Abdel-Raouf Manar El-Sayed, Farag Reem Kamal, Farag Ahmed A, Keshawy Mohamed, Abdel-Aziz Alaa, Hasan Abdulraheim
Egyptian Petroleum Research Institute, 1 Ahmed El-Zomor Street, Nasr City, Cairo 11727, Egypt.
ACS Omega. 2023 Mar 6;8(11):10086-10099. doi: 10.1021/acsomega.2c07264. eCollection 2023 Mar 21.
Modified uncrosslinked and crosslinked chitosan derivatives were investigated as green sorbents for the removal of copper (Cu) and lead (Pb) cations from simulated solutions. In this regard, N, O carboxymethyl chitosan (N, O CMC), chitosan beads (Cs-g-GA), chitosan crosslinked with glutaraldehyde/methylene bisacrylamide (Cs/GA/MBA), and chitosan crosslinked with GA/epichlorohydrin (Cs/GA/ECH) were prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy analyses. Atomic force microscopy investigation was carried out to compare the surface topography of the prepared samples before and after the metal uptake. The kinetics of the removal process were investigated by pseudo-first-order and -second-order models. Moreover, the adsorption isotherms were carefully studied by applying Langmuir and Freundlich models. The data reveal that upon adsorption of copper(II) metal ions, all chitosan-modified products followed the Langmuir isotherm except for Cs/GA/ECH which followed the Freundlich isotherms, and the highest adsorption capacity ( ) was obtained for Cs/GA/MBA due to the formation of stable chelate structures between the metal cation and the functional groups present on the modified chitosan product. The order of metal uptake at the optimum pH value is as follows: Cs/GA/MBA (Cu: 95.7 mg/g, Pb: 99.15 mg/g), Cs/GA/ECH (Cu: 80.4 mg/g, Pb: 93.14 mg/g), Cs-g-GA (Cu: 77 mg/g, Pb: 88.4 mg/g), and N, O CMCh (Cu: 30.2 mg/g, Pb: 44.8 mg/g). The AFM data confirmed the metal uptake process by comparing the roughness and height measurements of the free sorbents and the metal-loaded sorbents.
研究了改性的未交联和交联壳聚糖衍生物作为绿色吸附剂从模拟溶液中去除铜（Cu）和铅（Pb）阳离子的性能。在此方面，制备了N，O-羧甲基壳聚糖（N，O-CMC）、壳聚糖珠（Cs-g-GA）、用戊二醛/亚甲基双丙烯酰胺交联的壳聚糖（Cs/GA/MBA）以及用GA/环氧氯丙烷交联的壳聚糖（Cs/GA/ECH），并通过傅里叶变换红外光谱、X射线衍射、热重分析和扫描电子显微镜分析对其进行了表征。进行了原子力显微镜研究以比较制备的样品在金属吸附前后的表面形貌。通过准一级和二级模型研究了去除过程的动力学。此外，应用朗缪尔和弗伦德里希模型仔细研究了吸附等温线。数据表明，在吸附铜（II）金属离子时，除了遵循弗伦德里希等温线的Cs/GA/ECH外，所有壳聚糖改性产物均遵循朗缪尔等温线，并且由于金属阳离子与改性壳聚糖产物上存在的官能团之间形成了稳定的螯合结构，Cs/GA/MBA获得了最高的吸附容量（ ）。在最佳pH值下金属吸附顺序如下：Cs/GA/MBA（Cu：95.7 mg/g，Pb：99.15 mg/g）、Cs/GA/ECH（Cu：80.4 mg/g，Pb：93.14 mg/g）、Cs-g-GA（Cu：77 mg/g，Pb：88.4 mg/g）和N，O-CMCh（Cu：30.2 mg/g，Pb：44.8 mg/g）。原子力显微镜数据通过比较游离吸附剂和负载金属的吸附剂的粗糙度和高度测量结果证实了金属吸附过程。
