Abstract

In the present research, piperazine grafted-reduced graphene oxide RGO-N-(piperazine) was synthesized through a three-step reaction and employed as a highly efficient nanoadsorbent for H₂S gas removal. Temperature optimization within the range of 30–90 °C was set which significantly improved the adsorption capacity of the nanoadsorbent. The operational conditions including the initial concentration of H₂S (60,000 ppm) with CH₄ (15 vol%), H₂O (10 vol%), O₂ (3 vol%) and the rest by helium gas and gas hour space velocity (GHSV) 4000–6000 h⁻¹ were examined on adsorption capacity. The results of the removal of H₂S after 180 min by RGO-N-(piperazine), reduced graphene oxide (RGO), and graphene oxide (GO) were reported as 99.71, 99.18, and 99.38, respectively. Also, the output concentration of H₂S after 180 min by RGO-N-(piperazine), RGO, and GO was found to be 170, 488, and 369 ppm, respectively. Both chemisorption and physisorption are suggested as mechanism in which the chemisorption is based on an acid–base reaction between H₂S and amine, epoxy, hydroxyl functional groups on the surface of RGO-N-(piperazine), GO, and RGO. The piperazine augmentation of removal percentage can be attributed to the presence of amine functional groups in the case of RGO-N-(piperazine) versus RGO and GO. Finally, analyses of the equilibrium models used to describe the experimental data showed that the three-parameter isotherm equations Toth and Sips provided slightly better fits compared to the three-parameter isotherms.

Graphic Abstract

中文翻译：

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用哌嗪作为新型纳米吸附剂对还原型氧化石墨烯进行共价改性，以去除H 2 S气体

摘要

在本研究中，通过三步反应合成了哌嗪接枝还原氧化石墨烯RGO-N-（哌嗪），并用作高效的H ₂ S气体去除纳米吸附剂。设定的温度优化范围为30–90°C，这可以显着提高纳米吸附剂的吸附能力。操作条件包括初始浓度的H ₂ S（60,000 ppm）和CH ₄（15体积％），H ₂ O（10体积％），O ₂（3体积％），其余的氦气和气时空研究了在4000–6000 h ^-1速度下（GHSV）的吸附容量。除去H _2的结果RGO-N-（哌嗪）在180分钟后的S值分别为99.71、99.18和99.38，分别是还原型氧化石墨烯（RGO）和氧化石墨烯（GO）。此外，发现RGO-N-（哌嗪），RGO和GO在180分钟后的H ₂ S输出浓度分别为170、488和369 ppm。化学吸附和物理吸附均被认为是化学吸附基于H ₂之间的酸碱反应的机理。R和RGO-N-（哌嗪），GO和RGO表面上的S和胺，环氧，羟基官能团。在RGO-N-（哌嗪）相对于RGO和GO的情况下，哌嗪增加去除百分率可归因于胺官能团的存在。最后，对用于描述实验数据的平衡模型的分析表明，与三参数等温线相比，三参数等温线方程Toth和Sips提供了更好的拟合度。

图形摘要