Bläker Christian, Jähnichen Tim, Hojak Jan, Gehrke Laura, Pasel Christoph, Paschke Thomas, Dreisbach Frieder, Enke Dirk, Bathen Dieter
Chair of Thermal Process Engineering, University of Duisburg-Essen, Duisburg 47057, Germany.
Institute of Chemical Technology, Leipzig University, Leipzig 04103, Germany.
ACS Omega. 2024 Oct 11;9(42):42721-42733. doi: 10.1021/acsomega.4c02625. eCollection 2024 Oct 22.
Porous boron nitrides possess beneficial properties such as high thermal and chemical stability which are critical for applications in adsorption processes. In order to assess possible fields of applications, trace-level adsorption isotherms of different hydrocarbons on two synthesized porous boron nitrides and two commercial activated carbons are compared. By normalizing the adsorptive loadings on the micropore surface area, superior adsorption performances of the BN materials on polar and aromatic adsorptives with up to 50% higher loadings compared to the activated carbons can be shown. Nonpolar adsorptives, on the other hand, feature higher specific loadings on the activated carbon. Consequently, the size of the micropore surface appears to be decisive for nonpolar adsorptives, while the higher polarity of the boron nitrides is the dominant influencing factor for the adsorption of polar and aromatic components. For an energetic study of the adsorbents, calorimetric experiments were performed to identify and discuss adsorbent-adsorptive interactions. While the initial heat of adsorption of the nonpolar -hexane is lower on the boron nitride than on the activated carbon due to a less favorable spatial arrangement, toluene shows comparable values on both adsorbent classes and the polar acetone shows higher values on the polar boron nitride. Considering technical applications in adsorption technology, the thermal stability of the boron nitrides is investigated using spontaneous ignition temperatures and points of initial oxidation. Here, the porous boron nitrides with oxidation temperatures above 900 °C show about 400 °C higher values and thus a significantly higher thermal stability.
多孔氮化硼具有诸如高热稳定性和化学稳定性等有益特性，这些特性对于吸附过程中的应用至关重要。为了评估可能的应用领域，比较了两种合成的多孔氮化硼和两种商业活性炭对不同碳氢化合物的痕量吸附等温线。通过将微孔表面积上的吸附负载归一化，可以显示出BN材料对极性和芳香族吸附剂的优异吸附性能，其负载量比活性炭高50%。另一方面，非极性吸附剂在活性炭上具有更高的比负载量。因此，微孔表面的大小似乎对非极性吸附剂起决定性作用，而氮化硼较高的极性是极性和芳香族成分吸附的主要影响因素。为了对吸附剂进行能量研究，进行了量热实验以识别和讨论吸附剂与吸附质之间的相互作用。虽然由于空间排列不太有利，非极性己烷在氮化硼上的初始吸附热低于活性炭，但甲苯在两种吸附剂类别上显示出可比的值，而极性丙酮在极性氮化硼上显示出更高的值。考虑到吸附技术中的技术应用，使用自燃温度和初始氧化点研究了氮化硼的热稳定性。在此，氧化温度高于900°C的多孔氮化硼显示出约400°C更高的值，因此具有明显更高的热稳定性。
