痕量K元素对煤基碳材料NO_(x)低温吸附功能的影响机理

Influence mechanism of trace K element on NO_(x) adsorption of coal-based carbon materials at low temperature

本研究选取准东煤为碳材料前驱体,以水热耦合痕量K元素的方法对其进行活化。通过实验探究K质量浓度对碳吸附性能的影响,同时系统研究了材料的NO_(x)低温吸附性能。实验结果表明,活化液中K_(2)CO_(3)质量浓度为0.0067 g/mL时,所制得的样品对NO_(x)的吸附性能较好,其饱和NO_(x)吸附时间为3200 s。通过低温N_(2)物理吸附研究发现,该质量浓度下样品的孔结构发展较好,比表面积达到708.6 m^(2)/g。此外,本研究通过XPS、SEM等手段对不同质量浓度K_(2)CO_(3)活化的碳基材料进行了物化表征,并对不同质量浓度K_(2)CO_(3)活化制备的样品进行了表面性质分析,通过FT-IR对样品表面的吸附过程进行研究,发现准东煤基碳材料优良的吸附性能与表面结构相关,研究中采用DFT手段对反应机理进行验证,结果表明,K可促进C−O键的形成,而活性C−O结构是促进NO_(x)吸附的关键因素。通过该系列实验,本工作获得采用水热耦合痕量K元素制备准东煤基碳材料的最佳方法和最优工艺参数。

In this paper,Zhundong coal was used as the precursor of carbon material followed by activation by hydrothermal coupling with trace amount of K element.The influence of K concentration on the adsorption performance of as-prepared carbon material of NO_(x)at low temperature was studied.The experimental results showed that when the concentration of K_(2)CO_(3)in the activation solution was 0.0067 g/mL,the sample had good NO_(x)adsorption performance,and the saturated NO_(x)adsorption time was 3200 s.The pore structure of the sample developed well with the specific surface area of 708.6 m^(2)/g.The samples were characterized by XPS,SEM and the adsorption process was studied by FT-IR.It was found that excellent adsorption properties of Zhundong coal derived carbon material were related with the surface structure.DFT method was employed to verify the reaction mechanism.The results showed that K could promote the formation of C–O bond which was the key factor for promoting the NO_(x)adsorption.The best method and optimal process parameters for preparing Zhundong coal-based carbon materials by hydrothermal coupling with trace amount of K were obtained.