Abstract In this work, a highly efficient adsorbent consisting of the ZnO/Graphene composite was prepared for the first time via the sonification route using urea as an alkaline precursor. The synthesized ZnO/Graphene composite provides the highest specific surface area comparing to other ZnO/Graphene composites synthesized by different approaches presented in the literature. For all we know, this is the first time the obtained ZnO/Graphene composite was used as an adsorbent for the transformer oil purification. The results showed that the ZnO/Graphene composite has a higher purification capacity than the conventional adsorbent, a commercial zeolite. Several factors that may underpin this outstanding result, such as the unreduced oxygen functional groups, the vacancy defects on the surface of the RGO flake, the high specific surface area, and the suitable pore size of the ZnO/Graphene composite for oil refining. Besides, the 3D structure of the ZnO/Graphene composite can enlarge the residence purification time of the transformer oil, helping to improve the purification capacity of the ZnO/Graphene composite.

中文翻译：

---

ZnO/石墨烯复合材料净化变压器油的高效吸附剂

摘要 在这项工作中，首次以尿素为碱性前驱体，通过超声途径制备了一种由 ZnO/石墨烯复合材料组成的高效吸附剂。与通过文献中提出的不同方法合成的其他 ZnO/石墨烯复合材料相比，合成的 ZnO/石墨烯复合材料提供了最高的比表面积。据我们所知，这是第一次将获得的 ZnO/石墨烯复合材料用作变压器油净化的吸附剂。结果表明，ZnO/石墨烯复合材料具有比传统吸附剂（一种商业沸石）更高的净化能力。可能支持这一出色结果的几个因素，例如未还原的氧官能团、RGO 薄片表面的空位缺陷、高比表面积、以及用于炼油的 ZnO/石墨烯复合材料的合适孔径。此外，ZnO/石墨烯复合材料的3D结构可以延长变压器油的停留净化时间，有助于提高ZnO/石墨烯复合材料的净化能力。