粉煤灰对废水中铜的高效吸附模型及实验研究

Efficient adsorption model and experimental study of fly ash on copper in wastewater

以工业废弃物粉煤灰为吸附剂,采用常规吸附和高效吸附工艺去除废水中的铜。当初始铜浓度10 mg/L,粉煤灰投加量0.5 g/L时,反应20 min可达吸附平衡,吸附量为15.58 mg/g,解吸附率仅为0.12%,且吸附过程符合Langmuir吸附等温式。基于以上特征,建立了高效吸附工艺的数学模型,通过响应曲面实验获得模型参数并进行实验验证。高效吸附实验结果表明:10个周期的出水铜浓度基本保持恒定,模型的计算值与实验值吻合较好,说明该模型可较准确的预测出水铜浓度。工艺的滞留因子越小,铜浓度越低。当滞留因子为0.25时,粉煤灰对铜吸附量为19.62 mg/g,与传统吸附相比提高了25.9%。

The industrial waste fly ash was used as an adsorbent to remove copper from wastewater with the convention-al adsorption and efficiency adsorption processes.Adsorption equilibrium can be reached after 20 minutes of adsorption with the initial copper concentration of 10 mg/L and the fly ash dosage of 0.5 g/L.The adsorption capacity was 15.58 mg/g,the desorption rate is only 0.12%,and the adsorption process conforms to the Langmuir adsorption isotherm.Based on these characteristics,a mathematical model of effective adsorption process was established.The model parameters were obtained through response surface experiments and verified by experiments.Efficient adsorption experiment results showed that the copper concentrations in the effluent kept constant within 10 cycles.The calculated values of the model were in good agreement with the experimental ones indicating that the model can accurately predict the copper concentra-tion in the effluent.The smaller the retention factor of the process is,the lower the copper concentration is.The adsorp-tion capacity reached 19.62 mg/g with the retention factor is 0.25.Compared with the conventional adsorption,the ad-sorption capacity increased by 25.9%.