Enhancement of photocatalytic degradation of dimethyl phthalate with nano-TiO2 immobilized onto hydrophobic layered double hydroxides: a mechanism study.

The organic layered double hydroxides (LHDs)/TiO(2) composites with various mass ratios were prepared by the reconstruction of mixed metal oxides to photodegrade dimethyl phthalate (DMP). The physicochemical properties of the obtained products were analyzed by X-ray diffraction (XRD) spectra, X-ray photoelectron spectra (XPS), UV-vis diffuse reflectance spectroscope and scanning electron microscope (SEM). The results showed that the TiO(2) particles and the organic LDHs were combined together through chemical bonds, and TiO(2) particles were well distributed on the surface of the interconnecting organic LDHs nano-flakes. According to the experimental results of adsorptive and photodegradation of DMP, the organic LDHs with flaky structure could effectively adsorb the DMP molecules and the adsorption isotherm by the composites modeled well with the Langmuir equation. The enrichment of DMP onto the composites and the external hydroxyl groups of the composites produce a synergistic effect leading to greatly enhance the rate of DMP photocatalytic degradation by the obtained composites.