Catalytic reduction of nitrate in water over alumina-supported nickel catalyst toward purification of polluted groundwater
Catalytic reduction of nitrate in water over alumina-supported nickel catalyst toward purification of polluted groundwater
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氧化铝负载的镍催化剂催化还原水中的硝酸盐以净化受污染的地下水
DOI：
10.1016/j.cattod.2020.01.037
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发表时间：
2020
期刊：
影响因子：
5.3
通讯作者：
Kamiya Yuichi
中科院分区：
文献类型：
--
作者：
Kobune Marina;Takizawa Dai;Nojima Jun;Otomo Ryoichi;Kamiya Yuichi
NO3 地下水污染是世界上一个严重的问题。虽然使用包括 Cu-Pd 和 Sn-Pd 在内的 Pd 双金属催化剂催化还原 NO3 是净化地下水的一种有前景的方法，但贵金属的使用是实际应用的主要障碍。在本研究中，我们应用 Ni/Al2O3 催化还原 NO3，并与非负载型 Ni 催化剂进行了催化性能比较。基于催化剂的单位重量，超过5wt.% Ni/Al2O3 的反应速率比无负载Ni催化剂高约5倍。虽然无负载Ni催化剂在低H2分压(=0.75atm)和高浓度NO3–(=800ppm)下完全失活，但即使在还原性较低的条件下([NO3–]0=800ppm和P(H2)=0.5atm)，Ni/Al2O3仍然具有活性。无负载型 Ni 催化剂具有在 310-420°C 下用 H2 还原 NiO 形成的 Ni0 颗粒。另一方面，5wt.% Ni/Al2O3 具有由 NiAl2O4 在 Al2O3 上通过在 450°C 以上用 H2 还原形成的 Ni0 颗粒。这些 Ni0 颗粒可能具有不同的特性，从而具有不同的催化特性。 Ni/Al2O3 的 Ni 负载量对其催化性能有显着影响。对于 5wt.% Ni/Al2O3，NO3-和 H2 的反应级数均为 0.8，而对于 10wt.% Ni/Al2O3，分别为 0 和 –0.2。在10wt.% Ni/Al2O3上，存在两种Ni°颗粒，它们是通过低温（310-420°C）和高温（450°C以上）H2还原形成的。与 Pd-双金属催化剂不同，Ni/Al2O3 上的 NO3– 还原不是通过 NO2– 进行的。
Pollution of groundwater with NO3–is a serious problem in the world. While catalytic reduction of NO3–over Pd-bimetallic catalysts including Cu-Pd and Sn-Pd is a promising method for purification of the groundwater, the use of precious metal is a major obstacle for practical applications. In the present study, we applied Ni/Al2O3for the catalytic reduction of NO3–and compared the catalytic performance with that of unsupported Ni catalyst. The reaction rate over 5 wt.% Ni/Al2O3was about 5 times higher than that of the unsupported Ni catalyst, based on unit weight of catalyst. While the unsupported Ni catalyst was completely deactivated in low partial pressure of H2(=0.75 atm) and high concentration of NO3–(=800 ppm), Ni/Al2O3was still active even under less reductive conditions ([NO3–]0= 800 ppm and P(H2) =0.5 atm). The unsupported Ni catalyst had the Ni0particles formed by the reduction of NiO with H2at 310–420 °C. On the other hand, 5 wt.% Ni/Al2O3possessed the Ni0particles formed from NiAl2O4on Al2O3by the reduction with H2above 450 °C. It is plausible that those Ni0particles had different properties, giving different catalytic properties. The Ni loadings for Ni/Al2O3had a significant impact on the catalytic properties. The reaction orders with respect to both NO3–and H2were 0.8 for 5 wt.% Ni/Al2O3, while those were 0 and –0.2, respectively, for 10 wt.% Ni/Al2O3. On 10 wt.% Ni/Al2O3, there were two kinds of the Ni° particles, which were formed by low (310-420 °C) and high (above 450 °C) temperature H2reductions. Unlike the Pd-bimetallic catalysts, the reduction of NO3–over Ni/Al2O3did not proceed through NO2–.