| Appearance and accumulation of pharmaceutical and personal care products(PPCPs) in the water environment cause a potential threat to the ecosystem and human beings, and have become the focus of global environmental problems. Titanium dioxide photocatalytic technology,which has many outstanding advantages such as mild reaction conditions, low energy consumption and making the most organic pollutants mineralized, is more effective in dealing with the refractory organic matter than other traditional water treatment technologies.In this paper, hydrothermal method is used to optimize the preparation of the titanium dioxide film with exposed {001} facets. On the basis of the early stage of the research study, this paper mainly discussed influence of two factors: adding different of alcohols and the concentration of hydrofluoric acid on the morphology of titanium dioxide film with exposed {001} facets. When we added isopropanol and hydrofluoric acid concentration was 0.03mol/L, we found that the synthesized titanium dioxide film is more stable and the exposed {001} facets are more completed.Low-temperature electrostatic self-assembly method was used to deposit noble metals on titanium dioxide surface, and the effects of the variety of factors such as kinds of noble metal, sol p H, sol temperature, immersion time on the morphology and dispersion of noble metals and photocatalytic degradation of bezafibrate which is typical PPCPs in aqueous solution were evaluated. The results show that Platinum(Pt) deposited titanium dioxide film with exposed {001} facets has more excellent photocatalytic activity. When the p H value of Pt sol is equal to 4 and the temperature of Pt sol is equal to 0, the balance of electrostatic adsorption force between the titanium dioxide film and the Pt particles and electrostatic repulsion between Pt particles(reducing the inter-particles aggregation and increasing the particles dispersion) can achieve the optimal. Both quantity and particle size of ultrafine Pt nanoparticles increase with the extension of immersion time. Titanium dioxide film with exposed {001} facets was dipping in Pt sol in 5 min, as prepared Pt deposited titanium dioxide film with exposed {001} facets has the highest photocatalytic activity to degrade bezafibrate, and 10 mg/L bezafibrate can be degraded below detection limit in 12 min under VUV irradiation The first order reaction rate constant of bezafibrate degradation by Pt deposited titanium dioxide film with exposed {001} facets is 2.03 times of that without Pt deposited titanium dioxide film with exposed {001} facets.The effect of initial concentration on bezafibrate degradation of photocatalytic activity, repeatability and stability by Pt deposited titanium dioxide film with exposed {001} facets was evaluated. Results show that when the initial concentration of bezafibrate are 5 mg/L and 1 mg/L, Pt deposited titanium dioxide film with exposed {001} facets has higher activity than titanium dioxide film with exposed {001} facets, the total organic carbon(TOC) removal efficency is reached 70% in 24 min, and the catalyst shows good repeatability and stability.XRD, SEM, TEM, Raman and XPS were also used to character the Pt deposited titanium dioxide film with exposed {001} facets. By XPS analysis, we found that after calcination process, deposited zero price of Pt particles are partially oxidized into bivalent oxidizing species: Pt Oabs. And after the photocatalytic reaction, the proportion of Pt Oabs oxidizing species has a little increasing. Existing of Pt particles with some bivalent Pt oxidizing species can act as electron capture center and strengthen the life of photo-generated electrons and holes, thereby improve the photocatalytic activity. |
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