焦化废水中污染物在煤/水界面吸附的匹配机制和分子动力学研究

The experiment results showed that the “coal adsorption purification method” is effective for treating coking wastewater. The pollutants effectively adsorbed on the coal surface, when their spatial structures and surface properties matched each other. In this project, the interactions between pollutants and coal surface are studied from aspects including spatial structures, surface properties, adsorption thermodynamics and adsorption dynamics. Find out the activity resource of pollutants adsorption on coal surface in theory. Adsorption thermodynamic functions are measured by using microcalorimetric test technology. The adsorption rate constants and reaction series of pollutants adsorption on coal surface are calculated. The model of spatial structure matching between the pollutants and coal surface and the thermal dynamic role model are established based on the results of adsorption dynamics experiment based on QCM-D. The characterization system of “wetting” coal surface is established based on the coal wettability which obtained by using Washburn dynamic method. The molecular dynamics mechanism of the pollutants “wetting” coal surface and the “competitive adsorption” are revealed from the microscopic molecular aspect by using molecular dynamics simulation. The model of spatial structure matching between the pollutants and coal surface and the thermal dynamic role model are studied from two aspects of macro adsorption process and microscopic molecular interaction, the study results are significant for theoretical and practical application values in wastewater treatment by using “coal adsorption purification method”.

“煤吸附净化法”在处理焦化废水中取得良好的试验效果，吸附过程中，污染物在煤表面发生有效吸附需要在空间结构和表面性质上相互匹配。本项目从空间结构、界面性质、吸附热力学和吸附动力学方面研究污染物和煤表面之间相互作用，从理论上查明煤吸附污染物的活性来源，采用微量热测试技术，测定煤表面吸附污染物的吸附热力学函数值，计算得到吸附速率常数和吸附反应级数，结合基于QCM-D的吸附动力学试验建立污染物与煤表面结构相互作用的空间结构匹配模型和热动力学作用模型；通过Washburn 动态法对煤润湿性的测定，建立煤表面“去润湿”表征体系；通过分子动力学模拟，从微观分子层面上揭示污染物诱导煤表面“去润湿”和污染物之间“竞争吸附”的分子动力学作用机制。本课题从宏观吸附过程和微观分子界面作用两个层面研究污染物在煤表面吸附的匹配效应和分子动力学机制，研究结果对于“煤吸附净化法”的应用推广具有重要的理论意义。

“煤吸附净化法”在处理焦化废水中取得良好的试验效果，吸附过程中，污染物与煤空间结构和表面性质的相关作用机理仍需明确。本项目针对焦化废水中污染物在煤/水界面吸附的匹配机制和分子动力学机理问题，从空间结构、界面性质、吸附热力学和吸附动力学方面研究焦化废水中主要污染物和煤表面之间相互作用。项目主要取得了如下研究成果：1）通过吸附热力学研究揭示了煤对污染物的吸附机理，发现其以物理吸附为主，且为自发进行的放热反应。2）揭示了煤对典型污染物的吸附规律，其主要受污染物官能团和煤表面性质与表面官能团的影响。3）通过吸附动力学研究分析了煤对污染物的吸附速率变化和速率控制步骤，发现其吸附速率受液膜扩散和颗粒内部扩散共同控制。4）研究了煤粉的不同改性方法对污染物吸附效果和规律的影响，揭示了煤粉改性改性对吸附的作用机制，确定了改性煤粉的吸附过程和吸附机理。5）通过分子动力学模拟，揭示了苯系污染物诱导煤表面吸附的分子动力学机制， 确定了煤表面活性位点与污染物的匹配机制。项目研究成果为煤化工废水预处理提供了一条高效且低成本的技术路线，并为“煤吸附净化法”的工业应用推广提供了理论基础和数据支撑。