难沉降煤泥水多活性基团絮凝剂分子结构设计及作用机理研究

The difficult clarified coal slurry is a kind of complex dispersed system like colloid solution, which is difficult in flocculation sedimentation due to its characteristics of multi-component and microscale. Currently, the research on the difference in adsorption mechanism between the multi-component fine mineral particles surface and the active group of the flocculant is not profound enough. This project is a multidisciplinary study, in which a combination of theoretical calculation text analysis and experimental verification will be applied. Firstly, the advanced analytical techniques and quantum chemistry simulation will be employed to study the structures of the common exposed surface of mineral particles and the properties of the active sites on it, respectively. Then the common expose surface models of different minerals will be constructed using the Materials Studio, and the adsorption mechanisms and differences between different active groups and the different exposed surfaces of mineral particles will be revealed from the atomic/molecular level based on the density functional theory (DFT). Secondly, through the chemical resolution method, the chemical active fragment will be obtained, and after that the multi-active group polyacrylamide structure design and synthesis will be conducted on the organic synthesis platform, forming a new design method of multi-active group flocculant. Meanwhile, a test system for micro-cantilever adsorption process will be set up to study the adsorption mechanism and dynamic process characteristics of polyacrylamide adsorption on mineral particles. Finally, the flocculation experiments of coal slurry water with multi-active groups polyacrylamide will be carried out to verify the previous theoretical research. The research results can provide theoretical and technical support for the high-efficiency flocculation sedimentation and dewatering of the difficult clarified coal slurry.

难沉降煤泥水多组分微尺度近似胶体溶液的复杂分散体系特性导致其难以絮凝沉降，而目前对煤泥水中多组分微细矿物颗粒复杂界面与絮凝剂活性基团吸附作用机理的差异性等基础研究不够深入。项目拟通过多学科交叉融合，采用理论计算、测试分析与试验验证相结合的研究方法，通过先进的分析测试和量子化学模拟计算深入探究煤泥矿物颗粒常见暴露面结构及活性质点性质；构建不同矿物颗粒常见暴露面模型，基于密度泛函理论从原子/分子层面揭示不同活性基团在煤泥矿物颗粒不同暴露面的吸附机理及差异性；借助有机合成平台，通过化学拆分方法获取活性基团片段进行多活性基团聚丙烯酰胺结构设计优化及合成，形成多活性基团絮凝剂设计新方法；搭建微悬臂梁吸附过程测试系统，研究并阐明多活性基团聚丙烯酰胺在煤泥矿物颗粒表面吸附作用机制及动力学过程特性；开展多活性基团聚丙烯酰胺絮凝煤泥水试验验证。研究成果可以为难沉降煤泥水高效絮凝沉降脱水提供理论和技术支撑。

针对煤泥水中多组分微细矿物颗粒复杂界面与絮凝剂活性基团吸附作用机理的差异性等关键科学问题。项目通过多学科交叉融合，理论计算、测试分析与试验验证相结合的研究方法，深入探究了煤泥矿物颗粒常见暴露面结构及活性质点性质；构建了不同矿物颗粒常见暴露面模型，基于密度泛函理论从原子/分子层面揭示了不同活性基团在煤泥矿物颗粒不同暴露面的吸附机理及差异性；借助有机合成平台，优化设计并合成了疏水缔合P(AM-MAPTAC-TEMAc6)多活性基团聚丙烯酰胺，形成了多活性基团絮凝剂设计新方法；研究并阐明了多活性基团聚丙烯酰胺在煤泥矿物颗粒表面吸附作用机制及动力学过程特性。研究表明，高岭石（001）、（001 ̅）和（010）面等为高岭石晶体解理后的常见暴露面；经杂质取代后，杂质原子与相邻表面氧原子上的电荷重新排布，形成新的成键作用，相邻氧原子活性增强，形成高活性位点；PAM通过酰胺基的-C=O与高岭石颗粒表面的Al-OH进行吸附，PAM结构单元在高岭石表面的吸附能力强弱为P-DAC > P-AM > P-AA；吸附结构单元与高岭石表面的吸附能力强弱为P-MAPTAC > P-DMDAAC > P-DMC，氢键作用顺序为P-MAPTAC > P-DMC > P-DMDAAC，静电引力大小为P-MAPTAC > P-DMDAAC > P-DMC，疏水结构单元碳氟结构越多或碳链越长对水密度影响越大；P(AM-MAPTAC-TEMAc6)通过静电引力作用易吸附在水/高岭石 界面并主导整个吸附过程，氢键、静电引力和非键作用均随分子链数量增加而增强。P(AM-MAPTAC-TEMAc6)吸附结构单元的-N+(CH3)3基团能够突破水化膜阻碍，从而稳定吸附在高岭石表面；疏水结构单元的碳氟链显著降低周围水的密度，分子链间的弱静电斥力和缔合作用使其在水/高岭石界面上并未发生明显脱离行为。吸附作用增强会降低扩散速度导致桥连性能减弱，扩散范围和扩散速度共同决定桥连机制，吸附和桥连作用相互配合与影响。缔合作用则增强桥连机制，同时与疏水作用促进絮体的脱水和稳定性；沉降试验表明，新型多活性基团聚丙烯酰胺具有用量少，除浊效果显著，絮团致密，有利于难沉降煤泥水沉降脱水。研究成果可以为难沉降煤泥水高效絮凝沉降脱水提供理论和技术支撑。