有序介孔炭吸附萘的研究

Study on Adsorption of Naphthalene on Ordered Mesoporous Carbons

采用溶剂挥发诱导自组装合成了有序介孔炭(OMC)。XRD和N2吸附测试表明,OMC具有有序的二维六方结构,平均孔径为3.4nm,比表面积为504.9m2.g-1,介孔率为67.6%。研究了OMC对萘的吸附机理,萘在OMC表面的吸附等温线表明,OMC对萘的吸附符合Langmuir吸附等温规律。由Vant Hoff方程计算得出OMC对萘的吸附焓变为-24.83kJ·mol-1,说明吸附为放热过程,推测其吸附机理为氢键作用力。红外光谱分析进一步证明,萘与OMC表面之间主要以氢键作用产生吸附。吸附温度的升高使-OH伸缩振动峰的红移程度减小,氢键缔合作用力减弱,这可能是导致温度升高时OMC的萘平衡吸附量减小的主要原因。

Ordered mesoporous carbons （OMC） were prepared by evaporation induced self-assembly method. It was found that OMC possessed 2D hexagonal structure by XRD patterns and nitrogen adsorption showed the average pore diameter was 3.4 nm, the SBET was 504. 9 m^2·g^-1 and the ratio of mesoporous volume to total pore volume reached 67.6 %. The adsorption mechanism of naphthalene on OMC was investigated. The adsorption isotherms fitted the Langmuir Model well. The adsorption enthalpy （△H0）, which was calculated from the Vant Hoff equation, was -24. 83 kJ · mol^-1 ,indicating that the adsorption process was exothermic, and the adsorption mechanism presumed to be hydrogen bonding adsorption. Furthermore, the interaction between naphthalene and OMC was mainly through hydrogen bond, which was proved by FTIR. As the temperature in- creased, the red-shift extent decreased, so the hydrogen bonding interaction weakened. This might explain the fact that the equilibrium adsorption capacity of naphthalene on OMC reduced with the temperature increasing.