Kaolinite is widely distributed in shale formations. Kaolinite has two surface types, Si-O and Al-OH, and the two surfaces have different chemical properties. The surface wettability of kaolinite minerals is closely related to the occurrence of crude oil, the migration process of crude oil, and the filling process of crude oil. In this paper, we focus on the oil-water rock wettability of different alkane hydrocarbons on the different surfaces of kaolinite and construct a model of oil and water with variation of the alkane components on the surface of tetrahedral and octahedral kaolinite. Molecular dynamics methods were used to study the morphological changes in water clusters in different alkanes on different surfaces of kaolinite and to calculate the wetting angles. Studies have shown that the octahedral kaolinite surface is strongly hydrophilic, and the water clusters become monolayers adsorbed on the surface. Water easily displaces the oil on the surface and preferentially drives low carbon number alkanes. The tetrahedral siloxane kaolinite surface is oleophilic, the water molecules in CH-CH are clustered on the surface, and the wetting angle of the water cluster in the alkane increases with increasing carbon number. Water has difficulty displacing oil on this surface.
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http://dx.doi.org/10.1166/jnn.2021.18727 | DOI Listing |
Sci Rep
December 2024
Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK.
Wave ripples can provide valuable information on their formative hydrodynamic conditions in past subaqueous environments by inverting dimension predictors. However, these inversions do not usually take the mixed non-cohesive/cohesive nature of sediment beds into account. Recent experiments involving sand-kaolinite mixtures have demonstrated that wave-ripple dimensions and the threshold of motion are affected by bed clay content.
View Article and Find Full Text PDFEnviron Sci Process Impacts
December 2024
Anhui Bossco Environmental Protection Technology Co., Ltd, Ningguo, Anhui, 242301, China.
Contamination of heavy metals (HMs) has caused increasing concern due to their ecological toxicities and difficulties in degradation. The transport, retention, and release of HMs in porous media are highly related to their environmental fate and risk to groundwater. Column transport experiments and numerical simulations were conducted to investigate the retention and release behaviors of Cu, Pb, Cd, and Zn in the presence and absence of kaolin under varying ionic strengths and cation types.
View Article and Find Full Text PDFACS Omega
December 2024
Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing 163318, Heilongjiang, China.
In alkali/surfactant/polymer (ASP) flooding systems, alkalis react with clay minerals such as Illite, montmorillonite, and kaolinite, leading to reservoir damage and impacting oil recovery rates. Therefore, studying the dissolution effects of strong alkalis on clay minerals is crucial for improving oil recovery. This study uses Illite as a representative clay mineral and employs the ReaxFF reactive force field and molecular dynamics simulations to model its dissolution in NaOH solution.
View Article and Find Full Text PDFPLoS One
December 2024
School of Civil Engineering, Guizhou University, Guiyang, Guizhou Province, China.
In this paper, the road performance and mechanism of cement-phosphogypsum-red clay (CPRC) under dry and wet cycling were systematically investigated using 5% cement as curing agent, the mass ratio of phosphogypsum: red clay = 1:1, and 5% SCA-2 as water stabilizer. The road performance of dry and wet cycle mix was verified with the National Highway G210 Duyun Yangan to Yingshan Highway Reconstruction and Expansion Project as a test road to provide a scientific basis for the application of cement-phosphogypsum-red clay on roads. The results show that the cement-phosphogypsum-red clay unconfined compressive strength decreases with the increase of the number of wet and dry cycles, with a larger decay in the first three times and leveling off thereafter.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Chongqing Key Laboratory of Interface Process and Soil Health, College of Resources and Environment, Southwest University, Chongqing 400715, China.
In this study, the surface property parameters of non-swelling variable charge minerals, kaolinite and goethite, were determined using the ion-selective electrode method. The effects of experimental conditions, such as pH, ion concentration ratio, and liquid addition method, on the measurement results were clarified to provide a reference for accurately assessing the surface properties of variable charge materials. The research employed ion adsorption equilibrium experiments under varying pH levels, ion concentration ratios, and liquid addition methods.
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