School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi, 710055, China.
School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi, 710055, China.
J Hazard Mater. 2020 Jan 5;381:120943. doi: 10.1016/j.jhazmat.2019.120943. Epub 2019 Jul 30.
A Chitosan/polydopamine@C@magnetic fly ash (CPCMFA) adsorbent bead was prepared for adsorption of Ag (Ⅰ) in aqueous solutions and exhibited good selectivity for Ag (Ⅰ) ion. To investigate its adsorption behaviors, equilibrium, kinetic and selective studies were conducted through batch experiments. Additionally, the influence of the pH value was also evaluated. In addition, the nature, composition, morphology, and magnetic property of the prepared adsorbent beads were characterized by Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating-sample magnetometry (VSM). The freeze-dry form of CPCMFA also exhibited high adsorption capacity and selectivity for Ag (Ⅰ), with a maximum adsorption capacity of 57.02 mg/g at pH 4 and 30 °C. The experimental data were well described by the Langmuir isotherm and elovich kinetic models. The thermodynamics parameters, ΔH = 10.653 kJ/mol, ΔS = 96.63 J/mol K and ΔG < 0, demonstrate that the adsorption of Ag (Ⅰ) on the freeze-dry form adsorbent is spontaneous and endothermic. Moreover, regeneration studies showed the high recyclability of the adsorbent, which after five cycles of use it was still able to adsorb 95.7% of the amount adsorbed by the fresh adsorbent.
壳聚糖/聚多巴胺@C@磁性粉煤灰（CPCMFA）吸附珠被制备用于吸附水溶液中的 Ag（Ⅰ），并对 Ag（Ⅰ）离子表现出良好的选择性。为了研究其吸附行为，通过批量实验进行了平衡、动力学和选择性研究。此外，还评估了 pH 值的影响。此外，通过傅里叶变换红外（FT-IR）光谱、X 射线衍射（XRD）分析、热重-差示扫描量热（TG-DSC）分析、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和振动样品磁强计（VSM）对制备的吸附珠的性质、组成、形态和磁性进行了表征。CPCMFA 的冻干形式也表现出对 Ag（Ⅰ）的高吸附容量和选择性，在 pH 值为 4 和 30°C 时最大吸附容量为 57.02 mg/g。实验数据很好地符合 Langmuir 等温线和 Elovich 动力学模型。热力学参数ΔH=10.653 kJ/mol、ΔS=96.63 J/mol K 和ΔG<0 表明 Ag（Ⅰ）在冻干形式吸附剂上的吸附是自发和吸热的。此外，再生研究表明吸附剂具有高的可回收性，经过五次使用循环后，它仍然能够吸附新鲜吸附剂吸附量的 95.7%。
