Xie Xinling, Zhao Xiaona, Luo Xuan, Zhang Youquan, Qin Zuzeng, Ji Hongbing
Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China.
Nanomaterials (Basel). 2023 Jan 27;13(3):513. doi: 10.3390/nano13030513.
The magnetic polymer microsphere is a promising adsorbent due to its high adsorption efficiency and good regeneration ability from wastewater. Cassava starch magnetic porous microspheres (AAM-MSMPMs) were synthesized by graft copolymerization in inverse emulsion. Mechanically activated cassava starch (MS) was used to graft skeletons, vinyl monomers [acrylic acid (AA) and acrylamide (AM)] as copolymerized unsaturated monomers, methyl methacrylate (MMA) as the dispersing agent, and polyethylene glycol/methanol (PEG2000/MeOH) as the porogen. It was found that the AAM-MSMPM adsorbent is superparamagnetic, the saturation magnetization is 14.9 emu·g, and it can be rapidly and directionally separated from Cd(II) ions in aqueous solution. The FTIR indicated that the carboxyl and hydroxyl groups were grafted into MS. The AAM-MSMPM had good speroidization and a uniform size. After the porogen was added, the particle size of the AAM-MSMPM decreased from 19.00 to 7.00 nm, and the specific surface area increased from 7.00 to 35.00 m·g. The pore volume increased from 0.03 to 0.13 cm·g. The AAM-MSMPM exhibited a large specific surface area and provided more adsorption active sites for Cd(II) ions. The maximum adsorption capacity of the AAM-MSMPM for Cd(II) ions was 210.68 mg·g, i.e., 81.02% higher than that without porogen. Additionally, the Cd(II) ion adsorption process on the AAM-MSMPM can be described by Langmuir isothermal and pseudo-second-order kinetic models. A chemical reaction dominated the Cd(II) ion adsorption process on the AAM-MSMPM, and chemisorption was the rate-controlling step during the Cd(II) ion adsorption process. The AAM-MSMPM still had excellent stability after five consecutive reuses.
磁性聚合物微球因其高吸附效率和良好的从废水中再生的能力而成为一种很有前景的吸附剂。木薯淀粉磁性多孔微球（AAM-MSMPMs）通过反相乳液中的接枝共聚法合成。机械活化木薯淀粉（MS）用于接枝骨架，乙烯基单体[丙烯酸（AA）和丙烯酰胺（AM）]作为共聚不饱和单体，甲基丙烯酸甲酯（MMA）作为分散剂，聚乙二醇/甲醇（PEG2000/MeOH）作为致孔剂。结果发现，AAM-MSMPM吸附剂具有超顺磁性，饱和磁化强度为14.9 emu·g，并且可以在水溶液中快速、定向地从Cd(II)离子中分离出来。傅里叶变换红外光谱（FTIR）表明羧基和羟基接枝到了MS上。AAM-MSMPM具有良好的球形度且尺寸均匀。加入致孔剂后，AAM-MSMPM的粒径从19.00减小到7.00 nm，比表面积从7.00增加到35.00 m·g。孔容从0.03增加到0.13 cm·g。AAM-MSMPM表现出较大的比表面积，为Cd(II)离子提供了更多的吸附活性位点。AAM-MSMPM对Cd(II)离子的最大吸附容量为210.68 mg·g，即比没有致孔剂时高81.02%。此外，AAM-MSMPM上Cd(II)离子的吸附过程可以用朗缪尔等温线和准二级动力学模型来描述。化学反应主导了AAM-MSMPM上Cd(II)离子的吸附过程，化学吸附是Cd(II)离子吸附过程中的速率控制步骤。AAM-MSMPM在连续五次重复使用后仍具有优异的稳定性。
