FeO is one of the main compositions of sludge-incinerated fly ash and shows reactivity for chromium removal from flue gas in the incinerator. Experiments and density functional theory (DFT) calculations were performed to investigate the high-temperature reaction chemistry of chromium and chlorine over FeO within fly ash. FeO exhibits outstanding chromium removal efficiency of 86.29 % in N atmosphere. The presence of HCl obviously inhibits chromium removal, the inhibition effect increases with increasing HCl concentration. Fe-Cr composite oxides are the main products of chromium-FeO high-temperature reaction. Chromium within the reaction products in N or HCl-containing atmosphere mainly exists in the form of Cr. O addition leads to the formation of a small amount of Cr. FeO exhibits excellent inhibition performance of chromium oxidation. DFT calculations suggest that CrCl and CrOCl are chemically adsorbed on FeO surface. Both O and Fe atoms of FeO surface serve as active sites for chromium adsorption. HCl is dissociatively adsorbed on the FeO surface, and reacted with chromium to form CrCl. CrCl formation on the FeO surface is dominated by a four-step reaction pathway: Cr(ads) → CrCl(ads) → CrCl(ads) → CrCl(ads) → CrCl. CrCl formation is the rate-determining step with the energy barrier of 39.51 kJ/mol.

中文翻译：

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污泥焚烧飞灰中铬和氯在 Fe2O3 上的高温反应化学

FeO 是污泥焚烧飞灰的主要成分之一，对焚烧炉烟气中的铬具有去除活性。通过实验和密度泛函理论 (DFT) 计算来研究飞灰中铬和氯在 FeO 上的高温反应化学。 Fe3O 在 N 气氛中表现出出色的铬去除效率，可达 86.29%。 HCl的存在明显抑制铬的去除，且抑制效果随着HCl浓度的增加而增强。 Fe-Cr复合氧化物是铬-FeO高温反应的主要产物。在含N或HCl气氛中反应产物中的铬主要以Cr的形式存在。 O的添加导致形成少量的Cr。 Fe3O表现出优异的铬氧化抑制性能。 DFT 计算表明 CrCl 和 CrOCl 以化学方式吸附在 FeO 表面上。 FeO表面的O和Fe原子都是铬吸附的活性位点。 HCl解离吸附在FeO表面，并与铬反应生成CrCl。 FeO表面上CrCl的形成主要通过四步反应途径：Cr(ads)→CrCl(ads)→CrCl(ads)→CrCl(ads)→CrCl。 CrCl 的形成是速率决定步骤，其能垒为 39.51 kJ/mol。