Sonocatalytic facilitation of hydroxyl radical generation in the presence of TiO2
Sonocatalytic facilitation of hydroxyl radical generation in the presence of TiO2
复制标题
DOI：
10.1016/j.ultsonch.2008.04.011
复制
发表时间：
2008-09-01
影响因子：
8.4
通讯作者：
Sakiyama, Kazumichi
中科院分区：
文献类型：
--
作者：
Shimizu, Nobuaki;Ogino, Chiaki;Sakiyama, Kazumichi
研究了超声波辐照和tio2存在下羟基自由基（CH）的生成。通过对水杨酸氧化反应的考察，评价了tio2对超声系统氧化能力的影响。在不同的实验条件下，采用高效液相色谱联用电化学检测方法测定水杨酸衍生物2,3-二羟基苯甲酸（DHBA）和2,5-DHBA的生成。在超声辐照过程中，tio2(2)的存在增强了DHBA的生成，表明超声系统具有较高的氧化能力。辐照过程中，Al(2)O(3)也增加了DHBA的生成；然而，TiO(2)的效果高于Al(2)O(3)。OH自由基清除剂如二甲基亚砜（DMSO）、甲醇和甘露醇的加入可显著抑制DHBA的产生，其中DMSO的抑制作用在所有清除剂中最高。进一步研究了溶解气体对OH自由基生成的影响，发现OH自由基的功率为Xe > At >o (2) >n(2)。辐照溶液的脱气完全抑制了CH自由基的生成。这些结果表明，tio2的存在加速了超声辐照过程中OH自由基的生成，这一过程可能是通过在辐照溶液中诱导空化气泡来介导的。(c) 2008 Elsevier B.V.版权所有
The generation of hydroxyl (CH) radicals was investigated during ultrasonic irradiation and in the presence of TiO(2). The effect of TiO(2) on an ultrasonic system's oxidation power was evaluated by examining the oxidation of salicylic acid. The generation of the salicylic acid derivatives, 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA, was measured by high-performance liquid chromatography coupled with electro-chemical detection under different experimental conditions. The presence of TiO(2) enhanced the generation of DHBA during ultrasonic irradiation, thus indicating a higher oxidation power in the ultrasonic system. Al(2)O(3) also increased the generation of DHBA during irradiation; however, the effect of TiO(2) was found to be higher than that of Al(2)O(3). The addition of OH radical scavengers such as dimethylsulfoxide (DMSO), methanol and mannitol significantly suppressed the production of DHBA, and DMSO was found to have the highest suppressive effect among all scavengers. The effects of dissolved gases on the generation of OH radicals were further studied, and their power was found to be in the order Xe > At > O(2) > N(2). The degassing of the irradiation solution completely suppressed the generation of CH radicals. These results indicate that the presence of TiO(2) accelerates the generation of OH radicals during ultrasonic irradiation, and that the process may be mediated through the induction of cavitation bubbles in irradiating solutions. (c) 2008 Elsevier B.V. All rights reserved.