School of Medical Instrument and Food Engineering, Shanghai Engineering Research Center for Food Rapid Detection, University of Shanghai for Science and Technology, P.O. Box 454, No. 516, Jungong Road, Shanghai, 200093, PR China.
School of Medical Instrument and Food Engineering, Shanghai Engineering Research Center for Food Rapid Detection, University of Shanghai for Science and Technology, P.O. Box 454, No. 516, Jungong Road, Shanghai, 200093, PR China.
Chemosphere. 2021 Sep;278:130369. doi: 10.1016/j.chemosphere.2021.130369. Epub 2021 Mar 24.
A novel monodispersed Cd(II) ion-imprinted polymer (IIP) was synthesized inside core-shell mesoporous silica (C-SMS) particles to improve the diffusion kinetics of the polymer. The synthesized IIP@C-SMS was characterized and subsequently used in solid-phase extraction (SPE) for the selective adsorption of Cd(II) in aquatic samples. The results indicated that IIP had been successfully assembled inside the C-SMS particles with a high specific surface area (546.3 m g) and uniform mesoporous size (2.07 nm). The obtained IIP@C-SMS takes only 15 min to reach the adsorption equilibrium due to the highly developed mesoporous structure. IIP@C-SMS also presented a maximal adsorption capacity (201.9 μmol g) for Cd(II), which was much higher than that of NIP@C-SMS (80.3 μmol g). The relative selectivity coefficient of IIP@C-SMS for Cd(II)/M(II) (M = Cu(II), Pb(II), Cr(II), and Ni(II)) were 7.15, 8.70, 7.18, and 7.36, respectively, further confirming the satisfactory selectivity of IIP@C-SMS. The adsorption isotherms of IIP@C-SMS toward Cd(II) could be described by Langmuir model; whereas the adsorption kinetics could be fitted by the pseudo-second-order model, indicating chemisorption was the rate-limiting step. The FT-IR, ITC and XPS analysis further confirmed that the Cd(II)-induced cavities during the ion-imprinting process and the coordination between Cd(II) and -SH groups were the main adsorption mechanism. Furthermore, in real samples, IIP@C-SMS-SPE adsorbed approximately 93-104% of Cd(II). This work provides new insights for the design of novel macroporous sorbents for Cd(II).
一种新型的单分散 Cd(II) 离子印迹聚合物（IIP）被合成在核壳介孔硅（C-SMS）颗粒内，以改善聚合物的扩散动力学。合成的 IIP@C-SMS 进行了表征，并随后用于固相萃取（SPE），以选择性吸附水样中的 Cd(II)。结果表明，IIP 已成功组装在 C-SMS 颗粒内，具有高比表面积（546.3 m g）和均匀的介孔尺寸（2.07 nm）。由于高度发达的介孔结构，获得的 IIP@C-SMS 仅需 15 分钟即可达到吸附平衡。IIP@C-SMS 对 Cd(II) 的最大吸附容量（201.9 μmol g）也远高于 NIP@C-SMS（80.3 μmol g）。IIP@C-SMS 对 Cd(II)/M(II)（M = Cu(II)、Pb(II)、Cr(II)和 Ni(II)）的相对选择性系数分别为 7.15、8.70、7.18 和 7.36，进一步证实了 IIP@C-SMS 的良好选择性。IIP@C-SMS 对 Cd(II)的吸附等温线可以用 Langmuir 模型描述；而吸附动力学可以用伪二阶模型拟合，表明化学吸附是限速步骤。FT-IR、ITC 和 XPS 分析进一步证实，Cd(II)印迹过程中形成的空腔和 Cd(II)与 -SH 基团之间的配位是主要的吸附机制。此外，在实际样品中，IIP@C-SMS-SPE 吸附了约 93-104%的 Cd(II)。这项工作为设计新型用于 Cd(II)的大孔吸附剂提供了新的思路。
