• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >The effects of soil organic matter heterogeneity on equilibrium sorption by soils and sediments.
【24h】

The effects of soil organic matter heterogeneity on equilibrium sorption by soils and sediments.

机译：土壤有机质非均质性对土壤和沉积物平衡吸附的影响。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Sorption of nonionic hydrophobic organic chemicals (HOCs) by soil is a phase distribution process in which HOCs are preferentially accumulated in naturally-occurring soil/sediment organic mater (SOM). The goal of this study was to identify and characterize which SOM component dominates the nonlinear and competitive sorption commonly observed for soils and sediments. I selected five different soils and sediments collected from relatively polluted areas. Different types of SOM were isolated from each sample, and were quantified and characterized using different physicochemical means. These isolated SOM fractions and the five original samples were used as the sorbents. Phenanthrene and naphthalene were selected as the target HOCs for examining single solute and bisolute sorption equilibria. The major findings include the following three aspects. Firstly, distinct nonlinear and competitive sorption equilibria were observed for all the sorbents. The results indicate that the particulate SOM (black carbon and kerogen) makes the major contributions to the overall nonlinear and competitive sorption exhibited by the bulk soils and sediments. Our finding that black carbon and kerogen are equally important in the nonlinear and competitive sorption is very different from the recent studies that described black carbon as the dominant SOM component but ignored the contribution from kerogen. Secondly, the results show that the sorption on humic acid (HA) is relatively less nonlinear with lower sorption capacities and that the solute-solute competition is comparably insignificant for HA. The less important role of HA in the overall sorption by soils is largely due to its low content in soils. This finding is surprisingly unexpected and is very different from a textbook notion that HA would be the major component of SOM and would be primarily responsible for the HOC sorption. Lastly, the results further revealed that the competitive sorption is not only a function of SOM heterogeneous properties, but is also depended up the loading sequence of the coexisting HOC solutes. When preloaded on a soil, the HOCs with larger molecular sizes may occupy the pore network, blocking a fraction of micropores with sizes smaller than the sorbates, lowering sorption capacities for incoming HOCs of smaller sizes.
机译：土壤对非离子疏水有机化学物质（HOC）的吸附是一种相分布过程，其中HOC优先积累在天然存在的土壤/沉积物有机物质（SOM）中。这项研究的目的是确定和表征哪种SOM成分主导了土壤和沉积物中通常观察到的非线性和竞争性吸附。我选择了从相对污染的地区收集的五种不同的土壤和沉积物。从每个样品中分离出不同类型的SOM，并使用不同的理化方法对其进行定量和表征。这些分离的SOM馏分和五个原始样品用作吸附剂。选择菲和萘作为目标HOC，以检查单溶质和双溶质的吸附平衡。主要发现包括以下三个方面。首先，观察到所有吸附剂具有明显的非线性和竞争性吸附平衡。结果表明，颗粒状SOM（黑碳和干酪根）对散装土壤和沉积物表现出的整体非线性和竞争性吸附作用起主要作用。我们的发现黑碳和干酪根在非线性吸附和竞争吸附中同等重要，这一发现与最近的研究将黑碳描述为主要的SOM成分但忽略了干酪根的贡献却大为不同。其次，结果表明，在腐殖酸（HA）上的吸附相对来说是非线性的，具有较低的吸附能力，并且溶质-溶质的竞争对HA而言微不足道。 HA在土壤的整体吸附中作用较小，主要是因为其在土壤中的含量较低。这一发现出乎意料地出乎意料，并且与教科书中HA可能是SOM的主要组成部分，并主要负责HOC吸附的观点大不相同。最后，结果进一步表明竞争吸附不仅是SOM异质性的函数，而且还取决于共存HOC溶质的加载顺序。当预先装载在土壤上时，分子尺寸较大的HOC可能占据孔网络，从而阻塞了一部分比吸附物小的微孔，从而降低了传入的较小尺寸HOC的吸附能力。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号