粉煤灰及其制备沸石对高浓度氨氮的去除比较

以粉煤灰为原料,采用改进的水热合成法制备了粉煤灰沸石,并将粉煤灰和粉煤灰沸石用于高浓度氨氮的吸附去除。实验结果表明:在粉煤灰和粉煤灰沸石的投加量分别为0.10 g/m L和0.04 g/m L、反应体系p H为5~7、初始氨氮质量浓度为500 mg/L的条件下,分别吸附660 min和60 min,粉煤灰和粉煤灰沸石对氨氮的去除率分别约为20.1%和50.7%左右,粉煤灰沸石对高浓度氨氮的去除效果明显优于粉煤灰;粉煤灰和粉煤灰沸石对氨氮的吸附动力学行为符合准二级动力学方程;Langmuir和Freundlich等温吸附模型能较好地描述粉煤灰对氨氮的等温吸附过程,而粉煤灰沸石对氨氮的等温吸附过程则更适宜用线性模型和Freundlich模型描述。

Comparison of High-Concentration Ammonia Nitrogen Removal Effects Between Fly Ash and Zeolite from Fly Ash

The zeolite was prepared by hydrothermal method using fly ash as raw material，and boty of them were used in adsorption of high-concentration ammonia nitrogen. The experimental results show that：Under the conditions of fly ash dosage and zeolite from fly ash dosage 0.10 g/mL and 0.04 g/mL respectively，reaction system pH 5-7 and initial ammonia nitrogen mass concentration 500 mg/L，adsorption time 660 min and 60 min respectively，the removal rates of ammonia nitrogen on fly ash and zeolite from fly ash are 20.1% and 50.7% respectively，which indicates that the ammonia nitrogen removal effect of zeolite from fly ash is more better than that of fly ash；The adsorption processes of ammonia nitrogen on fly ash and zeolite from fly ash are fitted with the pseudo-second-order kinetics equation；The ammonia nitrogen isotherm adsorption on fly ash can be well described with Langmuir model and Freundlich model，and the ammonia nitrogen isotherm adsorption on zeolite from fly ash can be well described with linear model and Freundlich model.