模拟酸雨对街道灰尘重金属淋溶的累积释放特征与释放模型  

Releasing characteristics and models of heavy metals from the street dust leached by simulated acid rain

作　　者：胡恭任[1] 于瑞莲[1] 刘海婷[1] 张雨婷[1] 

机构地区：[1]华侨大学环境科学与工程系,厦门361021

出　　处：《环境化学》2013年第5期886-892,共7页Environmental Chemistry

基　　金：福建省自然科学基金项目(2012J01176);泉州市科技计划重点项目(2012Z86);2012华侨大学学生科技文化创新项目(13)资助

摘　　要：以泉州市交通繁忙区街道灰尘为研究对象,采用模拟酸雨动态淋溶实验和改进的BCR四步提取法研究街道灰尘中重金属元素在不同酸度(pH=3.5、4.5、5.6)模拟酸雨淋溶下的溶出规律及形态变化.结果表明,街道灰尘中重金属元素的累积释放量均随模拟酸雨pH的降低而增加,当pH值为3.5和4.5时,Cu、Pb、Mn、Ni、V、As和Co的释放过程为快速释放阶段,Cr、Zn和Fe的释放过程分为快速释放和相对平稳释放两个阶段;当pH值为5.6时,除Co、V为快速释放过程外,其余重金属都处于相对慢速的释放过程.动力学方程拟合结果表明,双常数速率方程能更好地描述上述重金属元素的累积释放特征.尘样经模拟酸雨淋溶后,弱酸可溶态中Co、Cu、Mn、Zn、Ni百分含量有所增加,Cr、Fe、Pb百分含量变化不明显;可还原态中Cr、Pb、Cu、Ni百分含量有所增加,Mn、Zn、Co百分含量有所下降;可氧化态中上述各元素的百分含量均有所降低;残渣态中除Ni、Mn百分含量有所下降外,其它元素百分含量变化均不显著.Releasing characteristics and models of heavy metals in the street dust collected from heavy traffic area in Quanzhou city were investigated by dynamic leaching experiment with simulated acid rain at different pH （3.5, 4.5, 5.6 ）. Speciation transformation of heavy metals in the street dust before and after leaching experiment was also studied by using modified BCR-sequential extraction technique. The results showed that the total releasing contents of all the studied heavy metals increased with the decrease of pH value. Cu, Pb, Mn, Ni, V, As and Co presented rapid releasing processes, while Cr, Zn and Fe showed rapid and stable releasing processes when the pH was 3.5 and 4.5. When pH was 5.6, most of the studied heavy metals showed relatively slow releasing processes except Co and V. The fitted results of releasing process of heavy metals by using the dynamic equations showed that the double constant velocity equation was more suitable to describe the cumulative releasing characteristics of above heavy metals. After being leached by simulated acid rain, the percentage contents of Co, Cu, Mn, Zn and Ni increased while the percentage contents of Cr, Fe and Pb did not changed obviously in the acid-soluble fraction; In the reducible fraction, the percentage contents of Cr, Pb, Cu and Ni increased while the percentage contents of Mn, Zn and Co decreased; All the studied heavy metals in the oxidizable fraction decreased; Most of the studied heavy metals in the residual fraction did not change significantly except Ni and Mn decreased.

关 键 词：街道灰尘 重金属 模拟酸雨 淋溶 形态转化 

分 类 号：X517[环境科学与工程—环境工程]