Preparation And Photocatalysis Property Of TiO₂/ACF Photocatalytic Material

Titanium dioxide(TiO₂) can produce the highly active hydroxyl radical when it is subjected by illumination.The hydroxyl radical can degrade which are adsorbed on the TiO₂ surface due to its strong oxidative. The organic matter or toxic inorganic oxide is degraded to CO₂, H2O and non-toxic inorganic components. However, TiO₂ is devitalize, essy agglomeration owned and difficult recycling when used in the present. So the immobilization of TiO₂ can solve these problems. Activated carbon fiber (ACF) has high specific surface area and good adsorption capacity. These provide high-concentration organic pollutants in the photocatalytic reaction for the catalyst, and catalyst can get a better dispersion. The interaction of vector and catalysts enhance the photocatalytic activity of TiO₂. ACF become the main carrier of TiO₂ becase of the synergistic effect of adsorption and photocatalytic degradation which will improve the photocatalytic efficiency.The thesis adopted orthogonal experiment to analyse the effect of kinds of factors on TiO₂ collosol and the stability of TiO₂ water dispersions, and relative stable TiO₂ collosol and TiO₂ water dispersions were prepared. It is found that the weight amount of effecting the stability of TiO₂ collosol is B (the volume of absolute ethanol >A(the volume rate of Ti(OC4H9)4 to H2O)>D(temperature)>C(the volume of ethanol), and the best factor level matching is A with 4,B with 25ml,C with 0.5ml and D with 27℃; The weight amount of effecting TiO₂ water dispersions is A (the concentration of SDBS) >C (the value of PH) >B(the concentration rate of SDBS to SHMP)>C(the volume of ethanol), and the best factor level matching is A with 0.3%,B with3,C with 9. TiO₂ collosol prepared in the best factor level condition can be steadily stored for 12 days. By particle size analysis it is found that the particle diameter of collosol is distributed in 100nm with most in several tens, and the particle size of collosol and its distribution are the key effecting the collosol stability. The zeta potential of prepared TiO₂ water dispersions is -49.80mv, and its particle size distribution is correspondingly concentrated with about 100nm particle diameter distribution and homogeneous particle size and distribution.Nano-TiO₂ was loaded on -based nonwoven by the way of dipping drying, then TiO₂/ACF photocatalysis material was prepared via the process of phosphoric acid activation, calcination.. XRD, FTIR, SEM and BET were applied to characterizd TiO₂/ACF photocatalysis material. XRD results show TiO₂ in TiO₂/ACF photocatalysis material is the mixed crystal of anatase and rutile. TiO₂/ACF-1,TiO₂/ACF-2 and ACF has whole quasi graphite micro crystal structure after high temperature carburization and phosphoric acid activation treating; FTIR result illustrates that TiO₂/ACF photocatalysis material has Ti-O bond and Ti-O-C bond of the contact interface of TiO₂ and carbon fibre, which proves the two binding. SEM shows not only TiO₂ collosol but also TiO₂ water dispersions loads on the fibers with TiO₂ existing between fibers, meanwhile, pit and hole can be found on the surface of fibers suggesting fibers has activated to active fibers.TG discussed phosphoric acid as the chemical activator promotes cellulose to dehydrate and form chemical bond with cellulose molecular during the course of calcination. And phosphoric acid promote fiber intermolecular crosslinking and aromatization, making molecular form quasi graphite micro crystal structure.; BET result shows that the specific surface area of TiO₂/ACF-1(500℃) and TiO₂/ACF-2(500℃) is both lower than that of ACF.The photocatalytic property of TiO₂/ACF photocatalysis material was key-point study. TiO₂/ACF-1(500℃) and TiO₂/ACF-2(500℃) both have excellent photocatalysis degradable property, and the solution decoloration rate of methylene blue degradation for 120min is 99.3% and 99.81%; The effect of centrifugal time of TiO₂/ACF photocatalysis material mainly shows that the longer the centrifuge the material is, the better photocatalysis property is, but after centrifugation for 1min and 2min the loading amount decreases, and the photocatalysis property of TiO₂/ACF photocatalysis material is still higher with the decoloration rate more than 90%. For continuous use, methylene blue adsorbs catalytic life without degradation in time and the activity of photocatalysis, so the photocatalysis property of TiO₂/ACF photocatalysis material decreases with the repeat use time increase.