文章研究了复合金属氧化物(LDO)对水中苯甲酸钠的吸附热力学及其机理,测定了不同温度下的吸附等温曲线,计算了热力学函数;结果表明,在293-313K和实验浓度范围内,LDO对水中苯甲酸钠的吸附是自发的吸热过程,无配位基交换、化学键等强的作用力;吸附等温线符合Langmuir及Freundlich方程,吸附系数(K)与温度成负相关,吸附自由能的变小是苯甲酸钠在LDO上吸附的推动力,LDO吸附苯甲酸钠是一个熵增过程,吸附熵变为55.47J/(mol·K)。
The adsorption thermodynamics and mechanism of LDO for sodium benzoate(SB) from aqueous solution were investigated. The adsorption isotherms were measured at different temperatures, and the functions of thermodynamics were also calculated. The results indicate that the adsorption process of SB from aqueous solution on LDO is a spontaneous endothermic process within the temperature range 293-313 K and the SB mass concentration range in experiment and there exists no strong action force such as the concerted radical exchange and the chemical bond. The adsorption isotherm was correlated with the Langmuir and Freundlich-type isotherm equations well. The adsorption coefficient(K) was negatively correlated to temperature. The adsorption occurred because of the decrease of Gibbs free energy. The adsorption of SB on LDO was an entropy-increasing process and the adsorption entropy change was 55.47 J/(mol · K).