Metal–organic frameworks (MOFs) have attracted considerable attention for selective deep removal of refractory sulfur compounds from fuels. In this work, cobalt-based MOFs (nanocrystals of Co-ZIF-67) were successfully prepared to find a capable adsorbent for removal of dibenzothiophene (DBT) from fuel. This paper revealed the main importance of preparation conditions in adjusting the surface area and pore structure of Co-ZIF-67 crystals for DBT adsorption purposes. Several methods including XRD, SEM, TEM, FTIR, TGA, BET, BJH, and N₂ adsorption–desorption were used for characterization of the prepared adsorbents. Screening the adsorbents demonstrated the proper structure and performance of Co-ZIF-67/M nanocrystals synthesized by methanol at room temperature. A considerable promotion in DBT adsorption ability was further reached through exposing more active centers by surface activation. By employing activated Co-ZIF-67/M-A1 (S_BET = 2478.8 m²/g), a maximum adsorption capacity of 550 mg/g was attained at T = 65 °C and M_adsorbent/V_fuel = 0.8 mg/mL, with an excellent reusability of the adsorbent in four repeated uses. The endothermic nature of DBT adsorption was verified by the positive influence of temperature. A good fitting of experimental data with Langmuir–Freundlich isotherm expressed a possible combination of monolayer and multilayer adsorption of DBT. The kinetic and mechanism studies were also conducted, and possible adsorption pathways were suggested.

中文翻译：

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一种高效的基于钴的金属-有机骨架纳米晶体（Co-ZIF-67），用于二苯并噻吩的吸附脱硫：制备方法对结构调整的影响

金属有机框架（MOF）在从燃料中选择性地深度去除耐火硫化合物方面引起了极大的关注。在这项工作中，成功制备了钴基MOF（Co-ZIF-67的纳米晶体），以找到一种能从燃料中去除二苯并噻吩（DBT）的有效吸附剂。本文揭示了制备条件对于调节DBT吸附目的Co-ZIF-67晶体的表面积和孔结构的重要性。几种方法，包括XRD，SEM，TEM，FTIR，TGA，BET，BJH和N ₂吸附-解吸用于表征所制备的吸附剂。筛选吸附剂证明了在室温下甲醇合成的Co-ZIF-67 / M纳米晶体的适当结构和性能。通过表面活化暴露更多的活性中心，进一步提高了DBT吸附能力。通过使用活化的Co-ZIF-67 / M-A1（S _BET = 2478.8 m ² / g），在T = 65°C和M_吸附剂/ V_燃料时，最大吸附容量为550 mg / g。= 0.8 mg / mL，在四次重复使用中具有极好的吸附剂重用性。温度的积极影响证实了DBT吸附的吸热特性。Langmuir-Freundlich等温线的实验数据很好拟合，表明DBT的单层吸附和多层吸附是可能的组合。还进行了动力学和机理研究，并提出了可能的吸附途径。