Accelerated generation of free radicals by iron oxide nanoparticles in the presence of an alternating magnetic field.
Accelerated generation of free radicals by iron oxide nanoparticles in the presence of an alternating magnetic field.
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作者：
Wydra RJ;Oliver CE;Anderson KW;Dziubla TD;Hilt JZ
氧化铁纳米颗粒的表面能够通过芬顿和哈伯-韦斯反应催化产生活性氧（ROS）。芬顿化学已被证明是温度依赖性的，其活性在高达40 °C时增加，然后在高于该温度时降低，因为过氧化氢降解成氧气和水，这限制了反应。当暴露于交变磁场（AMF）时，氧化铁纳米颗粒从磁场中吸收能量并将其转化为热量。在这项研究中，当磁铁矿纳米颗粒（Fe 3 O 4）的悬浮液暴露于AMF时，我们观察到亚甲基蓝的降解增加，这表明响应AMF的活性氧产生增加。与Arrhenius预测相比，ROS生成的增加是时间和浓度依赖性的;其中我们观察到ROS增强随着暴露时间和浓度的增加而减少。我们假设，减少是由于在场的团聚。随着纳米颗粒附聚，单位质量的表面积减少，限制了反应速率。
The surfaces of iron oxide nanoparticles are capable of catalytically generating reactive oxygen species (ROS) through the Fenton and Haber-Weiss reactions. Fenton chemistry has been shown to be temperature dependent with an increase in activity up to 40 °C and then a decrease above this temperature as the hydrogen peroxide degrades into oxygen and water which limits the reaction. When exposed to an alternating magnetic field (AMF), iron oxide nanoparticles absorb the energy from the magnetic field and convert it into heat. In this study, we observed an increase in the degradation of methylene blue when a suspension of magnetite nanoparticles (Fe3O4) was exposed to an AMF indicating there was an increase in the ROS generation in response to the AMF. The increase in ROS generation compared to the Arrhenius prediction was both time and concentration dependent; in which we observed a decrease in ROS enhancement with increased time of exposure and concentration. We postulate that the decrease is due to agglomeration in the presence of the field. As the nanoparticles agglomerate, there is a decrease in surface area per mass limiting the reaction rate.