Guo Xuebai, Wu Zhenjun, Wang Zelong, Lin Fangfang, Li Penghui, Liu Jiaxin
Henan Vocational College of Water Conservancy and Environment, Zhengzhou 450008, China.
School of Environmental Engineering, Henan University of Technology, Zhengzhou 450001, China.
ACS Omega. 2023 May 21;8(22):19455-19463. doi: 10.1021/acsomega.3c00745. eCollection 2023 Jun 6.
In this study, chitosan-modified bentonite was synthesized using the coprecipitation method. When the NaCO content was 4% (weight of soil) and the mass ratio of chitosan to bentonite was 1:5, the adsorption performance of the chitosan/bentonite composite was best. The adsorbent was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller measurement. Various characterization results demonstrate that chitosan successfully entered the bentonite interlayer and increased layer spacing but did not modify bentonite's laminar mesoporous structure, and the -CH and -CH groups of chitosan appeared on chitosan-modified bentonite. Tetracycline was used as the target pollutant in the static adsorption experiment. The adsorption capacity was 19.32 mg/g under optimal conditions. The adsorption process was more consistent with the Freundlich model and the pseudo-second-order kinetic model, indicating that it was a nonmonolayer chemisorption process. The adsorption process is a spontaneous, endothermic, entropy-increasing process, according to thermodynamic characteristics.
在本研究中，采用共沉淀法合成了壳聚糖改性膨润土。当碳酸钠含量为4%（土壤重量）且壳聚糖与膨润土的质量比为1:5时，壳聚糖/膨润土复合材料的吸附性能最佳。通过扫描电子显微镜、X射线衍射、傅里叶变换红外光谱和布鲁诺尔-埃米特-泰勒测量对吸附剂进行了表征。各种表征结果表明，壳聚糖成功进入膨润土的层间并增加了层间距，但未改变膨润土的层状介孔结构，且壳聚糖改性膨润土上出现了壳聚糖的-CH和-CH基团。在静态吸附实验中，四环素用作目标污染物。在最佳条件下，吸附容量为19.32 mg/g。吸附过程更符合弗伦德利希模型和伪二级动力学模型，表明这是一个非单层化学吸附过程。根据热力学特征，吸附过程是一个自发、吸热、熵增加的过程。
