Lin Zongkun, Yang Yuru, Liang Zizhan, Zeng Lei, Zhang Aiping
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
Polymers (Basel). 2021 Jun 7;13(11):1891. doi: 10.3390/polym13111891.
In order to avoid the secondary pollution of the toxic residue of chemical crosslinking agent accompanied by chemical hydrogel adsorbent and enhance the adsorption performance of physical hydrogel, chitosan/calcium alginate/bentonite (CTS/CA/BT) composite physical hydrogel was constructed. The formation mechanism and structure of the composite hydrogel were determined by FTIR, XRD and SEM. Adsorption performances of the hydrogel toward Pb, Cu and Cd in water under different condition as well as multi-ion competitive sorption were investigated. The adsorption processes were described with the canonical adsorption kinetics and isotherms models. With the utilization of XPS analysis and adsorption thermodynamics analysis, it was found that the adsorptions were spontaneous physico-chemical adsorptions. The results showed that the maximum adsorption capacity of the hydrogel for Pb, Cu and Cd reached up to 434.89, 115.30 and 102.38 mg·g, respectively, better than those of other physical hydrogels or chitosan/bentonite composite. Moreover, the composite hydrogel improved the collectability of bentonite and showed a good reusability. The modification of bentonite and the formation of hydrogel were completed simultaneously, which greatly simplifies the operation process compared with the prior similar works. These suggest that the CTS/CA/BT composite hydrogel has promising application prospects for removal of heavy metal ions from water.
为避免化学水凝胶吸附剂伴随的化学交联剂有毒残留物的二次污染，提高物理水凝胶的吸附性能，构建了壳聚糖/海藻酸钙/膨润土（CTS/CA/BT）复合物理水凝胶。通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）和扫描电子显微镜（SEM）确定了复合水凝胶的形成机理和结构。研究了该水凝胶在不同条件下对水中铅、铜和镉的吸附性能以及多离子竞争吸附情况。用标准吸附动力学和等温线模型描述了吸附过程。通过X射线光电子能谱（XPS）分析和吸附热力学分析发现，吸附为自发的物理化学吸附。结果表明，该水凝胶对铅、铜和镉的最大吸附容量分别达到434.89、115.30和102.38 mg·g，优于其他物理水凝胶或壳聚糖/膨润土复合材料。此外，复合水凝胶提高了膨润土的可收集性，并表现出良好的可重复使用性。膨润土的改性和水凝胶的形成同时完成，与以往类似工作相比，大大简化了操作过程。这些表明CTS/CA/BT复合水凝胶在去除水中重金属离子方面具有广阔的应用前景。
