超细粉煤灰对甲基橙的吸附性能和机理研究

Adsorption Capacity and Mechanism of Methyl Orange by Using Ultrafine Coal Fly Ash

以粉煤灰为原料,通过球磨制得超细粉煤灰,研究了其对水中偶氮染料甲基橙的吸附性能和机理。结果表明,在25℃,pH值为2,投加量为0.7g,反应时间为120min时,粉煤灰对甲基橙的去除率为79.4%,超细粉煤灰对甲基橙的去除率可达93.8%。随温度升高,吸附量降低,证明该吸附为放热过程,并计算不同温度下各热力学参数△G,△H和△S。对实验数据运用相关数学模型拟合,显示等温吸附平衡符合Freundlich吸附等温式,吸附过程动力学更适合二级吸附动力学模型。

Ultrafine coal fly ash was prepared by ball milling from raw coal fly ash. The adsorption capacity and mechanism of methyl orange adsorption onto coal fly ash were studied. Results showed that under the conditions of pH 2, adsorption temperature of 25℃, dosage of 0.7g and reaction time of 120min, removal efficiency was up to 93.8% for ultrafine coal fly ash, and about 79.4% for raw coal fly ash. Adsorption capacity decreased with increase of temperature indicated that adsorption was an exothermic process. Thermodynamic parameters were calculated, with the experimental data fitting by related mathematic models, which showed isotherm adsorption equilibrium fits Freundlich model, and adsorption process kinetics can be described by second-order reaction.