Aqueous bromate reduction by catalytic hydrogenation over Pd/Al2O3 catalysts
Aqueous bromate reduction by catalytic hydrogenation over Pd/Al2O3 catalysts
复制标题
Pd/Al2O3 催化剂催化加氢还原溴酸盐水溶液
DOI：
10.1016/j.apcatb.2010.02.021
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发表时间：
2010-06-07
影响因子：
22.1
通讯作者：
Zheng, Shourong
中科院分区：
文献类型：
--
作者：
Chen, Huan;Xu, Zhaoyi;Zheng, Shourong
溴酸盐是饮用水中公认的氧卤化物消毒副产物。本研究制备了不同SiO2、Al2O3和活性炭（AC）载体的贵金属（Pd、Pt）催化剂，并对溴酸盐水溶液的催化加氢进行了初步研究。表征结果表明，Pd/SiO2和Pd/Al2O3催化剂的等电点（IEP）分别在2.0和8.0左右，而Pd/AC催化剂的等电点远低于2.0。与Pd/SiO2和Pd/AC相比，在pH 5.6时，由于溴酸盐离子与Pd/Al2O3之间的静电吸引相互作用，Pd/Al2O3对溴酸盐的还原表现出更高的催化活性。此外，初始浓度为0.39 mM的溴酸盐在Pt/Al2O3上的去除率为80.2%，在Pd/Al2O3上的去除率接近100%，表明Pd/Al2O3具有较高的催化活性。对于Pd/Al2O3，溴酸盐的还原遵循Langmuir-Hinshelwood模型，反映了吸附控制的还原机制。增加Pd的负荷量可以增强溴酸盐的还原。此外，溴酸盐的还原具有强烈的ph依赖性，在低ph下还原速率可以提高。当阴离子（Cl-、Br-和SO42-）共存时，溴酸盐的还原受到抑制，其中SO42-表现出最显著的抑制作用，这归因于对活性表面位点的竞争性吸附。研究结果表明，催化加氢法是一种很有潜力的去除饮用水中溴酸盐的处理技术。(C) 2010 Elsevier B.V.版权所有
Bromate is recognized as an oxyhalide disinfection byproduct in drinking water. In this study, supported noble metal (Pd, Pt) catalysts with different supports of SiO2, Al2O3 and activated carbon (AC) were prepared and the catalytic hydrogenation of aqueous bromate was first investigated. Characterization results showed the isoelectric points (IEPs) of Pd/SiO2 and Pd/Al2O3 catalysts were around 2.0 and 8.0, respectively, whereas the IEP of Pd/AC was much lower than 2.0. In comparison with Pd/SiO2 and Pd/AC, Pd/Al2O3 exhibited a substantially higher catalytic activity at pH 5.6 for bromate reduction due to the electrostatic attractive interaction between the bromate ion and the catalyst. Moreover, bromate with an initial concentration of 0.39 mM was removed by 80.2% over Pt/Al2O3 and nearly 100% over Pd/Al2O3 after reaction for 2 h, indicative of a higher catalytic activity of Pd/Al2O3. For Pd/Al2O3, the bromate reduction followed the Langmuir-Hinshelwood model, reflecting an adsorption controlled reduction mechanism. Increasing Pd loading amount resulted in enhanced bromate reduction. In addition, the bromate reduction was found to be strongly pH-dependent and enhanced reduction rate could be achieved at low pH. In the presence of coexisting anions (Cl-, Br- and SO42-) the bromate reduction was suppressed, wherein SO42- exhibited the most marked inhibition effect, attributed to competitive adsorption for active surface sites. The present results indicate that catalytic hydrogenation can be used as a potential treatment technique for the removal of bromate in drinking water. (C) 2010 Elsevier B.V. All rights reserved.