MCFs吸附茜素红S的研究

Adsorption of Alizarin Red S by MCFs

以水热法合成出介孔泡沫二氧化硅材料(MCFs),以MCFs吸附茜素红S得到最佳吸附条件,最大吸附容量为3.750 mg/g。从293.15~323.15 K温度区间获得了吸附体系的热力学性质,反应焓变△H0=48.038 k J/mol>0,说明MCFs吸附茜素红S的过程属于吸热反应。熵变△S0=243.3 J/(mol·K)>0,说明MCFs吸附茜素红S为熵增加过程。该温度区间吸附反应的自由能变化值△G0<0,该吸附处于自发反应,而且吸附反应同时伴随物理吸附和化学吸附。MCFs吸附茜素红S的过程符合动力学准二阶方程。Freundlich吸附等温方程拟合效果较之Langmuir更好,吸附结果符合Freundlich吸附等温线,该吸附过程属于多分子层吸附。

Mesocellular foams（ MCFs） silica was successfully synthesized by hydrothermal method. In this article,MCFs was used to adsorb alizarin red S and the optimum conditions of adsorption were obtained. The maximum capacity of adsorption was 3. 750 mg/g. The thermodynamic properties of adsorption system were obtained from a temperature range of 293. 15-323. 15 K. The reaction enthalpy△H^0= 48. 038 k J/mol 0,showed that process of the adsorption of alizarin red S by MCFs belongs to an endothermic reaction. The entropy change △S^0= 243. 3 J/（ mol·K） 0,indicated that the adsorption of alizarin red S by MCFs is a process of increase in entropy. Over the range of the temperature,the free energy change value △G^0of adsorption reaction is less than zero,the adsorption is a spontaneous reaction and the adsorption reaction is accompanied by physical adsorption and chemical adsorption. The process in which alizarin red S is adsorbed by MCFs accords with the dynamic quasi-two-order equation. The fitting effect of Freundlich isotherm equation was better than that of Langmuir isotherm equation,the results of adsorption accorded with the Freundlich adsorption isotherm,and the adsorption process belongs to a multiple molecular layer adsorption.