铅在城市植被过滤带中的吸附与解吸附

Adsorption and Desorption of Lead in Grass in Urban Vegetation Filtration Zone

环境污染日益严重,水生态问题频现,海绵城市应运而生,城市植被过滤带发挥重要作用,包括蓄积雨水和吸附污染物。汽车尾气中铅微粒随风扩散流入环境,造成严重污染,城市植被过滤带吸附后是否会解吸附造成二次污染有待探究。该文采用实验结合模型的方法探讨城市植被过滤带中草体对铅的吸附和解吸附规律。结果表明,草体对高浓度铅比低浓度吸附效果更好,pH为5.0时去除铅最多,自来水对铅的洗脱能力很差,自然状态下不会造成铅解吸附形成二次污染,平衡时吸附数据用Langmuir吸附等可拟合出草体对铅的吸附容量。实验结果为利用城市植被过滤带去除汽车尾气污染物提供理论依据。

Environmental pollution is becoming more and more serious,water ecological problems are frequent,sponge city arises at the historic moment,and urban vegetation filter belt plays an important role.Lead particles in automobile exhaust diffuse into the environment with the wind,causing serious pollution.Therefore,this paper uses the method of controlling variables to explore the influencing factors of lead adsorption by grass in urban vegetation filter belt and whether grass will desorb lead and form secondary pollution.The results showed that the adsorption capacity of straw for high concentration lead is greater than that for low concentration lead.The highest amount of lead is removed when pH is 5.0,and 0.1 mol/L dilute sulfuric acid has the best elution capacity.Therefore,lead desorption will not cause secondary pollution under natural conditions.The adsorption data at equilibrium are well fitted by Langmuir adsorption isotherm.The experimental results provide theoretical basis for the treatment of automobile exhaust pollutants by using urban vegetation filter belts.