The influence of heavy metals in road dust on the surface runoff quality: Kinetic, isotherm, and sequential extraction investigations
The influence of heavy metals in road dust on the surface runoff quality: Kinetic, isotherm, and sequential extraction investigations
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道路灰尘中重金属对地表径流质量的影响：动力学、等温线和顺序提取研究
DOI：
10.1016/j.ecoenv.2019.03.106
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发表时间：
2019
影响因子：
6.8
通讯作者：
Hua Pei
中科院分区：
文献类型：
--
作者：
Zhang Jin;Wang Xun;Zhu Yu;Huang Zhenyu;Yu Zhujing;Bai Yun;Fan Gongduan;Wang Peng;Chen Hao;Su Yiming;Trujillo-Gonzalez Juan Manuel;Hu Bill X.;Krebs Peter;Hua Pei
从雨水综合管理的角度研究了道路灰尘对重金属的吸附和解吸特性。铜，锌，镍，镉的化学分馏测定的三步连续提取协议。采用准一级和准二级反应动力学模型，沿着Langmuir、Freundlich和Temkin等温式对间歇实验数据进行拟合。测定了金属在原始RD、吸附平衡和解吸平衡中的化学分馏比例的变化。结果表明，RD对重金属离子具有较强的吸附能力，吸附时间短。吸附过程符合准二级动力学模型（R2= 0.98-0.99）和Freundlich等温式（R2= 0.89-0.98），表明化学吸附可能是速率控制步骤，且各吸附位点的结合能不同。对Cu、Cd、Zn和Ni的最大吸附容量分别为6300 mg kg−1、5800 mg kg−1、4000 mg kg−1和3200 mg kg−1。平衡pH值和吸附金属总量的线性拟合表明强pH依赖性吸附。根据重金属化学形态在吸附和解吸过程中的比例变化，RD中重金属的可交换态是不可逆的。这表明RD的一部分表面位一旦被占据，将是不可交换的。
This study examines the adsorption and desorption characteristics of heavy metals in road dust (RD) for the aspect of integrated stormwater management. The chemical fractionations of Cu, Zn, Ni, and Cd were determined by a three-step sequential extraction protocol. Pseudo-first-order and Pseudo-second-order kinetic models, along with Langmuir, Freundlich, and Temkin isotherms were adopted to simulate the batch experimental data. The proportional shift of metals' chemical fractionations in original RD, adsorption equilibrium, and desorption equilibrium were determined. Results show that RD has a remarkable affinity to adsorb heavy metal within a short time. The adsorption processes were well described by the Pseudo-second-order kinetic model (R2= 0.98–0.99) and Freundlich isotherm (R2= 0.89–0.98) for most of the given metals indicating that the chemical adsorption was probably the rate-controlling step and the binding energy for each site was not identical. The maximum adsorption capacities for Cu, Cd, Zn, and Ni were 6300 mg kg−1, 5800 mg kg−1, 4000 mg kg−1, and 3200 mg kg−1, respectively. A linear fit to the equilibrium pH and the total amounts of the adsorbed metals indicates a strong pH-dependent adsorption. According to the proportional shift of metals’ chemical fractionations during the adsorption and desorption processes, the exchangeable fractions of heavy metals in RD were irreversible. It suggests that a portion of the surface sites of RD would be not exchangeable once it was occupied.