氮掺杂纤维素基碳气凝胶对染料吸附的影响

Effect of N-doped Cellulose Based Carbon Aerogel on Dye Adsorption

关键词:  氮掺杂  纤维素  碳气凝胶  选择性吸附

Key Words:N-doped  cellulose  carbon aerogel  selective adsorption

摘要:采用尿素改性与冷冻干燥法相结合的方式制备了可循环使用的氮掺杂纤维素基气凝胶，并对该气凝胶进行碳化得到氮掺杂纤维素基碳气凝胶（N-CCA）。分析了N-CCA的形貌和结构特征，并对废水中阳离子染料亚甲基蓝（MB）和阴离子染料刚果红（CR）的吸附性能进行了研究。SEM、XRD、氮气吸附脱附仪测试结果表明，经过尿素改性后，纤维素基碳气凝胶形貌发生重组，孔隙结构更加紧密，石墨化程度降低，比表面积增加，有利于提高染料去除能力。通过紫外可见分光光度计测试表明，改性后的N-CCA对阳离子染料MB的吸附能力略微下降，但对阴离子染料CR的吸附能力提升明显，从改性之前的87.12 mg/g增加到360.63 mg/g。N-CCA材料具有选择性吸附性解，循环使用5次，CR去除率保持在98%以上。

Abstract:The low-cost and renewable N-doped cellulose based aerogels were prepared using the methods combining urea modification and freeze drying, which further underwent a carbonization process could obtain N-doped cellulose based carbon aerogels (N-CCA). Morphology and structural characteristics of the N-CCA were examined, and its adsorption performances on cationic dyes methylene blue (MB) and anionic dyes congo red (CR) from wastewater were investigated. SEM, XRD and BET test results showed that the morphology of N-CCA was reconstituted, the pore structure was closer, the graphitization degree was reduced, and the specific surface area was increased, all of which would be beneficial to improve the dye removal ability. The UV-visible spectrophotometer test showed that the adsorption capacity of N-CCA to cationic dye MB decreased slightly, but the adsorption capacity to anionic dye CR increased significantly, from 87.12 mg/g before modification to 360.63 mg/g.