Carbon quantum dots (CQDs) are a class of zero-dimensional carbon nanomaterials recognized for their unique fluorescent properties, demonstrating significant potential across various fields. However, their application in the petroleum industry has not been adequately explored. This paper synthesized coal-based CQDs (coal dots) using a chemical oxidation method, achieving a mass yield of over 90 %. The coal dots had an average diameter of 2.4 nm and carried hydroxyl and carboxylic acid groups, making them hydrophilic and negatively charged. Their potential application as an oil displacement agent for enhanced oil recovery (EOR) was examined, resulting in an incremental oil recovery of 12.0 % in low-permeability rocks and 4.5 % in tight rocks. Our exploration of solid-fluid and fluid-fluid interactions suggested that wettability alteration, driven by the repulsive structural forces within the framework of surface forces, contributed to the EOR achieved with coal dots. The integration of coal dots into EOR can lead to the effective and sustainable development of both petroleum and coal resources.
Yi Wang,Jinrong Wu,Zhenxing Cao,Changshu Ma,Qingbo Tong,Jiangbo Li,Hanchao Liu,Jing Zheng,Guangsu Huang
Designing a homogeneous network is an efficient way to improve the mechanical properties of hydrogels. However, the homogeneous hydrogels usually have negligible notch-insensitivity due to the lack of effective energy dissipation, limiting their practical applications in many fields. Herein, we provide a straightforward method to prepare a category of tough and notch-insensitive polyacrylamide hydrogels crosslinked by a novel cross-linker with multiple vinyl functional groups (TA). Due to the multifunctionality of TA , a relatively uniform network with the coexistence of physical cross-links is constructed by the steric effect between chain radicals on TA molecules during the polymerization. The uniform network distributes stress evenly while the physical cross-links lead to viscoelastic dissipated energy under external force. As a result, the hydrogels achieve an ultrastretchability of 2400% and a tensile toughness of 4.33 MJ/m 3 . Even with a notch of 10 mm, the hydrogels can still be stretched to a strain of 20, indicating an impressive notch-insensitivity. Meanwhile, the hydrogels exhibit high fatigue resistance and good self-recovery. This research offers a facile strategy for designing high-performance hydrogels and may pave the way for their practical application in emerging fields, such as oil displacement agent and artificial cartilage .
危险品化学品经营许可证（带存储）