AC/TiO_2复合颗粒的低温制备及对TNT废水的降解

Preparation of AC/TiO_2 Composite Particles at Low Temperature and its Application in Degradation of TNT Wastewater

以钛酸丁酯为原料,在80℃下通过溶胶-回流法在活性炭(AC)表面制备纳米TiO2,利用FE-SEM比较了制备过程中加入植酸、苯并三氮唑(BTA)或SnCl4对复合颗粒表面形貌的影响,结果表明粒径为20～30nm的TiO2颗粒附着在AC表面形成了AC/TiO2复合颗粒,加入植酸的复合颗粒表面呈海绵状,加入BTA后表面的TiO2变得更细小。三种样品表面Ti元素的XPS分析显示Ti 2p3/2和Ti 2p1/2两个峰间的能量差约为5.7eV,表明所制备的TiO2纯度较高;空载试验所获得TiO2样品的Raman光谱表明AC表面的TiO2为锐钛矿相;以TNT溶液为目标降解物,研究了三种复合颗粒的吸附性能和光催化性能,结果表明,添加植酸、苯并三氮唑(BTA)复合颗粒的吸附性能略高于活性炭原始样品;三种样品在紫外光照射下对TNT的降解效率均高于活性炭原始样品,TNT的降解率达到99.3%,分析认为AC和TiO2的复合协同效应有效提高了对TNT废水的降解能力。

AC/TiO2 composite particles were prepared by peptization-reflux method using Ti（OBu）4 as raw material, and three kinds of samples were obtained by adding phytic acid, BTA and SnCl4. FE-SEM observation shows the surface of AC is closely coated by TiO2 about 20 -30 nm in size. Spongy TiO2 coatings were obtained when phytic acid was added, while finer TiO2 particles were formed on samples with the addition ofBTA. XPS of Ti element in three kinds of samples show that the difference in binding energy of Ti 2p3/2 and Ti 2p1/2 is about 5.7 eV, indicating the purity of TiO2 on the surfaces of AC is high. Ramman spectra of TiO2 particles prepared by blank experiment without AC show that TiO2 particles are anatase. The photo-catalytic activity and absorptive capability of composite particles are studied by using TNT waste water as target pollutant. The results show that the absorptive capability of composite particles with phytic acid or BTA is slightly higher than that of AC. All samples of AC/TiO2 have better UV photo-catalytic activity compared with AC, and for AC/TiO2 particles with BTA the degradation of the TNT reached 99.3%, which was attributed to the synergistc effect of AC and TiO2.