Nanofluids in recent years have shown great potential as a chemical enhanced oil recovery (EOR) technology, thanks to their excellent performance in altering interfacial properties. However, because of the great challenge in preparing stable systems suitable for an elevated temperature and a high salinity environment, expanding the application of nanofluids has been greatly restrained. In this work, a novel nanofluid was prepared by integrating positively charged amino-terminated silica nanoparticles (SiNP-NH 2 ) with negatively charged anionic surfactant (Soloterra 964) via electrostatic force. The resulted nanofluid could be stored at relatively high salinity (15 wt % NaCl solution) and high temperature (65 °C) for more than 30 days without aggregation. Successful coating of the surfactant on target SiNPs was verified by Fourier transform infrared spectrometry and the surface charge and size distribution. In addition, the potential of the nanofluid in recovering oil was investigated by analyzing the nanofluid/Bakken oil interfacial tension and the variation trend of the oil contact angle when brine was replaced by nanofluids. Experimental results showed that the water−oil interfacial tension of the Bakken crude oil decreased by 99.85% and the contact angle increased by 237.8% compared to the original value of 13.78 mN/m and 43.4°, respectively, indicating strong oil displacement efficiency and obvious wetting transition from oil-wet toward water-wet. Spontaneous imbibition tests conducted on Berea rocks showed that the nanofluid yielded a high oil recovery rate of 46.61%, compared to that of 11.30, 16.58, and 22.89% for brine, pure SiNP-NH 2 , and pure surfactant (Soloterra 964), respectively. In addition, when core flooding was applied, a total of 60.88% of the original oil in place could be recovered and an additional oil recovery of 17.23% was achieved in the chemical flooding stage. Moreover, a possible mechanism of the EOR using the nanofluid was proposed. Overall, the developed nanofluid is a promising new material for EOR.

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High-performance graphene aerogels with welldeveloped internal structures are generally obtained by means of introducing additive materials such as carbon nanotubes, cellulose, and lignin into the aerogel network, which not only enhances the cost but also complicates the preparation process. Therefore, tailoring the internal structure of pristine graphene aerogel in a feasible way to achieve high performance is of great significance to the practical applications. Herein, a novel cysteamine/L-ascorbic acid graphene aerogel (CLGA) was fabricated by a simple one-step hydrothermal method followed by freeze-drying. Through the creative combination of the reducing agent L-ascorbic acid and cross-linking agent cysteamine, a dual-network structure was constructed by both layered physical stacking and vertical chemical cross-linking. The addition of cysteamine not only enhanced the reduction degree but also assisted the formation of more vertical connections between graphene nanosheets, resulting in more abundant pores with smaller sizes compared with graphene aerogels prepared by the traditional hydrothermal reduction method. CLGA possessed an ultra-low density of 4.2 mg/cm 3 and a high specific surface area of 397.9 m 2 /g. As expected, this dual-network structure effectively improved the absorption capacity toward a variety of oil and organic solvents, with an outstanding oil absorption capacity up to 310 g/g. Furthermore, CLGA possessed good mechanical properties and oil/water selectivity. The absorbed oil could be recovered by both continuous absorption-removal process and mechanical squeezing, making the as-prepared aerogel superior absorbent material for a variety of applications, such as selective oil absorption and water treatment.