{"title":"高性能氧化镁吸附剂对硝酸盐和亚硝酸盐阴离子协同促进机制的新解释","authors":"Shuo Zhao, Panpan Wang, Hongxia Guo, Xiao Wang, Huan Wang, Wenquan Cui","doi":"10.1016/j.seppur.2024.129971","DOIUrl":null,"url":null,"abstract":"The mechanism of CO<sub>2</sub> capture on the nitrate and nitrite anion species synergistic promoted MgO has been rarely studied and still not fully understood. Herein we report a systematic investigation on the CO<sub>2</sub> adsorption performance of molten salts-promoted MgO adsorbent to deeply reveal the synergistic promoted mechanism of nitrate and nitrite. A series of MgO-based solid adsorbents were synthesized and applied for CO<sub>2</sub> capture using NaNO<sub>2</sub>/KNO<sub>3</sub> as promoters. The addition of mixed nitrate and nitrite promoters greatly enhances the adsorption capacity of MgO, exhibiting CO<sub>2</sub> capture up to 10.25 mmol·g<sup>−1</sup> under optimal conditions. The MgO-based adsorbent in the form of nanosheets has faster adsorption kinetics and better stability, and the possible reaction mechanism of MgO modified by nitrate and nitrite was proposed. Firstly, NO<sub>3</sub><sup>–</sup> interacts with the lattice oxygen (O<sub>1</sub><sup>2-</sup>) of MgO to form NO<sub>2</sub><sup>–</sup> and O<sub>2</sub><sup>2–</sup>. Secondly, Mg<sup>2+</sup> interacts with the free NO<sub>2</sub><sup>–</sup> to form [Mg···NO<sub>2</sub>]<sup>+</sup> and further overcomes the energy barrier to generate [Mg<sup>2+</sup>···O<sup>2–</sup>] ion pairs. O<sub>2</sub><sup>2–</sup> is not stable and prone to side reaction. However, NO<sub>2</sub><sup>–</sup> can be converted into O<sub>2</sub><sup>–</sup>, and O<sub>2</sub><sup>–</sup> is further generated to O<sub>2</sub><sup>2–</sup>, facilitating regeneration of NO<sub>3</sub><sup>–</sup>. The introduction of molten salt can significantly reduce the reaction energy barrier, and the energy barrier required to generate [Mg<sup>2+</sup>···O<sup>2–</sup>] ion pairs is reduced from 6.86 eV to 3.50 eV. Adsorption kinetics studies reveal that the nano-flake MgO facilitates the full contact with the promoter and has faster reaction kinetics in the surface reaction control stage. These insights into the synergistic promoted mechanism of nitrate and nitrite anion species is expected to provide guidance for the further design of the high performance MgO-based CO<sub>2</sub> adsorbent.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":null,"pages":null},"PeriodicalIF":8.1000,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A new explanation for the synergistic promoted mechanism of nitrate and nitrite anion species for the high performance MgO adsorbent\",\"authors\":\"Shuo Zhao, Panpan Wang, Hongxia Guo, Xiao Wang, Huan Wang, Wenquan Cui\",\"doi\":\"10.1016/j.seppur.2024.129971\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The mechanism of CO<sub>2</sub> capture on the nitrate and nitrite anion species synergistic promoted MgO has been rarely studied and still not fully understood. Herein we report a systematic investigation on the CO<sub>2</sub> adsorption performance of molten salts-promoted MgO adsorbent to deeply reveal the synergistic promoted mechanism of nitrate and nitrite. A series of MgO-based solid adsorbents were synthesized and applied for CO<sub>2</sub> capture using NaNO<sub>2</sub>/KNO<sub>3</sub> as promoters. The addition of mixed nitrate and nitrite promoters greatly enhances the adsorption capacity of MgO, exhibiting CO<sub>2</sub> capture up to 10.25 mmol·g<sup>−1</sup> under optimal conditions. The MgO-based adsorbent in the form of nanosheets has faster adsorption kinetics and better stability, and the possible reaction mechanism of MgO modified by nitrate and nitrite was proposed. Firstly, NO<sub>3</sub><sup>–</sup> interacts with the lattice oxygen (O<sub>1</sub><sup>2-</sup>) of MgO to form NO<sub>2</sub><sup>–</sup> and O<sub>2</sub><sup>2–</sup>. Secondly, Mg<sup>2+</sup> interacts with the free NO<sub>2</sub><sup>–</sup> to form [Mg···NO<sub>2</sub>]<sup>+</sup> and further overcomes the energy barrier to generate [Mg<sup>2+</sup>···O<sup>2–</sup>] ion pairs. O<sub>2</sub><sup>2–</sup> is not stable and prone to side reaction. However, NO<sub>2</sub><sup>–</sup> can be converted into O<sub>2</sub><sup>–</sup>, and O<sub>2</sub><sup>–</sup> is further generated to O<sub>2</sub><sup>2–</sup>, facilitating regeneration of NO<sub>3</sub><sup>–</sup>. The introduction of molten salt can significantly reduce the reaction energy barrier, and the energy barrier required to generate [Mg<sup>2+</sup>···O<sup>2–</sup>] ion pairs is reduced from 6.86 eV to 3.50 eV. Adsorption kinetics studies reveal that the nano-flake MgO facilitates the full contact with the promoter and has faster reaction kinetics in the surface reaction control stage. These insights into the synergistic promoted mechanism of nitrate and nitrite anion species is expected to provide guidance for the further design of the high performance MgO-based CO<sub>2</sub> adsorbent.\",\"PeriodicalId\":427,\"journal\":{\"name\":\"Separation and Purification Technology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":8.1000,\"publicationDate\":\"2024-10-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Separation and Purification Technology\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://doi.org/10.1016/j.seppur.2024.129971\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, CHEMICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Separation and Purification Technology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1016/j.seppur.2024.129971","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
A new explanation for the synergistic promoted mechanism of nitrate and nitrite anion species for the high performance MgO adsorbent
The mechanism of CO2 capture on the nitrate and nitrite anion species synergistic promoted MgO has been rarely studied and still not fully understood. Herein we report a systematic investigation on the CO2 adsorption performance of molten salts-promoted MgO adsorbent to deeply reveal the synergistic promoted mechanism of nitrate and nitrite. A series of MgO-based solid adsorbents were synthesized and applied for CO2 capture using NaNO2/KNO3 as promoters. The addition of mixed nitrate and nitrite promoters greatly enhances the adsorption capacity of MgO, exhibiting CO2 capture up to 10.25 mmol·g−1 under optimal conditions. The MgO-based adsorbent in the form of nanosheets has faster adsorption kinetics and better stability, and the possible reaction mechanism of MgO modified by nitrate and nitrite was proposed. Firstly, NO3– interacts with the lattice oxygen (O12-) of MgO to form NO2– and O22–. Secondly, Mg2+ interacts with the free NO2– to form [Mg···NO2]+ and further overcomes the energy barrier to generate [Mg2+···O2–] ion pairs. O22– is not stable and prone to side reaction. However, NO2– can be converted into O2–, and O2– is further generated to O22–, facilitating regeneration of NO3–. The introduction of molten salt can significantly reduce the reaction energy barrier, and the energy barrier required to generate [Mg2+···O2–] ion pairs is reduced from 6.86 eV to 3.50 eV. Adsorption kinetics studies reveal that the nano-flake MgO facilitates the full contact with the promoter and has faster reaction kinetics in the surface reaction control stage. These insights into the synergistic promoted mechanism of nitrate and nitrite anion species is expected to provide guidance for the further design of the high performance MgO-based CO2 adsorbent.
期刊介绍:
Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.