低温等离子体耦合Fe2O3催化剂去除粮食仓储环境中磷化氢

为了探究低温等离子体（Non-Thermal Plasma，NTP）耦合催化剂对粮仓中磷化氢（PH3）的去除效果，该文采用介质阻挡放电低温等离子体与催化剂耦合的反应装置，研究了NTP与Fe2O3催化剂耦合对PH3去除率的影响，并对耦合反应后的催化剂进行表征，分析产物及反应机理。结果表明，载体和催化剂与NTP耦合改变了NTP的放电状态，提高了PH3去除率；不同载体负载Fe2O3后，在输入功率超过53 W时，NTP与Fe2O3催化剂耦合对PH3去除率均高于无填充，Fe2O3/Al2O3与NTP耦合效果最好，去除效率达到了100%。耦合前后催化剂的表征结果表明，耦合反应之后，Fe2O3/Al2O3催化剂的比表面积降低了11.23%，Fe3+/(Fe2++Fe3+)含量提高了21.06%，Osur/(Olatt+Osur+Oads)含量减少了2.24%，Fe含量降低了4.69%，P含量增加了4.34倍。产物分析表明耦合后生成的主要产物为磷酸。研究结果表明NTP耦合Fe2O3/Al2O3催化剂具有很好的PH3去除效果，为粮食仓储行业去除磷化氢提供理论依据。

Removal of phosphine from grain storage environment via non-thermal plasma combined with Fe2O3 catalyst

Abstract: Phosphine (PH3) has been the most popular fumigant in use for pest control during the disinfestation of dry plant products. Since the PH3 is a colorless, flammable, and very toxic gas with a fishy or garlic smell, it is necessary to monitor the PH3 emission in a granary after fumigation. The Non-Thermal Plasma (NTP) combined with some catalysts has been widely expected to serve as a promising technique to detect Volatile Organic Gases (VOCs). However, there is little research about the NTP coupled iron oxide catalyst to remove the PH3 contaminant. In this study, a systematic investigation was made to clarify the effects of NTP combined with Fe2O3 catalysts on the PH3 removal efficiency using a dielectric barrier discharge NTP combined with a catalyst reaction device. The microstructure of catalysts after the coupling reaction was characterized by the Brunauer-Emmett-Teller (BET), X-ray powder Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The products and reaction mechanism were analyzed after removing PH3. The results showed that the NTP combined with the carriers and catalysts changed the discharge state for the higher removal efficiency of PH3. Once the input power exceeded 53 W, the removal efficiencies of PH3 by the NTP combined with Fe2O3 catalysts were much higher than that with the plasma alone. Furthermore, the Fe2O3/Al2O3 catalysts presented the best coupling effect during the removal of PH3 contaminant. Once the input power was 58 W, the removal efficiencies of plasma alone, Al2O3, and Fe2O3/Al2O3 were 29%, 31.29%, 100%, respectively. More importantly, the specific surface area of Fe2O3/Al2O3 catalyst decreased by 11.23% after the coupling reaction, the content of Fe3+/(Fe2++Fe3+) increased by 21.06%, the content of Osur/(Olatt+Osur+Oads) decreased by 2.24%, the content of Fe decreased by 4.69%, and the content of P increased by 4.34 times. Moreover, phosphoric acid was the main product during the treatment. The high-energy electrons and active substances produced by NTP were directly reacted with PH3, and also acted on the Fe2O3 catalyst, leading to the change of discharge state. Further, the REDOX reaction of Fe3+ was participated to produce more surface reactive oxygen species, so that the PH3 adsorbed on the surface of the catalysts was oxidized into the phosphoric acid, indicating a higher removal efficiency of PH3. Consequently, the NTP combined with Fe2O3/Al2O3 catalyst better performed the PH3 removal efficiency. The finding can provide a strong theoretical basis to remove the phosphine contaminant from the grain storage industry.