Trace metal sorption by natural particles and coarse colloids
Trace metal sorption by natural particles and coarse colloids
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DOI：
10.1016/s0016-7037(99)00006-x
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发表时间：
1999-06
影响因子：
5
通讯作者：
J. Lead;J. Hamilton-Taylor;W. Davison;Michael P. Harper
中科院分区：
文献类型：
--
作者：
J. Lead;J. Hamilton-Taylor;W. Davison;Michael P. Harper
本文研究了粒径和地球化学性质对痕量金属与天然胶体和颗粒结合的影响。用离心法将英格兰西北部默西河的悬浮颗粒物（SPM）分成3个粒径级（标称0.05-0.5 μm、0.5-1.0 μm和>1.0 μm）。扫描电子显微镜和碳氮分析的SPM，其特征在于。大部分的颗粒是微生物的起源，占主导地位的硅藻在最大的尺寸部分和细菌的所有部分。酸碱滴定表明三种样品的质子结合特性之间存在显着差异。最小的部分具有最大的单位质量电荷，而最大的部分具有最小的电荷：在pH 4和10之间分别产生2.0和1.0 meq g− 1电荷。实验吸附研究表明，与镉和铜的金属结合每单位质量的SPM之间的三个大小的馏分变化不大，虽然镉是更强烈地结合到两个最小的馏分。一个简单的一个网站的结合模型提供了一个很好的描述的数据，并表明，所观察到的镉和铜的吸附常数与文献值是一致的。研究结果表明，金属结合到三个尺寸级分主要由质量浓度和pH值控制。对质量的依赖性表明，有效结合的表面积基本上是独立的大小类。结果的问题所发挥的作用的亚微米级的微量金属结合自然颗粒组合的重要性。
The effects of size and geochemical properties on the binding of trace metals to natural colloids and particles have been investigated. Suspended particulate matter (SPM) from the River Mersey in NW England was fractionated by centrifugation to give three size fractions (nominally 0.05–0.5 μm, 0.5–1.0 μm and >1.0 μm). The SPM was characterized by scanning electron microscopy and by carbon and nitrogen analysis. Large proportions of the particles were microbial in origin, dominated by diatoms in the largest size fraction and bacteria in all fractions. Acid-base titrations indicated a significant difference between the proton binding characteristics of the three samples. The smallest fraction had the greatest charge per unit mass whereas the largest fraction had the least charge: 2.0 and 1.0 meq g−1charge developed between pH 4 and 10, respectively. Experimental sorption studies with Cd and Cu indicated that metal binding per unit mass of SPM varied little between the three size fractions, although Cd was more strongly bound to the two smallest fractions. A simple one-site binding model provided a good description of the data and showed that the observed Cd and Cu sorption constants were consistent with literature values. The findings indicate that metal binding to the three size fractions is controlled mainly by the mass concentration and pH. The dependence on mass suggests that the surface area effective for binding is substantially independent of the size class. The results question the importance of the role played by the sub-micron fraction in trace metal binding by natural particle assemblages.