氟离子对TiO2/膨润土光催化降解酸性桃红的影响

研究了在紫外光照射下, 添加氟离子对P25(锐钛矿)和TiO2/膨润土光催化降解酸性桃红(SRB)的影响. 紫外可见光谱测定结果表明无氟的反应体系, pH值越小, 光降解速率越快; pH值固定, 添加氟离子越多, 反应速率越快, 在TiO2/膨润土催化剂上, 当氟离子浓度达到一定程度时, 反应速率不再变化. 在P25和TiO2/膨润土催化剂上, 添加氟离子对H2O2的产生量影响不同, 通过电子顺磁共振(EPR)技术探测到了超氧自由基和羟基自由基, 这两个体系添加氟离子对其产生强度影响不同, 这可能是因为TiO2/膨润土催化剂为层状结构, BET 比表面积较大, 经XRD和TEM测试表明其晶粒直径约为57.9 nm. TiO2/膨润土催化剂连续循环使用11次, 光催化活性基本不变, 这个现象说明TiO2/膨润土催化剂既易于从分散体系中分离出来, 而且其稳定性也好, 它是一个有应用前途的催化剂.

Effect of Fluoride Ion on the Photocatalytic Degradation of Sulforhodamine B on TiO2/Bentonite

The effect of fluoride ion on the photocatalytic degradation of sulforhodamine B (SRB) on P25 and TiO2/bentonite under UV light irradiation was studied. The results of UV-Vis spectra detection showed that lower pH value lead to higher photodegradation rate in the absense of fluoride ion. And if pH value is fixed, the more the fluoride ion concentration, the faster the reaction rate will be. On TiO2/bentonite catalyst, when fluoride ion concentration reaches a definite value, its reaction rate will not change. The effect of fluoride ion on the production of H2O2 on P25 is different from that on TiO2/bentonite. Superoxide radical and hydroxyl radical were detected by electron paramagnetic resonance (EPR) technique. The effects of fluoride ion on these two systems are different. These phenomena may be caused by the special structures of TiO2/bentonite, which is a pillared structure with a large BET surface area and a particle size of about 57.9 nm by XRD and TEM. TiO2/bentonite catalyst was used for 11 cycles continuously, and its photocatalytic reactivity was stable. This phenomenon shows that TiO2/bentonite catalysts are easier to be separated from a dispersion system and their stability is good. It is a promising catalyst.