Demulsification of Heavy Oil-in-Water Emulsion by a Novel Janus Graphene Oxide Nanosheet: Experiments and Molecular Dynamic Simulations

Abstract

Various nanoparticles have been applied as chemical demulsifiers to separate the crude-oil-in-water emulsion in the petroleum industry, including graphene oxide (GO). In this study, the Janus amphiphilic graphene oxide (JGO) was prepared by asymmetrical chemical modification on one side of the GO surface with n-octylamine. The JGO structure was verified by Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), and contact angle measurements. Compared with GO, JGO showed a superior ability to break the heavy oil-in-water emulsion with a demulsification efficiency reaching up to 98.25% at the optimal concentration (40 mg/L). The effects of pH and temperature on the JGO’s demulsification efficiency were also investigated. Based on the results of interfacial dilatational rheology measurement and molecular dynamic simulation, it was speculated that the intensive interaction between JGO and asphaltenes should be responsible for the excellent demulsification performance of JGO. This work not only provided a potential high-performance demulsifier for the separation of crude-oil-in-water emulsion, but also proposed novel insights to the mechanism of GO-based demulsifiers.

Fabrication of a Janus Copper Mesh by SiO2 Spraying for Unidirectional Water Transportation and Oil/Water Separation

“…11 Janus membranes with asymmetric surface wettability on two sides allow water droplets to transport unidirectionally from the hydrophobic side to the hydrophilic side while preventing the penetration of water droplets from the hydrophilic side to the hydrophobic side. 12−15 As a result of these fascinating and unique properties, Janus membranes exhibit great potential for applications in oil/water separation, 16−18 unidirectional liquid transportation, 12,19,20 fog collection, 21 membrane distillation, 22,23 sensors, 24 Janus liquid diode, 25,26 demulsification of oil, 27,28 etc. In recent years, numerous strategies have been applied to construct Janus membranes, including layer-by-layer preparation, 29 photochemical modification, 30 unilateral deposition, 31−33 etc.…”

“…Recently, oil/water separation technologies based on materials with unique wettability have attracted global attention as a result of their advantages of simplicity, recyclability, and inexpensive costs. − In comparison to traditional single- and switchable-wettability membranes for oil/water separation, , the Janus membranes have particular liquid transport behaviors because of their unique asymmetric wettability, showing excellent separation performances as well as expansion in the construction of three-dimensional (3D) porous materials with superwettability . Janus membranes with asymmetric surface wettability on two sides allow water droplets to transport unidirectionally from the hydrophobic side to the hydrophilic side while preventing the penetration of water droplets from the hydrophilic side to the hydrophobic side. − As a result of these fascinating and unique properties, Janus membranes exhibit great potential for applications in oil/water separation, − unidirectional liquid transportation, ,, fog collection, membrane distillation, , sensors, Janus liquid diode, , demulsification of oil, , etc. In recent years, numerous strategies have been applied to construct Janus membranes, including layer-by-layer preparation, photochemical modification, unilateral deposition, − etc. − For instance, Luo et al prepared a Janus Cu mesh decorated with Ni–NiO/Ni­(OH) 2 core–shell nanoparticles via selective electrodeposition.…”

Effect of Anionic Surfactants on the Oil–Water–Rock Interactions by an Improved Washburn Method

“…The development and utilization of petroleum resources has a pivotal position in the context of sustainable economic development. Low-permeability oil reservoirs in the underground are rich in reserves, but the exploitation effect is not ideal [ 1 , 2 , 3 ]. Due to the complex and variable structure of underground oil reservoirs in low-permeability reservoirs and the small size of reservoir pore throats, the rock–solution interaction has a large impact on the oil displacement efficiency.…”

Formulation of Spontaneous In Situ Emulsification Using Sodium Lauryl Sulfate Grafted Nanopyroxene for Enhanced Heavy Oil Recovery in Sandstone Reservoirs

“…Recently, some researchers have used amphiphilic graphene oxide (GO) derivatives and nanowire carbon nanotubes (CNTs) for EOR in sandstone reservoirs through the formation of spontaneous in situ emulsification. − The GO materials are considered an unconventional surfactant because of their edge-to-center distribution of functionality (hydrophilicity and hydrophobicity). For that purpose, researchers have observed the intensive interaction between GO and asphaltene to stabilize the heavy oil/water emulsions. − Nevertheless, the hydrophilicity of GO was reported to be higher than their hydrophobicity, resulting in poor interfacial activity . To overcome these issues, researchers have been intensively working on enhancing the amphiphilicity of GO through asymmetrical modification with alkylamine to formulate the Janus structure .…”