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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 solve the problem of difficult separation of TiO2 nanoparticles and difficult loading of supported catalyst, first, titanium dioxide and sodium alginate are thoroughly mixed to prepare a casting solution, and a film is formed on a glass plate to prepare TiO2-alginic acid by calcium ion crosslinking Calcium (T-CA) composite membrane. Then, the T-CA composite films were characterized by SEM and XRD, and the photocatalytic degradation of T-CA composite films was studied. Finally, the T-CA composite membrane was removed from the dye degradation solution and soaked in an aqueous solution of sodium citrate. The binding ability of citrate to calcium ions was strong, which allowed the alginate hydrogel to dissolve and centrifuge the TiO2 nanoparticles After washing and drying, the TiO2 was recovered. The recovery of TiO2 was characterized by SEM, TEM, FTIR and XRD. The results showed that the photocatalytic degradation rate of methyl orange by T-CA composite membrane was up to 82.37%. The recovery of TiO2 is almost exactly the same as the initial TiO2, reusable and has the same catalytic capacity. The method is a green and convenient and rapid method for recovering TiO2 nano-particles from a carrier.