纤维素基碳复合气凝胶的制备及其光催化性能研究

Preparation and photocatalytic properties of cellulose based carbon composite aerogels

光催化法治理水污染因具有绿色环保、高效和净化彻底等优点而受到研究者的关注,然而,粉末催化剂难以回收利用阻碍了其在实际应用中的推广.为了解决以上问题,基于多孔石墨相氮化碳(g-C_(3)N_(4))和纤维素气凝胶的优点,本研究将溶胶-凝胶法与高温炭化工艺相结合,制备得到了一种三维多孔复合气凝胶(CN_(x)/CA).经碳化处理后,多孔g-C_(3)N_(4)均匀牢固地结合在纤维素碳气凝胶表面.当多孔g-C_(3)N_(4)的添加量为1 g时,得到的复合气凝胶具有较好的光催化性能.在光反应进行180 min时,对四环素的降解率达到92%.根据紫外可见漫反射及光致发光光谱可知,CN_(x)/CA的催化性能的提高主要源于其具有优异的光吸收能力及更低的载流子复合率,并且通过电子顺磁共振测试结果显示,光催化降解的主要活性物种是超氧自由基.

Photocatalytic treatment of water pollution has attracted the attention of researchers because of its advantages of eco-friendly,high efficiency and thorough purification,however,the difficulty in recycle of catalyst powders,hinders its application in practice.In order to solve the above problems,three-dimensional porous composite aerogel(CN_(x)/CA)was proposed by integrating sol-gel method with high-temperature carbonization process based on the advantages of porous graphite phase carbon nitride(g-C_(3)N_(4))and cellulose aerogel.After carbonization treatment,porous g-C_(3)N_(4)was uniformly and firmly bound on the surface cellulose carbon aerogels.When the amount of porous g-C_(3)N_(4)was 1 g,the composite aerogels displayed good photocatalytic performance.The degradation rate of tetracycline(TC)reached 92%after 180 min of photoreaction.The improved catalytic performance of CN_(x)/CA was mainly due to its excellent light absorption capacity and faster carrier migration.The results of electron paramagnetic resonance(EPR)test showed that the main active species during photocatalytic degradation is superoxide free radicals.