Research On Degradation Of Gaseous Toluene With Catalytic Oxidation

Along with the environmental pollution is becoming increasingly extrude, people pay more and more attention to the air quality problem.Then volatile organic compounds(VOCs) is used numerously and extensively by people,which makes its residues existing in the water, soil and air. Most of VOCs are poisonous,Some of these can bring illness and carcinogenic or teratogenesis.Currently,the common techniques of disposing VOCs contain adsorption method, absorption method, condensation method and combustion method and etc,Although these methods could dispose VOCs very well,but there also exist a number of shortage.Then,photocatalytic degradation can decompose almost all the organic compounds moderaly and facilitiy,and the final product ususlly are just CO2 and H2O.Therefore, photocatalysis technology come in for importance all country in the world because of its character of highly active, profundity degreduation and no secondary pollution, and being a efficiency measure of dealing with VOCs in the air.This text is about to adopt the foam nickel board of loading the Nano-TiO2 prepared by Sol-gel method as Photocatalyst useing self-made batch-photocatalytic reactor,and study on TiO2 photocatalytic degradation toluene,benzene and xylene,meantime review the effects of velocity of TiO2 photocatalytic degradation toluene by these environmental elements,such as lighe-sourse, Initial concentration,catalyzer area,humidity and oxygen content,in order to find out its optimum condition;Then,it also compare photodegradation with photocatalytic degradation effect of toluene,benzene and xylene,and take a test on the inactivation and regeneration of photocatalyst.The results of these test indicate that the each adsorption equilibrium time of benzene and toluene and xylene is 40min,40min and 50min; Photoeatalytic degradation efficience of toluene by foamed nickel board coated with nano-TiO2 rapidly rise in the beginning,and since the reation happened 600min, the photoeatalytic degradation efficiency was up to 89.1% slownessly,then gone to invariant;While the initial concentration of toluene is 52 mg/m3,its degradation efficiency reach to the maximum; On the contrary, the photoeatalytic degradation efficiency will drop down 81.2%,when initial concentration of toluene rise to 104mg/m3; When the humidity is at the range of 25%～65%,along with the increase of the humidity, photoeatalytic degradation efficience of toluene also reach to the maximum being 89.7%,so optimum humidity of the test is 65%; In a similar way,when oxygen content is at the range of 5%～21%,along with the increase of oxygen content photoeatalytic degradation efficience of toluene also reach to the maximum,so optimum oxygen content of the test is 21%,namely being at standard air condition; When turnning on the both of light in 185nm and 254nm, photoeatalytic degradation efficience of toluene is better than the other combine formal; Along with the increase of the area of the foam nickel net, photoeatalytic degradation efficience of toluene also rise up,it means that the catalyzer content and illumination area with photoeatalytic degradation efficience is pro rata changed; Photoeatalytic degradation efficience of foamed nickel board coated with nano-TiO2 catalyzer with reacting 96h is lowered almost 30% than the sample with reacting 24h;Meanwhile,after ultraviolet irradiation of 3h,the sample's activity recovered 70%,and its activity will recover completely when the time extend to 12h.