Abstract: The porous natural zeolites have been employed as the TiO₂ supports, and the photocatalytic process of TiO₂/zeolite on methyl orange (MO) has been studied. The interface mechanism between the TiO₂ and the natural zeolite has been discussed, and the change of the kinetic process before and after TiO₂ loading has been studied for the first time. The “super reaction area” model has been brought out for liquid system, in order to explain the photocatalytic process of the TiO₂/zeolite system. The AFM, IR and spectra analysis, a certain amount of TiO₂ combined with natural zeolite by Ti-O-Si or Ti-O-Al chemical bond. At the initial stage of photcatalytic degradation (PCD) of MO, the addition of nature zeolite supports have made the initial reaction change from original poor “adsorption controlled” process to the “reaction controlled” process. Since all of the reaction rates of TiO₂/zeolite are higher than the pure TiO₂ powder, it’s obvious that the zeolite supports have enhanced the rate of the slower adsorption process resulting in the increase of the initial reaction rate R₀. The firstorder reaction rate k₁ shows that no matter what kind of process controlled the PCD process at the initial stage the whole process of PCD must be an adsorption controlling process undoubtedly because of the proliferating of the medial product.

Key words: natural zeolite, TiO₂, photocatalysis, interaction mechanism