TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

摘要

In this study photocatalyst, TiO2@HNTs were prepared by synthesizing TiO2 nanoparticles in situon the functionalized halloysite nanotubes (HNTs) surface. Photocatalytic PVC membrane TiO2@HNTs M2 (2wt.%) and TiO2@HNTs M3 (3wt.%) were also prepared. Photocatalyst TiO2@HNTsand photocatalytic PVC membranes were used to study the photocatalytic activity against themethylene blue (MB) and rhodamine B (RB) dyes in UV batch reactor. The structure and morphologyof photocatalyst and photocatalytic PVC membrane were characterized by fourier transforminfrared spectroscopy (FT-IR), X-ray difraction (XRD), scanning electron microscopy (SEM), energydispersive X-ray (EDX), transmission electron microscopy (TEM), UV-Vis spectrophotometer andphotoluminescence (PL). The PL study showed that the oxygen vacancies and surface hydroxyl groupspresent on the surface of TiO2@HNTs act as excellent traps for charge carrier, reducing the electronholerecombination rate.TiO2@HNTs 2 (2wt.%) and TiO2@HNTs 3 (3wt.%) degraded MB dye up to83.21%, 87.47% and RB dye up to 96.84% and 96.87%, respectively. TiO2@HNT photocatalyst provedto be stable during the three consecutive cycle of photocatalytic degradation of the RB dye. TiO2@HNTs M2 and TiO2@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 frst-order kineticmodel. 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 themolecule. MB and RB dye degradation reaction were tested by TBA and IPA as OH* and H+ scavengersrespectively. Mechanism of photocatalytic activity of TiO2@HNTs and photocatalytic PVC membranewere also explained.