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

Highlights: ► The reconstructed organic LDHs are consisted of the interconnecting nano-flakes. ► It is confirmed that organic LDHs/TiO2 composites are combined together by chemical bonds. ► The organic LDHs with flaky structure effectively enrich DPM onto the composite. ► The abundant external hydroxyl groups of organic LDHs promote the production of ·OH. ► TiO2 immobilized onto organic LDHs greatly enhances the photodegradation of DMP. -- Abstract: The organic layered double hydroxides (LHDs)/TiO2 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 TiO2 particles and the organic LDHs were combined together through chemical bonds, and TiO2 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