不同环境条件下粉煤灰吸附铅离子效率对比研究

以粉煤灰为吸附材料,利用硝酸铅试剂模拟含铅离子废水,探讨了吸附时间、pH、温度、投灰量、离子浓度5个因素对粉煤灰吸附铅离子效率的影响,并拟合出不同条件下的最佳吸附模型.单因素分析结果表明,当实验条件分别为吸附时间90min、pH=6.0、温度50℃、投灰量5.0g、离子浓度30mg/L时吸附效果最好,吸附效率均超过98%.吸附时间、pH值、投灰量3种影响因子所建立的粉煤灰吸附铅离子方程均以二次多项式表示为最佳,回归系数R~2均超过0.83,而温度和离子浓度所建立的方程中,前者以三次多项式精度最高,R~2可达0.86;后者则以对数形式拟合最好,R~2为0.93.实验中拟合粉煤灰吸附铅离子过程Langmuir模型的R~2比Freundich模型的R~2大0.602,所以其更适用于Langmuir单分子层吸附模型.

Fly ash adsorption efficiency of lead ions under different environmental conditions

Taking advantage of lead nitrate reagent simulated as wastewater containing lead ion,this used fly ash as the adsorption material.The purpose of this study is evaluating the influence of efficiency of lead ion absorption about five factors,such as adsorption time,pH,temperature,ash content and ion concentration,and fitting out the best adsorption model under different conditions.The result of single factor analysis showed that the efficiency of adsorption was the best in the experimental condition of 90 min adsorption time,pH=6.0,50 ℃,5.0 g fly ash or 30 mg/L ion concentration,which was more than 98%.The best fly ash adsorption equation was modeled by adsorption time,pH,ash content as quadratic polynomial,and regression coefficient R~2 were all more than 0.83.The highest precision of temperature equation was using the form of cubic polynomial,regression coefficient R~2 was 0.86;and the equation of ion concentration fit in logarithmic form was the best and the value of R~2 was 0.93.In the experiment,the value of R~2 of the Langmuir model was more than Freundich model of 0.602,so the Langmuir monolayer adsorption model was more suitable for process of absorbing lead ion.