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A New Method for Removal of Hydrogen Peroxide Interference in the Analysis of Chemical Oxygen Demand

机译：消除化学需氧量分析中过氧化氢干扰的新方法

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摘要

Many advanced oxidation processes involve addition of hydrogen peroxide (H_2O_2) with the aim of generating hydroxyl radicals to oxidize organic contaminants in water. However, chemical oxygen demand, a common measure of gross residual organic contamination, is subject to interference from residual H_2O_2 in the treated water. A new method, involving catalytic decomposition of H_2O_2 with addition of heat and sodium carbonate (Na_2CO_3), is proposed in this work to address this problem. The method is demonstrated experimentally, and modeled kinetically. Results for 5 mM H_2O_2 in deionized (DI) water included reduction to below the COD detection limit after 60 min heating (90℃) with addition of 20 g/L Na_2CO_3 concentrated solution, whereas 900 min were required in treated municipal wastewater. An approximate second order rate constant of 11.331 M~(-1)·min~(-1) at Na_2CO_3 dosage of 20 g/L was found for the tested wastewater. However, kinetic modeling indicated a two-step reaction mechanism, with formation of peroxocarbonate (CO_4~(2-)) and ultimate decomposition to H_2O and O_2 in pure H_2O_2 solution. A similar mechanism is apparent in wastewater at high catalyst concentrations, whereas at low Na_2CO_3 addition rates, the catalytic effects of other constituents appear important.
机译：许多先进的氧化过程都涉及添加过氧化氢（H_2O_2），目的是生成羟基自由基以氧化水中的有机污染物。但是，化学需氧量是总残留有机污染物的一种常用量度，它受到处理后水中残留H_2O_2的干扰。为了解决这个问题，本工作提出了一种新的方法，该方法涉及通过添加热量和碳酸钠（Na_2CO_3）催化分解H_2O_2。该方法通过实验证明，并进行动力学建模。去离子（DI）水中5 mM H_2O_2的结果包括在加热60分钟（90℃）后添加20 g / L Na_2CO_3浓溶液降至COD检测极限以下，而处理后的城市废水则需要900 min。发现Na_2CO_3剂量为20 g / L时，近似二级速率常数为11.331 M〜（-1）·min〜（-1）。然而，动力学模型表明反应机理是两步的，形成过氧碳酸盐（CO_4〜（2-））并在纯H_2O_2溶液中最终分解为H_2O和O_2。在高催化剂浓度的废水中，类似的机理很明显，而在低Na_2CO_3添加速率下，其他成分的催化作用显得很重要。

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  • 来源
    《Environmental Science & Technology》 |2012年第4期|p.2291-2298|共8页
  • 作者

    Tingting Wu; James D. Englehardt;

  • 作者单位

    Department of Civil, Architectural and Environmental Engineering, University of Miami, 1251 Memorial Drive, MEB 314, Coral Gables, Florida 33146, United States;

    Department of Civil, Architectural and Environmental Engineering, University of Miami, P.O. BOX 248294, Coral Gables, Florida 33124-0630, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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