粉煤灰合成沸石对Cr~(3+)的去除能力及影响因素研究

研究了粉煤灰合成沸石对废水中Cr~(3+)的去除能力,分析了接触时间、pH、沸石投加量、Cr~(3+)初始浓度、温度等因素对Cr~(3+)过程吸附的影响.试验结果表明,合成沸石的主要成分为一种无名沸石.合成沸石对Cr~(3+)具有较快的吸附速度,吸附过程符合二级反应动力学.在pH 2.0~12.0范围内,合成沸石对Cr~(3+)都具有较高的去除效率.Cr~(3+)去除率随着沸石投加量的增加而增加,随着Cr~(3+)初始浓度的升高而降低.Langmuir等温线模型对吸附数据具有更好的非线性拟合效果,所得最大吸附量为111.7 mg·g-1.热力学研究表明吸附过程为吸热反应.与原沸石相比,利用Na Cl再生后的沸石的Cr~(3+)去除率下降11.42%~14.10%,但仍可循环利用.上述实验结果表明本文合成的沸石具有较好的除Cr~(3+)的应用潜力.

The ability and influencing factors of Cr3+ removal using synthetic zeolite from fly ash

This paper studied the capacity of synthesized zeolite from fly ash for Cr³⁺ removal in wastewater, and analyzed the influence of contact time, pH, zeolite dosage, initial concentration of Cr³⁺, temperature on the Cr³⁺ adsorption process by batch experiments. The results showed that the main component of the synthesized zeolite is an unnamed zeolite. The uptake of Cr³⁺ on the synthesized zeolite was relatively fast, and the process followed pseudo-second-order model. Within the range of pH 2.0~12.0, the synthesized zeolite had high Cr³⁺ removal efficiency. The Cr³⁺removal efficiency improved with the increase of zeolite dosage and decrease with the initial Cr³⁺ concentration. The Langmuir model can better characterize the adsorption equilibrium data,and the maximum adsorption capacity was 111.655 mg·g^-1. The adsorption process was also found to be endothermic reaction. Compared to the synthesized zeolite, the Cr³⁺ removal efficiency of zeolite regenerated using NaCl decreased by 11.42%~14.1%, but the regenerated zeolite could still be repeatedly used for Cr³⁺ removal. These results showed that the synthesized zeolite had a strong potential for Cr³⁺ removal.