Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620, China.
Lutai School of Textile and Apparel, Shandong University of Technology, Zibo, Shandong 255049, China.
Carbohydr Polym. 2021 Apr 15;258:117644. doi: 10.1016/j.carbpol.2021.117644. Epub 2021 Jan 19.
A novel citrate-crosslinked Zn-MOF/chitosan (ZnBDC/CSC) composite was successfully prepared by immobilizing Zn-MOF (ZnBDC) on citrate-crosslinked chitosan (CSC) using citric acid as a chemical bridge. ZnBDC/CSC was characterized by XRD, FT-IR, solid-state C NMR, BET and SEM. The adsorption of ZnBDC/CSC for Cr(VI) and MO from aqueous solutions were studied at pH 5.0. The adsorption conditions, such as adsorption time and initial concentration of Cr(VI) and MO solutions were investigated. The results indicated that ZnBDC/CSC showed high adsorption capacity for both Cr(VI) (225 ± 4 mg g) and MO (202 ± 3 mg g), respectively. The adsorption of Cr(VI) on ZnBDC/CSC could be well described by Langmuir isotherm model, while MO followed Freundlich model. The adsorption kinetic of Cr(VI) and MO demonstrated a better fitness to the pseudo-second order kinetic model. Thermodynamic parameters (enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG)) demonstrated that the adsorption processes of Cr(VI) and MO on ZnBDC/CSC were exothermic, disordered and spontaneous at 298-318 K. The adsorption mechanism of ZnBDC/CSC for Cr(VI) could be mainly explained by electrostatic attraction and cation-π interaction, while for MO, it could be assigned to n-π and π-π interactions, electrostatic attraction and hydrogen bonding. ZnBDC/CSC could be recycled and reused for the removal of Cr(VI) and MO.
一种新型的柠檬酸酸化交联的 Zn-MOF/壳聚糖（ZnBDC/CSC）复合材料，通过使用柠檬酸作为化学桥将 Zn-MOF（ZnBDC）固定在柠檬酸酸化交联的壳聚糖（CSC）上成功制备。通过 XRD、FT-IR、固态 C NMR、BET 和 SEM 对 ZnBDC/CSC 进行了表征。研究了在 pH 5.0 下，ZnBDC/CSC 从水溶液中对 Cr(VI)和 MO 的吸附。考察了吸附时间和 Cr(VI)和 MO 溶液的初始浓度等吸附条件。结果表明，ZnBDC/CSC 对 Cr(VI)（225±4mg g）和 MO（202±3mg g）均表现出较高的吸附能力。Cr(VI)在 ZnBDC/CSC 上的吸附可以很好地用 Langmuir 等温模型描述，而 MO 遵循 Freundlich 模型。Cr(VI)和 MO 的吸附动力学更符合准二级动力学模型。热力学参数（焓变 (ΔH)、熵变 (ΔS)和吉布斯自由能变 (ΔG))表明，在 298-318 K 下，Cr(VI)和 MO 在 ZnBDC/CSC 上的吸附过程是放热的、无序的和自发的。ZnBDC/CSC 对 Cr(VI)的吸附机制主要可以解释为静电吸引和阳离子-π 相互作用，而对于 MO，可以归因于 n-π 和 π-π 相互作用、静电吸引和氢键。ZnBDC/CSC 可用于回收和再利用，以去除 Cr(VI)和 MO。
