Mishra Gourav, Mukhopadhyay Mausumi
Department of Chemical Engineering, Sardar Vallabhbhai National Institute of Technology Surat, Gujarat, India.
Sci Rep. 2019 Mar 13;9(1):4345. doi: 10.1038/s41598-019-40775-4.
In this study photocatalyst, TiO@HNTs were prepared by synthesizing TiO nanoparticles in situ on the functionalized halloysite nanotubes (HNTs) surface. Photocatalytic PVC membrane TiO@HNTs M2 (2 wt.%) and TiO@HNTs M3 (3 wt.%) were also prepared. Photocatalyst TiO@HNTs and photocatalytic PVC membranes were used to study the photocatalytic activity against the methylene blue (MB) and rhodamine B (RB) dyes in UV batch reactor. The structure and morphology of photocatalyst and photocatalytic PVC membrane were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), UV-Vis spectrophotometer and photoluminescence (PL). The PL study showed that the oxygen vacancies and surface hydroxyl groups present on the surface of TiO@HNTs act as excellent traps for charge carrier, reducing the electron-hole recombination rate.TiO@HNTs 2 (2 wt.%) and TiO@HNTs 3 (3 wt.%) degraded MB dye up to 83.21%, 87.47% and RB dye up to 96.84% and 96.87%, respectively. TiO@HNT photocatalyst proved to be stable during the three consecutive cycle of photocatalytic degradation of the RB dye. TiO@HNTs M2 and TiO@HNTs M3 degraded MB dye up to 27.19%, 42.37% and RB dye up to 30.78%, 32.76%, respectively. Photocatalytic degradation of both the dyes followed the first-order kinetic model. Degradation product analysis was done using the liquid chromatography-mass spectrometry (LC-MS) and the results showed that the dye degradation was initiated by demethylation of the molecule. MB and RB dye degradation reaction were tested by TBA and IPA as OH and H scavengers respectively. Mechanism of photocatalytic activity of TiO@HNTs and photocatalytic PVC membrane were also explained.
在本研究中，通过在功能化埃洛石纳米管（HNTs）表面原位合成TiO纳米颗粒来制备光催化剂TiO@HNTs。还制备了光催化PVC膜TiO@HNTs M2（2 wt.%）和TiO@HNTs M3（3 wt.%）。在紫外间歇反应器中，使用光催化剂TiO@HNTs和光催化PVC膜研究对亚甲基蓝（MB）和罗丹明B（RB）染料的光催化活性。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、能量色散X射线（EDX）、透射电子显微镜（TEM）、紫外可见分光光度计和光致发光（PL）对光催化剂和光催化PVC膜的结构和形貌进行了表征。PL研究表明，TiO@HNTs表面存在的氧空位和表面羟基作为电荷载流子的优良陷阱，降低了电子-空穴复合率。TiO@HNTs 2（2 wt.%）和TiO@HNTs 3（3 wt.%）分别将MB染料降解高达83.21%、87.47%，将RB染料降解高达96.84%和96.87%。TiO@HNT光催化剂在RB染料的连续三个光催化降解循环中被证明是稳定的。TiO@HNTs M2和TiO@HNTs M3分别将MB染料降解高达27.19%、42.37%，将RB染料降解高达30.78%、32.76%。两种染料的光催化降解均遵循一级动力学模型。使用液相色谱-质谱联用仪（LC-MS）进行降解产物分析，结果表明染料降解是由分子的脱甲基作用引发的。分别用TBA和IPA作为OH和H清除剂测试了MB和RB染料的降解反应。还解释了TiO@HNTs和光催化PVC膜的光催化活性机理。
