Dynamic change of copper in fly ash during de novo synthesis of dioxins.
Dynamic change of copper in fly ash during de novo synthesis of dioxins.
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DOI：
10.1021/es048019f
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发表时间：
2005-07
影响因子：
11.4
通讯作者：
M. Takaoka;A. Shiono;K. Nishimura;Takashi Yamamoto;T. Uruga;N. Takeda;Tsunehiro Tanaka;K. Oshita-K.-Osh
中科院分区：
文献类型：
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作者：
M. Takaoka;A. Shiono;K. Nishimura;Takashi Yamamoto;T. Uruga;N. Takeda;Tsunehiro Tanaka;K. Oshita-K.-Osh
尽管许多研究人员已经报道，在涉及模型粉煤灰的热实验中，氯化铜是产生相对大量二恶英的重要催化剂，但铜在此过程中的行为细节仍然无法获得。在本研究中，我们采用原位XANES实验，涉及一种来自城市固体废物焚烧炉（MSWI）的真实粉煤灰和两种粉煤灰模型，研究了铜在适合重新合成的温度下的行为，这是垃圾焚烧和热过程中二恶英的主要形成途径。实际飞灰和模拟飞灰A中的铜化合物(CuCl2.2H2O +活性炭（AC) +氮化硼（BN））在低温下还原为亚铜化合物或单质铜。实际粉煤灰的Cu XANES光谱变化与模型粉煤灰A和氧化氯化催化剂的相似。在模型粉煤灰B （CuO + AC + KCl + BN）中，CuO在研究温度范围内变化不大。在这项研究中，我们发现了强有力的证据，证明氧化氯化作用是二恶英形成的关键机制步骤，在真实的城市生活垃圾和模型粉煤灰中都发生了。
Although many researchers have reported that copper chloride is an important catalyst that generates relatively large amounts of dioxins in heat experiments involving model fly ash, details on the behavior of copper during the process are still unavailable. In this study, we used in situ XANES experiments involving one type of real fly ash, which originated from a municipal solid-waste incinerator (MSWI), and two fly ash models to investigate the behavior of copper in fly ash at temperatures that are suitable for de novo synthesis, which is the major formation route for dioxins during waste incineration and thermal processes. Cupric compounds in real fly ash and model fly ash A(CuCl2.2H2O + activated carbon (AC) + boron nitride (BN)) were reduced to cuprous compounds or elemental copper at low temperatures. The changes in the Cu XANES spectra of real fly ash were similar to those of model fly ash A and those of an oxychlorination catalyst. In model fly ash B (CuO + AC + KCl + BN), CuO did not vary dramatically in the temperature range studied. In this study, we found strong evidence that oxychlorination, the key mechanistic step in the formation of dioxins, occurred in both real MSWI and model fly ash.