Abstract This work aims to evaluate the performance of 3D graphene as the reusable adsorbent of synthetic dyes. For this, the behavior of 3D graphene samples in the adsorption of methyl orange (MO) dye from aqueous solutions as well as the thermal regeneration of the 3D graphene saturated with dye at various temperatures of 300–700 °C was studied. The 3D graphene before and after being thermally regenerated was characterized by various techniques including electron microscopy, thermal analysis, nitrogen adsorption, X-ray diffraction (XRD) and Raman spectroscopy. A simple heat treatment process was employed as a low cost and fast regeneration strategy, resulting in efficient recovery of the 3D graphene, with a remarkable structural and morphological stability over the whole adsorption and thermal regeneration process. Thermal regeneration proved to be an efficient process to remove the MO content adsorbed on the exhausted 3D graphene, providing an adsorption capacity equals to 77–94% of the original 3D graphene for the samples regenerated at different temperatures. The decomposition of MO was further investigated by thermal analysis and liquid chromatography- mass spectrometry demonstrating that the dye is decomposed below 300 °C, leaving inorganic salts behind.

中文翻译：

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热再生过程中甲基橙染料饱和的介孔 3D 石墨烯的纹理、结构和形态演变

摘要 这项工作旨在评估 3D 石墨烯作为可重复使用的合成染料吸附剂的性能。为此，研究了 3D 石墨烯样品从水溶液中吸附甲基橙 (MO) 染料的行为，以及在 300-700 °C 的不同温度下用染料饱和的 3D 石墨烯的热再生。通过电子显微镜、热分析、氮吸附、X射线衍射（XRD）和拉曼光谱等多种技术对热再生前后的3D石墨烯进行表征。采用简单的热处理工艺作为低成本和快速再生策略，可有效回收 3D 石墨烯，在整个吸附和热再生过程中具有显着的结构和形态稳定性。热再生被证明是去除吸附在耗尽的 3D 石墨烯上的 MO 含量的有效过程，为在不同温度下再生的样品提供等于原始 3D 石墨烯的 77-94% 的吸附容量。通过热分析和液相色谱-质谱法进一步研究了 MO 的分解，证明染料在 300°C 以下分解，留下无机盐。