纤维素/壳聚糖磁性气凝胶的冻融法制备及其对染料吸附性能

Adsorption performance of cellulose/chitosan magnetic aerogel prepared by freeze-thawing method

为开发一种高效可再生的磁性生物质基吸附剂,以微晶纤维素(MCC)和壳聚糖(CS)为凝胶网络框架、纳米Fe_(3)O_(4)为掺杂剂,通过悬浮液滴和冻融结合法制备MCC/CS磁性气凝胶。借助扫描电子显微镜、傅里叶红外光谱、X射线衍射等表征其微观形貌及化学结构,并探讨了对染料刚果红的去除效果。结果表明:在加入1.0 g纳米Fe_(3)O_(4)时,MCC/CS磁性气凝胶呈现片层堆积的网络多孔结构,纳米Fe_(3)O_(4)分散均匀,气凝胶磁响应性能良好;当pH=5.0,染料初始质量浓度为400 mg/L,MCC/CS磁性气凝胶质量浓度为0.5 g/L时,吸附效果最佳,吸附过程遵循准二级动力学方程和Langmuir等温模型,最大单分子层吸附容量为304 mg/g;经过5次循环后,对刚果红的吸附量仍能保持86.5%,表明MCC/CS磁性气凝胶可作为一种高效可再生的生物质基吸附剂用于印染废水处理。

In order to develop an efficient and renewable magnetic biomass-based adsorbent,microcrystalline cellulose(MCC)/chitosan(CS)magnetic aerogel was synthesized via a combination method of floating droplet and freeze-thawing,in which MCC and CS worked as the network frameworks,and Fe_(3)O_(4) nanoparticles endowed the magnetic property.The morphology and chemistry performance of MCC/CS magnetic aerogel were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy and X-ray diffraction,and its removal performance for Congo Red was discussed.The results showed that when 1.0 g Fe_(3)O_(4) nanoparticles was incorporated,MCC/CS magnetic aerogel present a porous network structure with lamellar accumulation and good magnetic response with Fe_(3)O_(4) nanoparticles evenly distributed on the lamellar frames.The optimal adsorption conditions for Congo Red were found to be pH 5.0,dye initial concentration 400 mg/L and MCC/CS magnetic aerogel dosage 0.5 g/L.The adsorption process followed the pseudo-second order kinetics equation and Langmuir isotherm model,and the maximum monolayer adsorption capacity of MCC/CS magnetic aerogel for Congo Red was estimated to be 304 mg/g.The regeneration study demonstrated that the adsorption capacity retained about 86.5%of its initial level at the 5th sequential regeneration cycle,indicating that MCC/CS magnetic aerogel can be used as a high-efficient and renewable biomass-based adsorbent for dye wastewater treatment.