Catalytic ozonation is a new method used for removal of NH₄OH solution. Therefore, high catalytic performance (activity and selectivity) should be achieved. In this work, we report the synthesis and catalytic performance of Fe₂O₃-Co₃O₄ modified dolomite in the catalytic ozonation of NH₄OH solution. Dolomite was successfully activated and modified with Fe₂O₃ and Co₃O₄. Firstly, dolomite was activated by heating at 800°C for 3 h and followed by KOH treatment. Activated dolomite was modified with Fe₂O₃ by the atomic implantation method using FeCl₃ as Fe source. Fe₂O₃ modified dolomite was further modified with Co₃O₄ by precipitation method. The obtained catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N₂ adsorption–desorption (BET), and temperature-programmed reduction (H₂-TPR). From SEM image, it was revealed that nano-Fe₂O₃ and Co₃O₄ particles with the size of 80–120 nm. Catalytic performance of activated dolomite, Fe₂O₃ modified dolomite, and Fe₂O₃-Co₃O₄ modified dolomite in catalytic ozonation of NH₄⁺ solution was investigated and evaluated. Among 3 tested catalysts, Fe₂O₃-Co₃O₄ modified dolomite has the highest NH₄⁺ conversion (96%) and N₂ selectivity (77.82%). Selectivity toward N₂ over the catalyst was explained on the basis of bond strength M-O in oxides through the standard enthalpy of oxide. Catalyst with lower value has higher N₂ selectivity and the order is the following: Co₃O₄ ( of 60 kcal (mole O)) > Fe₂O₃ ( of 70 kcal (mole O)) > MgO ( of 170 kcal (mole O)). Moreover, high reduction ability of Fe₂O₃-Co₃O₄ modified dolomite could improve the N₂ selectivity by the reduction of NO₃^- to N₂ gas.

中文翻译：

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新型纳米Fe2O3-Co3O4改性白云石及其在氨溶液臭氧化中的高效催化剂的应用

催化臭氧化是一种用于去除NH ₄ OH溶液的新方法。因此，应实现高催化性能（活性和选择性）。在这项工作中，我们报告了Fe ₂ O ₃ -Co ₃ O ₄改性白云石在NH ₄ OH溶液的催化臭氧氧化中的合成和催化性能。用Fe ₂ O ₃和Co ₃ O ₄成功活化和改性了白云石。首先，通过在800°C加热3 h活化白云石，然后进行KOH处理。活化白云石用Fe ₂ O ₃改性通过使用FeCl ₃作为Fe源的原子注入方法。Fe ₂ O ₃改性白云石通过沉淀法进一步用Co ₃ O ₄改性。通过X射线衍射（XRD），傅立叶变换红外光谱（FTIR），能量色散X射线光谱（EDS），扫描电子显微镜（SEM），N ₂吸附-脱附（BET）对所得催化剂进行表征。和程序升温还原（H ₂ -TPR）。从SEM图像可以看出，纳米Fe ₂ O ₃和Co ₃ O ₄粒径为80–120 nm的颗粒。研究和评价了活性白云石，Fe ₂ O ₃改性白云石和Fe ₂ O ₃ -Co ₃ O ₄改性白云石在NH ₄ ⁺溶液的催化臭氧氧化中的催化性能。在3种测试过的催化剂中，Fe ₂ O ₃ -Co ₃ O ₄改性白云石具有最高的NH ₄ ⁺转化率（96％）和N ₂选择性（77.82％）。对N _2的选择性通过氧化物的标准焓通过氧化物的结合强度MO来解释催化剂上的过量。催化剂具有较低值具有高N ₂选择性和顺序如下：钴₃ ø ₄（60千卡（摩尔O））>的Fe ₂ ö ₃（70千卡（摩尔O））>的MgO（170千卡（ O））。此外，铁的高还原能力₂ ö ₃ -Co ₃ ö ₄改性白云石可改善的N个₂由NO的还原选择性₃ ^-到N _2种气体。