TiO_2-海藻酸钙复合膜的表征、对染料的光催化降解及TiO_2回收

Characterization and dyes photocatalytic degradation of TiO_2-calcium alginate composite films and recycle of TiO_2

为了解决TiO2纳米粒子难分离,负载的催化剂难回收等问题,首先,将TiO2与海藻酸钠充分混合制成铸膜液,在玻璃板上刮膜,经钙离子交联制备了TiO2-海藻酸钙(T-CA)复合膜。然后,对T-CA复合膜进行了SEM和XRD表征,并研究了T-CA复合膜对染料的光催化降解性能。最后,将T-CA复合膜从染料降解液中取出,浸泡在柠檬酸钠水溶液中,柠檬酸根对钙离子的结合力较强,可使海藻酸盐水凝胶溶解,离心分离TiO2纳米粒子并清洗干燥后,得到了回收TiO2;利用SEM、TEM、FTIR和XRD对回收TiO2进行了表征。结果表明:T-CA复合膜对甲基橙的光催化降解率可达82.37%。回收TiO2与初始的TiO2几乎完全一样,可重新使用且催化能力不变。该方法是一种绿色环保、方便快速的从载体中回收TiO2纳米粒子的方法。

In order to deal with the problems that TiO2 nanoparticles were difficult to be separated and the supported catalysts were difficult to be recycled,first,TiO2 and sodium alginate were blended together to prepare the casting solution,and then outspread on a glass plate.TiO2-calcium alginate(T-CA)composite films were prepared by cross-linking with calcium ion.Second,the T-CA composite films were characterized by SEM and XRD.The photocatalytic degradation of T-CA composite films for dyes was also investigated.Finally,T-CA composite films were taken out from degradation liquid of dyes,and soaked in sodium citrate aqueous solution.The binding force of citrate towards calcium ion was stronger,thus made the alginate hydrogel dissolved.After centrifugal separation of TiO2 nanoparticles,cleaning and drying,the recycled TiO2 was obtained.SEM,TEM,FTIR and XRD were used to characterize the recycled TiO2.The results show that the degradation ratio of T-CA composite films for methyl orange reaches 82.37%.The recycled TiO2 are almost exactly the same as the original TiO2,which can be used again and the catalytic ability almost constant.So the method is an environmental-friendly,convenient and efficient method for recycling TiO2 nanoparticle from supporters.