由粉煤灰合成单一的沸石及其对Cr(Ⅵ)的吸附研究

Study on adsorption of Cr(Ⅵ) using single-phase zeolites synthesized from fly ash

以粉煤灰为原料采用两步法合成了2种单一沸石矿物种的NaA和NaX型沸石,并对产物的结构和性能进行了详细表征。2种沸石产物的吸附性能比较结果表明,NaA型沸石优于NaX型沸石。在静态吸附条件下,研究了NaA型沸石吸附水溶液中Cr(Ⅵ)的相关参数(溶液pH值、吸附温度和吸附时间),并用Langmuir和Freundlich等温吸附线对吸附结果进行拟和。结果表明:Cr(Ⅵ)的吸附行为符合Langmuir方程;饱和吸附量为47.78 mg/g。NaA型沸石对Cr(Ⅵ)的吸附是物理和化学吸附两种行为共同作用的结果。

Single-phase zeolites NaA and NaX were synthesized from fly ash using twostage method. The products were characterized in detail from structure and performance. Comparative adsorption of both zeolite shows that zeolite NaA exhibits much higher adsorption capacity compared with zeolite NaX. Under static adsorption conditions, relative parameters, such as pH value, temperature and time, were investigated for adsorption of Cr（Ⅵ） on zeolites NaA. The adsorption isotherm could be fitted by Langmuir and Freundlich models while the Langmuir model produces the best results. The greatest adsorption capacity of Cr（Ⅵ） is 4778 mg/g. The adsorption behavior of Cr（Ⅵ） using zeolite NaA shows the common effect of physical and chemical adsorption.