天然硅藻土吸附活性染料的热力学研究

The Thermodynamic Study on Adsorption of Reactive Dyes by Nature Diatomite

研究了天然硅藻土吸附水溶液中两种活性染料活性黑K-RB和活性金黄X-G的吸附特性。结果表明:两种活性染料平衡吸附量都随温度上升而上升,在相同条件下活性黑平衡吸附量大于活性金黄,染料分子的大小、官能团是影响吸附主要因素。两种染料吸附等温线均符合Langmuir和Freundlich方程,表明吸附主要是物理吸附,属于多层吸附。吸附是一个吸热反应ΔH>0,自发进行(ΔG<0),ΔS总是正值,此外,根据实验数据,计算了吸附势E,其值随吸附量增多而减小。

The adsorption capability of nature diatomite to reactive dyes （reactive black K - RB and reactive golden yellow X - G） in aqueous solution was studied. The results showed that the adsorption capacity （qe） of each dye increased with the temperature. On the same condition, the qe of reactive black was more than reactive golden yellow, and molecule size and functional groups of dyes were important factors to adsorption reaction. The two dyes adsorption on nature diatomite fitted well to Langmuir and Freundlich isotherm which indicated that it belonged to multilayer adsorption. It was mainly physical adsorption. The positive values of the adsorption enthalpy △H indicated the exotherrnic reaction. The negative adsorption Gibbs free energy changes △G indicated adsorption being spontaneous. △S was always positive. In addition, adsorption potential E which was calculated from the experimental data decreases as the adsorption capacity increasing.