可见光辐射下活性炭-铁酸镍杂化催化剂光催化氧化氨氮(英文)

Photocatalytic Oxidation of Ammonia via an Activated Carbon-Nickel Ferrite Hybrid Catalyst under Visible Light Irradiation

铁酸镍(NiFe2O4)中的镍原子抑制其光芬顿催化活性.然而,活性炭(AC)能激活其光芬顿催化活性,结果导致复合催化剂AC-NiFe2O4在过氧化氢存在时可见光辐射下也可催化氧化氨氮.用X射线衍射(XRD),透射电镜(TEM),傅里叶变换红外(FTIR)光谱,紫外-可见漫反射光谱(UV-Vis DRS),比表面积和振动样品磁强计对催化剂进行了表征.光催化降解氨氮的实验表明,该复合催化剂在10 h内氨氮的降解率可达到91.0%,而同样条件下没有催化剂时氨氮的去除率只有24.0%.对照实验表明,裸铁酸镍在可见光辐射下,氨氮的降解率只有30.0%.这表明活性炭加速了氨氮的氧化速率.动力学研究表明,氨氮的氧化遵循一级反应动力学规律,其表观反应动力学常数为3.538×10-3min-1.机理研究表明,氨氮的氧化是通过生成HONH2中间体,然后转化为NO2-.8次循环实验表明该复合催化剂容易分离、可循环使用、且催化活性十分稳定.因此,该催化剂具有潜在的应用价值.

The nickel atoms in a metal ferrite lattice inhibit photocatalytic activity with hydrogen peroxide, However, activated carbon bonded on nickel ferrite （AC-NiFe204） induces photocatalytic activity of nickel ferrite with hydrogen peroxide, enabling photo-Fenton catalytic oxidation of ammonia under visible-light irradiation in the presence of hydrogen peroxide. The AC-NiFe20, catalyst was characterized using X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and a vibrating sample magnetometer at room temperature. The photocatalytic tests showed that the ammonia degradation efficiency approached 91.0% in the presence of the AC-NiFe204 catalyst, whereas the efficiency was only 24.0% without the catalyst under similar conditions over 10 h. Another test showed that the single NiFe20, catalyst achieved a degradation efficiency of only 30.0% under similar conditions, indicating that activated carbon can accelerate the rate of ammonia oxidation. Exploration of the oxidation mechanism showed that the oxidation pathway involves an HONH2 intermediate, forming nitrite ions. Kinetic studies showed that the oxidation of ammonia follows a pseudo-first order kinetic law, with a rate constant of 3.538×10^-3 min^-1. The catalyst was used in eight runs, and shown to be stable, recoverable, separable, and reusable, suggesting that it has potential applications in the disposal of ammonia.