Search

Carbon Capture, Utilization, and Storage (CCUS) stands as one of the effective means to reduce carbon emissions and serves as a crucial technical pillar for achieving experimental carbon neutrality. CO2-enhanced oil recovery (CO2-EOR) represents the foremost method for CO2 utilization. CO2-EOR represents a favorable technical means of efficiently developing extra-low-permeability reservoirs. Nevertheless, the process known as the direct injection of CO2 is highly susceptible to gas scrambling, which reduces the exposure time and contact area between CO2 and the extra-low-permeability oil matrix, making it challenging to utilize CO2 molecular diffusion effectively. In this paper, a comprehensive study involving the application of a CO2 nanobubble system in extra-low-permeability reservoirs is presented. A modified nano-SiO2 particle with pro-CO2 properties was designed using the Pickering emulsion template method and employed as a CO2 nanobubble stabilizer. The suitability of the CO2 nanobubbles for use in extra-low-permeability reservoirs was evaluated in terms of their temperature resistance, oil resistance, dimensional stability, interfacial properties, and wetting-reversal properties. The enhanced oil recovery (EOR) effect of the CO2 nanobubble system was evaluated through core experiments. The results indicate that the CO2 nanobubble system can suppress the phenomena of channeling and gravity overlap in the formation. Additionally, the system can alter the wettability, thereby improving interfacial activity. Furthermore, the system can reduce the interfacial tension, thus expanding the wave efficiency of the repellent phase fluids. The system can also improve the ability of CO2 to displace the crude oil or water in the pore space. The CO2 nanobubble system can take advantage of its size and high mass transfer efficiency, among other advantages. Injection of the gas into the extra-low-permeability reservoir can be used to block high-gas-capacity channels. The injected gas is forced to enter the low-permeability layer or matrix, with the results of core simulation experiments indicating a recovery rate of 66.28%. Nanobubble technology, the subject of this paper, has significant practical implications for enhancing the efficiency of CO2-EOR and geologic sequestration, as well as providing an environmentally friendly method as part of larger CCUS-EOR. [ABSTRACT FROM AUTHOR]

A new thin film nanofibrous composite (TFNC) membrane for Cr (VI) removal was prepared by layer-by-layer assembly of chitosan/alginate on the surface of the electrospinning nanofibrous substrates. Scanning electron microscopy and static contact angle measurement were applied to characterize surface morphology and hydrophilicity, respectively. The mechanism of Cr (VI) removal and some factors, including positive/negative charge of terminating layer, bilayers, and Cr (VI) concentration, were investigated by a dead-end filter. These TFNC membranes exhibited a high Cr (VI) removal efficiency and an advantage of saving energy (the operating pressure was only 0.7 bar). The high efficiency was supposed to be the adsorption and Donnan effect which acted simultaneously for Cr (VI) removal. Besides, the research of recyclable property indicated that these TFNC membranes were easily regenerated and had a stable recycle property. Additionally, simple fabrication, low cost, and abundant species of polyelectrolytes showed these membranes had a good potential in heavy metal removal., INTRODUCTION The drinking water containing hexavalent chromium [Cr (VI)], accumulating in the food chain, is harmful to humans because of its carcinogenicity [1, 2], Therefore, how to remove Cr (VI) [...]

Abstract: Smart dual selective water/oil separation mode appears on an integrative mesh, which is fabricated via combined anodic oxidation and cathodic electrode‐deposition methods. Due to the different transport directions of oil and water, oil–water mixture can be separated completely using tailor‐made device. Extrusion pressure, acting as a critical pressure that depends on liquid surface tension, substrate microstructures, and wetting properties, can be a major factor to determine the passing or blocking mode. These remarkable water/oil separation properties of the integrative mesh can bring about novel applications in fluid rectifying, microchemical reaction manipulation, advanced separation, biomedical materials, purifying industrial wastewater, etc. [ABSTRACT FROM AUTHOR]

Nano heterostructures relying on their versatile construction and the breadth of combined functionality have shown great potential in energy storage fields. Herein, 2D sandwiched MoSe 2 /TiO 2- x /graphene nano heterostructures are designed by integrating structural and functional effects of each component, aiming to address the rate capability and cyclic stability of MoSe 2 for sodium ion capacitors (SICs). These 2D nano heterostructures based on graphene platform can facilitate the interfacial electron transport, giving rise to fast reaction kinetics. Meanwhile, the 2D open structure induces a large extent of surface capacitive contribution, eventually leading to a high rate capability (415.2 mAh g -1 @ 5 A g -1 ). An ultrathin oxygen deficient TiO 2- x layer sandwiched in these nano heterostructures provides a strong chemical-anchoring regarding the products generated during the sodiation/desodiation process, securing the entire cyclic stability. The associated sodiation/desodiation mechanism is revealed by operando and ex situ characterizations, which exhibits a strong solid electrolyte interphase (SEI) dependence. The simulations verify the dependent sodiation products and enhanced heterostructural chemical-anchoring. Assembled SICs based on these nano heterostructures anode exhibit high initial Coulombic efficiency, energy/power densities, and long cycle life, shedding new light on the design of nano heterostructure electrodes for high performance energy storage application., (© 2020 Wiley-VCH GmbH.)