土壤有机质对拖尾期VOCs界面行为的影响及微观作用机理研究

The volatile organic compound (VOC) concentration in the soil during remediation follows a phenomenon referred to as tailing. In association with tailing, the removal efficienc is relatively low in the late stages of remediation. Tailing typically results in the presence of contaminant residues at levels far exceeding, which has become technological bottleneck and problem. Soil organic matter is an important factor influencing residual contamination. It is still unclear how organic matter affects residual VOCs at tailing. This project carries out a simulation experiment with mechanical soil aeration, and quantifies the effects of organic matter content and composition on residual contaminants at tailing stage during mechanical soil aeration. We build a numerical model to simulate the tailing and reveal regular pattern of residual VOCs. Adsorption/desorption batch experiments, equation fitting, and superposition methods are used, combined with advanced technologies such as nano-scale secondary ion mass spectrometry and laser scanning, etc. to characterize the distribution and microscopic structures of soil organic matter. We analyze the mechanism by which nonuniform soil organic matter and organic mineral interactions influence the non-linear interface behavior of VOCs. This project systematically details the effects of soil organic matter on the interface behavior of VOCs at tailing, and the microscopic mechanisms involved, taking three major parameters into consideration: content, composition, and form of occurrence. This research work will provide a theoretical and scientific basis for a better understanding of the impacts of soil organic matter on the characteristics of VOC residues at tailing. The results will be used to improve engineering technology parameter optimization.

挥发性有机物（VOCs）污染土壤修复普遍存在拖尾问题，拖尾期导致残留污染物超标已成为技术难点和瓶颈。研究表明，土壤有机质是影响污染物残留的主要因素，有机质诱发VOCs拖尾发生的微观机理及作用机制尚不清楚。本项目拟开展机械通风实验，研究有机质含量和组成对修复拖尾期污染物残留的影响，建立数值模型模拟修复过程中污染物的拖尾现象，揭示拖尾期VOCs的残留规律；通过液-固/气-固吸附解吸批实验，采用方程拟合和叠加计算等方法获取反应速率常数、反应级数和有机质-矿物相互作用力等参数，结合纳米二次离子质谱和激光共聚焦等手段对有机质赋存形态和微观结构的表征结果，分析土壤有机质非均匀性和有机质-矿物相互作用对VOCs非线性界面行为的影响机理。本项目从含量、组成和赋存形态系统阐述有机质对拖尾期VOCs界面行为的影响及微观作用机制，有助于完善土壤有机质和VOCs微界面作用机理，为工程技术参数优化提供科学依据。

挥发性有机物（VOCs）污染土壤修复普遍存在拖尾问题，拖尾期导致残留污染物超标已成.为技术难点和瓶颈。研究表明，土壤有机质是影响污染物残留的主要因素，有机质诱发VOCs拖.尾发生的微观机理及作用机制尚不清楚。本项目拟开展机械通风实验，研究有机质含量和组成.对修复拖尾期污染物残留的影响，建立数值模型模拟修复过程中污染物的拖尾现象，揭示拖尾.期VOCs的残留规律；通过液-固/气-固吸附解吸批实验，采用方程拟合和叠加计算等方法获取.反应速率常数、反应级数和有机质-矿物相互作用力等参数，结合纳米二次离子质谱和激光共.聚焦等手段对有机质赋存形态和微观结构的表征结果，分析土壤有机质非均匀性和有机质-矿.物相互作用对VOCs非线性界面行为的影响机理。本项目从含量、组成和赋存形态系统阐述有机.质对拖尾期VOCs界面行为的影响及微观作用机制，有助于完善土壤有机质和VOCs微界面作用机.理，为工程技术参数优化提供科学依据。