The methane adsorption properties of activated carbon samples from pinecones using chemical activation with different KOH/precursor ratio were estimated at room temperature (≅298 K) and pressure up to 35 bar using a volumetric Sievert-type apparatus. A complete and detailed characterization of the synthesized activated carbon samples was obtained using nitrogen adsorption/desorption measurements at liquid nitrogen temperature (77 K), for the textural properties analysis, by scanning electron microscopy and X-ray diffraction for topography and long-range order estimation, and by wavelenght-dispersive spectrometry for chemical composition, respectively. All the adsorption data were analyzed by the Tóth isotherm model. The probed activated carbon samples show both higher methane storage values for pressures up to 35 bar (the maximum value reached is 15 wt%) and totally reversible methane uptake up to many cycles without any treatment in between indication of very stable properties. The experimental work reported in this paper could represent a good alternative method to the natural gas storage through the use of eco-compatible nanostructured materials.

中文翻译：

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松果衍生活性炭中的低压甲烷储存

在室温（≅298K）和压力高达35 bar的条件下，使用容积式Sievert型仪器估算了使用不同KOH /前体比率进行化学活化的松果中活性炭样品的甲烷吸附特性。使用液氮温度（77 K）下的氮吸附/解吸测量获得合成的活性炭样品的完整和详细表征，用于结构特性分析，通过扫描电子显微镜和X射线衍射进行形貌和远距离有序分析估计和通过波长色散光谱法分别测定化学成分。所有吸附数据均通过Tóth等温线模型进行分析。探测到的活性炭样品在最高35 bar的压力下显示出更高的甲烷存储值（达到的最大值为15 wt％），并且在许多循环中完全可逆的甲烷吸收，并且在未经处理之间显示出非常稳定的性能。通过使用生态兼容的纳米结构材料，本文报道的实验工作可以代表天然气存储的一种很好的替代方法。