TiO2体系对酸性红B的催化超声降解过程的影响

采用处理过的市售的锐钛型和金红石型纳米TiO2作为声催化剂,低功率的超声波作为激发源,研究了纳米TiO2对酸性红B催化超声降解过程的影响.结果表明:锐钛矿纳米TiO2和金红石型纳米TiO2对酸性红B有着不同的超声降解过程.锐钛型纳米TiO2以空穴氧化为主,使酸性红B脱色和降解过程同时进行,而金红石型纳米TiO2则以自由基氧化为主,是先脱色后降解.锐钛型纳米TiO2降解效果明显优于金红石型纳米TiO2.单纯超声照射下酸性红B没有明显的脱色和降解过程发生.因此,锐钛型纳米TiO2催化超声降解有机污染物的方法具有很好的应用前景.

EFFECT OF TiO2 POWDER ON SONOCATALYTIC DEGRADATION PROCESS OF ACID RED B

By using treated anatase and rutile nanometer TiO2 powders as the sonocatalysts and low power ultrasound as an irradiation source to induce TiO2 particles, the sonocatalytic degradation of acid red B in the presence of nanometer TiO2 powder was studied. it was found that there are different decomposition processes of the acid red B in aqueous solution, with anatase or rutile nanometer TiO2 powders. For anatase nanometer TiO2 catalyst, the acid red B is mainly oxidated by the cavities on the surface of the TiO2 particles, so that the decolorization and degradation occur at the same time. For the rutile nanometer T~O2 catalyst, the acid red B was mainly oxidated by the .OH radicals, so that decolorization of the TiO2 particles occurs first, and then the degradation of naphthyl ring follows. However, the experimental results also indicate that the degradation effect of acid red B in the presence of anatase nanometer TiO2 powder is obviously better than that in the presence of rutile nanometer TiO2 powder, while there is no obvious decolorization and degradation in the absence of any TiO2 catalyst and only with ultrasonic irradiation. Hence, sonocatalytic degradation in the presence of anatase nanometer TiO2 catalyst is an advisable choice for the treatment of organic wastewater in the future.