，将广泛应用于环保领域。