| It has been deeply studied on the treatment of organic pollutants in wastewater by semiconductor photocatalytic degradation. The pollutants can be entirely broken down to intoxious matters by photocatalytic degradation which can be finished at normal temperature and pressure in short time, so photocatalysis method has become one of the most effective methods to degrade vary kinds of pollutants. Titanium dioxide has become an important and developing photocatalyst for its higher stability and activity, cheapness, intoxicity, difficulty to dissolve in the acid and alkali conditions. However, usual suspension photocatalysis oxidation had some disadvantages, such as inclination to inactivate and agglomerate, difficulty to reuse and easiness to cause the second pollution. These shortcomings seriously limited the application of titanium dioxide. So researchers focused the emphases on the syntheses of the immobilized photocatalyst that could enhance its photocatalytic activity.This paper prepared titanium dioxide photocatalyst supported on a natural zeolite (Jiutai of Jilin Province)with tetrabutyl titanate as titanium source. The chemical combination was achieved between titanium dioxide and the mineral. Good combination between the mineral and the anatase overcomed the disadvantages of titanium dioxide such as difficulty to reuse and easiness to cause the second pollution ,As a result, the composite titanium dioxide had a better applying foreground than the suspension of pure titanium dioxide .In this paper, we discussed the optimize conditions of synthesize and influence factors of its activity, methylorange was taken as aim pollutant, ultraviolet (λ=365nm) and sunlight as light source. The TiO2/zeolite photocatalyst was obtained by the load of titanium dioxide sol synthesized by acid-catalyzed sol-gel method on natural zeolite. The experimental results showed that titanium dioxide supported on natural zeolite treated at 200℃ had the best photocatalytic activity. Structure test showed it was anatase that had the best crystallization and the biggest content. The synthesized titanium dioxide supported on a natural zeolite transformed from anatase to rutile gradually with the calcining temperature increasing . the composite has a higher photocatalytic activity because the electron and hole were produced easier for anatase than that of rutile to photocatalytic degradation. It also showed that methylorange could be easily decomposed at acid conditions and could be broken down at pH2.0-pH5.0. There was no obvious difference in the degradation rate at the initial pH of 2.0-5.0, and the final pH value of reaction solutions were around 7.0 in the study. Adaptable addition of additional oxidiation such as hydrogen peroxide may accelerate the velocity of photodegrading for it acted as electron acceptor which may inhibit the recombination of electron and hole ,producing more ·OH on the surface of titanium dioxide; With the increasing of composite photocatalyst, the decolored rate of methylorange increase, but only a litte enhanced after the photocatalyst content reached 1.5g/100mL; The structure and the size of support zeolite affected the activity of photocatalyst strongly, the smaller size of the support, the higher activity, this may be attributed to the larger specific area of the composite,however the smaller size of the support may bring difficulty to reuse and cause a second pollution, So adaptable size of the support between 40 and 100 mesh was necessary. Other factors such as the ultraviolet strength, radiatation on the composite photocatalyst with ultraviolet before use, vision light's effect on the photodegrading activity etc. were also discussed in detail in our paper. Photodegrading kinetics curves of methyl-orange with supported TiO2 as catalyst followed quasi-first-order equation. At lower initial concentration photodegradation rate was positive related to initial concentration of methyl-orange. Photodegration reaction inclined to first-order reaction at lower content and inclined to z...
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