College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China E-mail:
Water Sci Technol. 2021 Jan;83(2):449-462. doi: 10.2166/wst.2020.593.
Poly(acrylamide) grafted and glutaraldehyde-crosslinked alginic acid nano-magnetic adsorbent (AAMA) was prepared by selecting Cd as a template ion. Scanning electron microscope (SEM), thermo-gravimetric analyzer (TGA), vibrating sample magnetometer (VSM) and infrared spectroscopy (IR) were used to characterize the morphology and structure of AAMA. The adsorption of AAMA for different metal ions was compared and the impact of various factors for adsorption of Cd was systematically investigated. These results suggested that the AAMA was the aggregates of FeO nanoparticles with a diameter of about 50-100 nm and had selectivity for Cd adsorption. The maximum adsorption capacity for Cd is 175 mg/g at pH 5.0 and 303 K. The experimental data were well described by the Langmuir isotherm model and pseudo-second-order model. The parameters of adsorption thermodynamics concluded that the adsorption progress is spontaneous and endothermic in nature. The parameters of adsorption activation energy suggested that there is physical adsorption and chemisorption on the adsorption of metal ions. AAMA could be regenerated by EDTA and still keep 71% adsorption capacity in the fifth consecutive adsorption-regeneration cycle. Therefore, AAMA would be useful as a selective and high adsorption capacity nano-magnetic adsorbent in the removal of Cd from wastewater.
聚（丙烯酰胺）接枝和戊二醛交联的海藻酸纳米磁性吸附剂（AAMA）是通过选择 Cd 作为模板离子制备的。扫描电子显微镜（SEM）、热重分析仪（TGA）、振动样品磁强计（VSM）和红外光谱（IR）用于表征 AAMA 的形态和结构。比较了 AAMA 对不同金属离子的吸附，并系统研究了各种因素对 Cd 吸附的影响。结果表明，AAMA 是 FeO 纳米颗粒的聚集体，直径约为 50-100nm，对 Cd 吸附具有选择性。在 pH5.0 和 303K 时，Cd 的最大吸附容量为 175mg/g。实验数据很好地符合 Langmuir 等温线模型和准二级动力学模型。吸附热力学参数表明，吸附过程是自发和吸热的。吸附活化能参数表明，在金属离子的吸附过程中存在物理吸附和化学吸附。AAMA 可以用 EDTA 再生，在第五次连续吸附-再生循环中仍保持 71%的吸附容量。因此，AAMA 可用作从废水中去除 Cd 的选择性和高吸附容量的纳米磁性吸附剂。
