Evaluations of physico-chemical properties of TiO2/clinoptilolite synthesized via three methods on photocatalytic degradation of crystal violet

Different preparation routes for TiO2-supported natural and synthetic clinoptilolite (TiO2/CP) composites were thoroughly investigated on the basis of sol–gel, hydrothermal, and in-situ hydrothermal methods. The micro-structural features and physicochemical properties of resultant TiO2/CPs were characterized via X-ray diffraction patterns, scanning (transmission) electron microscope images, Fourier transform infrared spectra, inductively coupled plasma-optical emission spectrometry methods, BET-isotherms, UV–visible spectra, and surface charge potential distributions. The results showed that in-situ hydrother-mal method led to well dispersions of loaded-TiO2 particles on the surface of leaf-like CP, while obviously aggregated TiO2 on a relatively distorted structure of CP was obtained using sol–gel and hydrothermal methods. Their adsorptive and photocatalytic efficiencies for removal of crystal violet (CV) dye in aque-ous solution were also explored under UV-irradiations. The results demonstrated that TiO2/CPs synthe-sized via sol–gel and in-situ hydrothermal methods presented the excellent performances with 98％removal efficiencies as compare to the bare commercial TiO2 which achieved 53％ removal of CV dye. While, the in-situ hydrothermally synthesized TiO2/CPs were the best due to their moderate energy cost, highest adsorption capacities and removal efficiencies. Particularly, the synthetic CPs as supports exhib-ited synergetic photocatalytic activities for the degradation of CV dye, which is attributed to their high surface areas, better adsorption capability, and fine dispersion of TiO2 particles. Adsorption and degrada-tion kinetics of CV dye were found to follow the pseudo-second and pseudo-first order models, respectively.