Investigation in mechanistic issues of sonocatalysis and sonophotocatalysis using pure and doped photocatalysts
Investigation in mechanistic issues of sonocatalysis and sonophotocatalysis using pure and doped photocatalysts
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DOI：
10.1016/j.ultsonch.2014.06.008
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发表时间：
2015-01-01
影响因子：
8.4
通讯作者：
Moholkar, Vijayanand S.
中科院分区：
文献类型：
--
作者：
Chakma, Sankar;Moholkar, Vijayanand S.
本文研究了声催化和声光催化两种高级氧化工艺的机理问题，其中声催化和声光催化是两种单独的高级氧化工艺的结合。采用了三种光催化剂，即纯ZnO和Fe掺杂ZnO（两种方案）。Fe掺杂的ZnO催化剂已经使用标准技术表征。以两种纺织染料的脱色为模型反应。通过改变介质中超声和空化现象的特性的实验，已经使用定量码尺确定了两种AOP之间的确切协同作用。结果表明，两种AOP之间的负协同作用，这是一个几乎一致的结果，使用所有三种光催化剂的两种染料的脱色。Fe掺杂的ZnO催化剂有助于产生更多的（OH）-O-中心点自由基，可以增强脱色。然而，这些自由基主要与吸附在催化剂表面的染料分子反应。空化气泡产生的强烈冲击波导致染料分子从催化剂表面脱附并降低染料-自由基相互作用的可能性，从而降低光化学产生的（OH）-O-中心点自由基对染料脱色的净效用。这是声分解和声分解之间的负协同作用的基本原理。Fe掺杂的ZnO催化剂提高了脱色的程度，但两个单独的AOP之间的协同作用仍然没有改变掺杂。(C)2014爱思唯尔有限公司版权所有。
This paper attempts to investigate the mechanistic issues of two hybrid advanced oxidation processes (HAOPs), viz. sonocatalysis and sonophotocatalysis, in which the two individual AOPs, viz. sonolysis and photocatalysis, are combined. Three photocatalysts, viz. pure ZnO and Fe-doped ZnO (with two protocols) have been employed. Fe-doped ZnO catalyst has been characterized using standard techniques. Decolorization of two textile dyes has been used as the model reaction. With experiments that alter the characteristics of ultrasound and cavitation phenomena in the medium, the exact synergy between the two AOPs has been determined using a quantitative yard stick. The results revealed a negative synergy between the two AOPs, which is an almost consistent result for decolorization of both dyes using all three photocatalysts. Fe-doping of ZnO catalyst helps in generation of more (OH)-O-center dot radicals that could augment decolorization. However, these radical mainly react with dye molecules adsorbed on catalyst surface. Intense shock waves generated by cavitation bubbles cause desorption of dye molecules from catalyst surface and reduce the probability of dye-radical interaction, thus reducing the net utility of photochemically generated (OH)-O-center dot radicals towards dye decolorization. This is rationale underlying the negative synergy between sonolysis and photocatalysis. Fe-doped ZnO catalyst increases the extent of decolorization, but the synergy between the two individual AOPs remains unaltered with doping. (C) 2014 Elsevier B.V. All rights reserved.