Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 41335-19141, Rasht, Iran.
Environ Monit Assess. 2019 Feb 8;191(3):145. doi: 10.1007/s10661-019-7282-x.
The results of investigations about the polymerization of p-aminophenol in neutral-weak alkaline medium (pH = 7-8) in our lab showed that the produced polymer which was insoluble in water and soluble in methanol has high tendency to form selectively a blue complex with Ni(II). Investigations into the chemical structure of polymer showed that polymer has a special structure, similar to polyamine in which the aromatic rings are connected through O-bridges. Based on these data, it was decided to polymerize p-aminophenol in situ on graphene oxide (GO) and use as a new sorbent for selective separation and preconcentration of trace amount of Ni(II) from water samples. By this, the rate of sorption of Ni(II) will also be increased considerably with respect to GO alone. Resulting composite (GO-Pp-AP) was characterized by FT-IR, XRD, FE-SEM, and EDS. The obtained data confirmed the uniform growth of the polymer on the GO and the absence of granular particles. The composite shows high tendency and high rate of sorption of Ni(II) and consequently was utilized for solid phase extraction (SPE) of Ni(II) ions before its determination by flame atomic absorption (FAAS). The effects of important parameters on the recovery of Ni(II) were investigated. The presence of foreign ions has no meaningful effect on the recovery percentage of Ni(II). Under the optimum conditions, limit of detection and relative standard deviation were found to be 0.70 μg L and 1.8% (for n = 6; at 20 μg L of Ni(II)), respectively. Testing the standard reference material and analyzing the spiked real samples exhibit that the procedure can be successfully employed for determination of Ni(II) in natural water and wastewater samples. Graphical abstract ᅟ.
我们实验室对 p-氨基酚在中性-弱碱性介质（pH = 7-8）中聚合的研究结果表明，所生成的聚合物不溶于水而溶于甲醇，并且具有与 Ni(II) 选择性形成蓝色络合物的高倾向。对聚合物的化学结构进行的研究表明，聚合物具有一种特殊的结构，类似于多胺，其中芳香环通过 O 桥连接。基于这些数据，决定在氧化石墨烯（GO）上原位聚合 p-氨基酚，并将其用作从水样中选择性分离和预浓缩痕量 Ni(II) 的新型吸附剂。通过这种方式，与单独的 GO 相比，Ni(II) 的吸附速率也会大大提高。所得复合材料（GO-Pp-AP）通过 FT-IR、XRD、FE-SEM 和 EDS 进行了表征。获得的数据证实了聚合物在 GO 上的均匀生长，并且不存在颗粒状颗粒。该复合材料对 Ni(II) 表现出高的亲和性和高的吸附速率，因此在火焰原子吸收（FAAS）测定之前，用于 Ni(II)离子的固相萃取（SPE）。研究了重要参数对 Ni(II)回收率的影响。存在外来离子对 Ni(II)的回收率没有有意义的影响。在最佳条件下，检测限和相对标准偏差分别为 0.70μg L 和 1.8%（对于 n = 6；在 20μg L 的 Ni(II)）。对标准参考物质的测试和对加标实际样品的分析表明，该方法可成功用于测定天然水和废水样品中的 Ni(II)。
