粉煤灰吸附去除城市景观水体中磷的初步研究

研究了三种常见的中、低钙粉煤灰的磷吸附特性。研究表明:吸附反应均符合Langmuir方程,吸附容量分别达到20.49、23.15和6.54 mg/g。30min之内均可达到磷吸附平衡,灰水比对磷吸附效果有较大影响。三种粉煤灰对模拟景观水体中磷的去除下限分别为0.02、0.01、0.30mg/L,在此下限以上,随着原水磷浓度的增加,磷的去除率升高,最高可达99.99%;在此下限以下则出现粉煤灰中磷溶出的现象。对城市景观水体的磷吸附实验表明,粉煤灰对总磷(TP)为0.14mg/L、可溶性磷酸盐(DP)为0.02mg/L的轻度富营养化水体中DP没有去除效果。对TP为0.73mg/L、DP为0.40mg/L的重度富营养化水体,DP的去除率分别为77.39%、88.30%和1.98%。实验结果表明,钙含量较高、磷吸附容量大的粉煤灰在处理磷含量相对较高、富营养化较严重的城市景观水体领域有着良好的应用前景。

Preliminary Study on Phosphorus Removal from Urban Landscape Water by Fly Ash

Characteristics of phosphorus adsorption in urban landscape water by three types of fly ash were studied. Results showed that the adsorption was in accordance with Langmuir equation with adsorption capacity of 20.49 mg/g, 23.15 mg/g and 6.54 mg/g respectively. Kinetic parameters of adsorption indicated that the adsorption reached its balance point within 30 minutes and removal efficiency was closely concerned with the dosage of fly ash. Experiment for phosphorus removal in synthetic urban landscape water showed that removal efficiency increased with the rise of phosphorus concentration in the influent, and the highest removal efficiency was 99.99%. Experiment for phosphorus removal in raw urban landscape water showed that these types of fly ashes were inefficient in removing TP from micro-eutrophic water of TP 0.14 mg/L and DP 0.02 mg/L, while the TP removal efficiency for severe-eutrophic water of TP 0.73 mg/L and DP 0.40 mg/L were 77.39%, 88.30% and 1.98% respectively. It is concluded that fly ash with high content of CaO is promising in the field of treating severe-eutrophic urban landscape water.