TiO_2/蒙脱土复合材料的制备及光催化降解苯酚性能

为了利用TiO_2优越的光催化活性和蒙脱土(MMT)的结构特性,首先,以MMT为载体、TiCl_4为原料、氨水为沉淀剂,采用水解沉淀法制备了TiO_2/MMT复合材料;然后,利用FTIR、XRD和SEM对TiO_2/MMT复合材料进行成分、晶型、结构和形貌表征;最后,在紫外光照射下,考察了不同TiO_2含量的TiO_2/MMT复合材料对模拟苯酚废水的光催化降解活性,并结合紫外-可见光谱对复合材料光催化降解苯酚的过程进行了跟踪实验。结果表明:所制备的TiO_2/MMT复合材料中TiO_2为锐钛矿相,在MMT上的晶粒尺寸为7.8nm。TiO_2/MMT复合材料中层间域内成分被钛柱取代,且柱撑反应在层间域内进行。因此MMT的基本骨架不变,且TiO_2分散在MMT的表面。当苯酚的初始浓度为10mg/L、苯酚溶液的pH为6且紫外光照射时间为150min时,37.5wt%TiO_2/MMT复合材料对苯酚降解率为63%,优于MMT(4.5%)和纯TiO_2(55%),说明MMT的负载提高了TiO_2的光催化活性。

Preparation and photocatalysis degradation performances for phenol of TiO2/montmorillonite composites

In order to make use of the superior photocatalytic activity of TiO₂ and the structural properties of montmorillonite (MMT), TiO₂/MMT composites were fabricated by hydrolysis precipitation method using MMT as carrier, TiCl₄ as raw material and ammonium hydroxide as precipitant firstly. Then, the component, crystal form, structure and morphology were characterized by FTIR, XRD and SEM. Finally, under the irradiation of ultraviolet light, the photocatalysis degradation activity of TiO₂/MMT composites with different TiO₂ contents for simulation phenol waste water were investigated, and the tracking experiments were conducted for the process of phenol photocatalysis degradation by composites combined with ultraviolet-visible spectra. The results illustrate that TiO₂ in the prepared TiO₂/MMT composites is anatase phase, and the crystallite dimension on MMT is 7.8 nm. The domain components of interlayer in TiO₂/MMT composites are replaced by titanium pillars, and the pillared reaction processes in the interlayer regions. Thus the basic frame of MMT does not change, and TiO₂ spreads on the surfaces of MMT. When the initial concentration of phenol is 10 mg/L, the pH of phenol solution is 6 and the ultraviolet irradiation time is 150 min, the degradation rate of 37.5wt% TiO₂/MMT composites for phenol is 63%, superior than that of MMT (4.5%) and pure TiO₂ (55%), displays that the loading of MMT improves the photocatalytic activity of TiO₂.