Preparation And Photo-catalytic Activity Of Tio₂ Doped With Iron And Nitrogen Coating On Forming Fly Ash Absorbent

In the paper, tetranbutyl titanate was loaded on self-made fly ash based adsorbent using sol–gel dip-coating technique to form N,Fe-TiO2/FFA photocatalyst, which was characterized by UV-Vis spectrum, FTIR, SEM and XRD to investigate the structure and properties of the samples. Moreover, considering methylene blue (MB) as target degradation dye, calcination time, catalyst dose, heat treatment temperature was also examined. The result indicated that the photocatalyst doped with N, Fe ion showed more excellent catalytic ability under visible light irradiation. The photodegradation rate reached 92.6% at 500℃when the pH value in sol, calcination time and dose were 6, 2h, 5g/L, rerespectively. In addition, when pH in MB solution was adjusted to be alkaline, there was a greater increase in degradation property, being up to 97% or more.Degradation effect of reactive brilliant blue on pholocatalyst was explored. The optimal light intensity was 90W; the optimal pH value was 4. When the dose of H2O2 was 4ml, photo degradation efficiency of reactive brilliant blue was the fastest. The results exhibited that photocatalytic degradation coincided with first-order photocatalysis reaction equation and surface reaction rate constant k increased with the increase of concentration.Photocatalytic reactor was made to simulate formaldehyde pollution. The purification efficiency of photocatalytic degradation of formaldehyde gas on several parameters, such as calcination temperature, light intensity, humidity , initial concentration, were investigated by means of using N,Fe-TiO2/FFA photocatalyst. In the meantime, reaction kinetics of photocatalytic degradation of formaldehyde gas was discussed as well. The results demonstrated that the optimal catalyst dose and system humidity were 50g/0.32m3, 40%. Besides, the degradation efficiency was 67% at 180min when the formaldehyde concentration was 7.1 mg/m3. Furthermore, photocatalytic reaction of formaldehyde was in line with L-H kinetic model and degradation reaction agreed with first-order kinetics. With the initial concentration of formaldehyde increased, the photocatalytic reaction rate constant k increased gradually and Langmuir adsorption constant K decreased along with the increase of initial concentration of formaldehyde.