| Titanium dioxide is the most preferable photocatalyst that widely used in antimicrobial, deodorization, air and water purification due to its high photo chemist ability, strong oxidizing power, stable chemical property, low cost and non-toxicity. However, the photocatalytic efficiency of TiO2 is hampered by the main drawback of its relatively lower solar energy utilization, higher carrier recombination rate and hardly utilized repeatedly. So TiO2 is limited in the industrial application. Doped and loaded modification can solve these problems. Doped modification can extend the response range of TiO2 to the visible region. Furthermore, it is benefit for the separation of photoelectron and photohole. Loaded modification can avoid reunion to facilitate the recovery. Doped modification prevents the aggregation of TiO2 particles, thus they are easily to recycle. In this paper, modified TiO2 was loaded on ACF. The photocatalytic performance and reusability of catalyst were investigated under simulated sunlight. The main contents and conclusions are as follows:1. ACF was prepared by the viscose-based nonwoven fabric and activated in phosphoric acid. The adsorption properties and the yield rate of the ACF were tested. The results show that the optimum preparation conditions are phosphoric acid concentration of 40%, impregnation time for 16h, calcination temperature at 450℃ and calcination time for 100 min. Under the best preparation conditions, the adsorption capacity of ACF for methylene blue is 239.2mg/L and the yield rate of ACF is 39.4%. It is found that the weight amount of influence to the adsorption properties of ACF is C(calcination temperature)>B(impregnation time)>D(calcination time)>A(phosphoric acid concentration)2. The viscose-based nonwoven fabrics were dipped in the N-doped, Ni-doped and N, Ni codeped TiO2 sol respectively, Then they are activated in phosphoric acid and calcined in a muffle furnace, and finally the doped TiO2/ACF were obtained.This photocatalysts were studied by XRD, SEM, FT-IR and UV-Vis DRS. The photocatalysts are well formed, and they have a clear spatial structure. Doped TiO2 were coated on the surface of ACF with low aggregation and superior dispersing ability. Rutile type TiO2 and anatase type TiO2 existe in all photocatalytic materials with small particle size. The viscose based ACF is successfully prepared with phosphoric acid activation. Moreover, the addition of N and Ni makes the sinergetic effets, wich shifted the absorption regions of TiO2 to visible light and enhanced the quantum efficiency.3. The N-doped TiO2/ACF were preparaed. The effects of experimental conditions on N-doped TiO2/ACF were investigated, which involved the addition ratio of N, calcination temperature, dippind times and using times. The content of N has a great influence on the photocatalytic activity and the optimum value is 0.5. The results showed that the decolorization rates of methylene blue solution increase at first and then decrease with the increase of calcination temperature. The decolorization rates of methylene blue solution also increase at first and then decrease with increase of the dipping times. The optimum preparation conditions are N doping content of 0.5, dipping 3 times and calcined at 500℃. The degradation rate of methylene blue solution is higher than 90% when N0.5 Ti2/ACF-500 is reused three times.4. The N, Ni codoped TiO2/ACF were preparaed and their photocatalytic performance were studied. The results show that the photocatalyst with best decolorization rate of methylene blue solution is that N doping amount is 0.5, Ni content is 0.01, dipping time is 3 and calcination temperature is 500℃. the decolorization rate is 96.2% under simulated sunlight irradiation for 1 h. The decolorization rate of methylene blue solution is still higher than 90% after reusing 5 times with N0.5Ni0.01TiO2/ACF-3. This result is mainly due to the excellent photocatalytic performance of N0.5Ni0.01TiO2/ACF-3. |
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