壳聚糖改性提高沸石分子筛吸附诺氟沙星性能研究

Research on chitosan modification to improve the performance of norfloxacin adsorption by zeolite molecular sieve

利用壳聚糖对沸石分子筛进行改性,分别对改性前后的吸附剂进行电子显微镜(SEM)和BET表征,优化壳聚糖改性前后的沸石分子筛对诺氟沙星的吸附工艺并比较吸附效果,探究壳聚糖改性沸石分子筛及沸石分子筛对诺氟沙星的动力学和等温吸附特征以及壳聚糖改性沸石分子筛的再生性能。结果表明:与未改性的沸石分子筛相比,壳聚糖负载于沸石分子筛的表面和孔道内,增加了吸附位点,比表面积提高80.94%。最佳吸附条件下,壳聚糖改性沸石分子筛对诺氟沙星的去除率为88.16%,未改性的沸石分子筛对诺氟沙星的去除率仅为34.28%,壳聚糖改性后的吸附效果显著提升。两种吸附剂对诺氟沙星的吸附动力学均符合准二级动力学方程,吸附等温线符合Langmuir模型。壳聚糖改性沸石分子筛具有较好的可再生性,可重复利用,且不易产生二次污染。

The zeolite molecular sieve was modified by chitosan, and the adsorbents before and after the modification were characterized by SEM and BET respectively. The adsorption process of norfloxacin on the zeolite molecular sieve before and after modification with chitosan was optimized and the adsorption effect was compared. The kinetic and isothermal adsorption characteristics of the chitosan-modified zeolite molecular sieve and zeolite molecular sieve on norfloxacin were investigated and regenerative properties of chitosan-modified zeolite molecular sieve were studied. The results showed that the loading of chitosan on the surface and within the pore channels of zeolite molecular sieve increased the adsorption sites and increased the specific surface area by 80.94% compared to the unmodified zeolite molecular sieve. The removal rate of norfloxacin by chitosan-modified zeolite molecular sieve was 88.16% under the optimal adsorption conditions, while the removal rate of norfloxacin by unmodified zeolite molecular sieve was only 34.28%, and the effect of chitosan modification was significant. The adsorption kinetics of both adsorbents on norfloxacin were followed the quasi-secondary kinetic equation, and the adsorption isotherms were in accordance with the Langmuir model. Chitosan-modified zeolite molecular sieve has good reproducibility and can be reused, and is less likely to produce secondary pollution.