Ag_2O/再生纤维素球形气凝胶的性能表征

Performance Characterization of Ag_2O/Regenerated Cellulose Spherical Aerogel

为了探讨再生纤维素气凝胶对碘蒸气的吸附去除能力,用天然竹纤维制备再生纤维素球形气凝胶(RCSA),然后通过银氨络离子在纤维素表面的吸附和反应,得到Ag2O/再生纤维素球形复合气凝胶(Ag2O/RCSA),以127I作为放射性131I的同位素研究了复合气凝胶对碘的吸附。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和BET比表面积等检测手段对制备的Ag2O/RCSA样品的形貌、晶型、孔隙结构和碘吸附性能进行了表征。研究结果表明:纳米Ag2O粒子的引入使RCSA颜色由白色变为棕色,RCSA原始的三维网结构没有发生变化;纳米Ag2O粒子均匀分布在纤维素骨架中,并与纤维素紧密结合;Ag2O/RCSA与RCSA一样都表现为Ⅳ型吸附/脱附等温线,BET比表面积、BJH孔体积比RCSA明显减小,平均孔径大小变化不大;Ag2O/RCSA对碘蒸气的吸附是气凝胶孔隙的物理吸附和Ag2O转变为Ag I的化学吸附共同作用,总吸附量为87.8 mg/g。

In order to investigate the adsorption ability of regenerated cellulose aerogel to iodine vapor,regenerated cellulose spherical aerogels（RCSA） were prepared from natural bamboo fibers and then Ag2 O/RCSA were fabricated by adsorption and reaction of ammine silver complex ion on the surface of cellulose.In addition,the adsorption ability to iodine was studied by taking127 I as the radioisotope of131 I.The morphology,crystal form and pore structure of Ag2 O/RCSA were characterized and analyzed by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD） and BET specific surface area.The results showed that the color of RCSA turned from white to brown with the appending of Ag2 O nanoparticles,but the original three-dimensional network structure cellulose aerogels didn＇t change.Ag2 O nanoparticles uniformly distributed in the cellulose backbone and closely combined with cellulose.Both N2 adsorption and desorption isotherms of RCSA and Ag2 O/RCSA exhibited the characteristics of type Ⅳ isotherms.The BET specific surface area and BJH pore volume of Ag2 O/RCSA decreased obviously compared with those of RCSA,and there was little change in the size of the average pore diameter.The adsorption of Ag2 O/RCSA to iodine vapor was physical adsorption by porous aerogel and chemical adsorption by turning Ag2 O into Ag I,and the total iodine vapor adsorption capacity of Ag2 O/RCSA was 87.8 mg/g.