天然黏土矿物和腐殖酸对纳米乳化油吸持的实验研究

为探讨天然黏土矿物及有机质对纳米乳化油在多孔介质中迁移滞留的影响,本文选取高岭石和蒙脱石这两种黏土矿物以及有机质的典型代表腐殖酸,开展了单一矿物、有机质及有机矿质复合物对纳米乳化油的吸持批实验研究,并运用比表面积全分析、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、X射线衍射(XRD)等技术手段探讨了吸持机理。实验结果表明,介质对纳米乳化油的吸持均符合Freundlich模型;单一矿物及腐殖酸对纳米乳化油的吸持能力表现为：蒙脱石>腐殖酸>高岭石,有机矿质复合样品的吸持能力表现为：蒙脱石-腐殖酸>高岭石-腐殖酸,且均大于其对应的单一样品,出现了“1+1>2”的现象,表明介质组成越复杂,对纳米乳化油的吸持滞留程度越大。进一步分析证实,纳米乳化油主要通过氢键和疏水作用吸持在矿物和腐殖酸表面,表面结构性质是高岭石和蒙脱石吸持过程中的主导因素,因此蒙脱石具有更强的吸持能力,而腐殖酸的吸持主要通过颗粒间聚集作用来实现;对于复合样品,吸持主要通过氢键、配体交换和疏水作用结合来实现。腐殖酸与矿物的复合会增加吸持位点并且增强矿物表面疏水性,从而促进吸持。腐殖酸与纳米乳化油的共吸...

Experimental study on the adsorption of nano emulsified oil by natural clay minerals and humic acid

In order to explore the influence of natural clay minerals and organic matter on the migration and retention of nano emulsified oil in porous media, kaolinite and montmorillonite, as well as humic acid, a typical representative of organic matter, were selected to carry out a batch of experiment on the adsorption of nano emulsified oil by single mineral, organic matter and organic mineral complex. The adsorption mechanism was discussed by means of full analysis of specific surface area, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD) and other techniques. The experimental results showed that the adsorption of nano emulsified oil by the media was in accordance with Freundlich model. The adsorption capacity of single mineral and humic acid to nano emulsified oil is as follows:montmorillonite>humic acid>kaolinite, the adsorption capacity of organic mineral composite samples is as follows:montmorillonite-humic acid>kaolinite-humic acid, which are larger than their corresponding single samples, and the phenomenon of "1+1>2" appears, indicating that the more complex the medium composition is, the greater the degree of adsorption and retention of nano emulsified oil is. Further analysis confirmed that nano emulsified oil was mainly adsorbed on the surface of minerals and humic acid through hydrogen bond and hydrophobicity, and the surface structure and properties are the dominant factors in the adsorption process of kaolinite and montmorillonite, so montmorillonite has stronger adsorption capacity, and the adsorption of humic acid is mainly realized through the aggregation between particles. For the composite samples, the adsorption is mainly realized by hydrogen bonding, ligand exchange and hydrophobicity. Combination of humic acid and mineral can increase the sorption sites and enhance the hydrophobicity of mineral surface, thus promoting the sorption. The co-adsorption and cumulative adsorption of humic acid and nano emulsified oil increased with the increase of emulsified oil concentration, which made the adsorption promotion of kaolinite humic acid stronger. With the increase of the concentration of emulsified oil, the humic acid and sorption sites that play the role of "bridge" decreased, which weakened the promoting effect of montmorillonite. The experimental results lay a foundation for further evaluation of migration and retention of nano emulsified oil in porous media.