Experimental study of the influence of silica nanoparticles on the bulk stability of SDS-foam in the presence of oil

Recent advances in nanomaterial-stabilized pickering foam: Mechanism, classification, properties, and applications

Pickering foam is a type of foam stabilized by solid particles known as Pickering stabilizers. These solid stabilizers adsorb at the liquid-gas interface, providing superior stability to the foam. Because of its high stability, controllability, versatility, and minimal environmental impact, nanomaterial-stabilized Pickering foam has opened up new possibilities and development prospects for foam applications. This review provides an overview of the current state of development of Pickering foam stabilized by a wide range of nanomaterials, including cellulose nanomaterials, chitin nanomaterials, silica nanoparticles, protein nanoparticles, clay mineral, carbon nanotubes, calcium carbonate nanoparticles, MXene, and graphene oxide nanosheets. Particularly, the preparation and surface modification methods of various nanoparticles, the fundamental properties of nanomaterial-stabilized Pickering foam, and the synergistic effects between nanoparticles and surfactants, functional polymers, and other additives are systematically introduced. In addition, the latest progress in the application of nanomaterial-stabilized Pickering foam in the oil industry, food industry, porous functional material, and foam flotation field is highlighted. Finally, the future prospects of nanomaterial-stabilized Pickering foam in different fields, along with directions for further research and development directions, are outlined.

Pickering foams and parameters influencing their characteristics

Pickering foams are available in many applications and have been continually gaining interest in the last two decades. Pickering foams are multifaceted, and their characteristics are highly dependent on many factors, such as particle size, charge, hydrophobicity and concentration as well as the charge and concentration of surfactants and salts available in the system. A literature review of these individual studies at first might seem confusing and somewhat contradictory, particularly in multi-component systems with particles and surfactants with different charges in the presence of salts. This paper provides a comprehensive overview of particle-stabilized foams, also known as Pickering foams and froths. Underlying mechanisms of foam stabilization by particles with different morphology, surface chemistry, size and type are reviewed and clarified. This paper also outlines the role of salts and different factors such as pH, temperature and gas type on Pickering foams. Further, we highlight recent developments in Pickering foams in different applications such as food, mining, oil and gas, and wastewater treatment industries, where Pickering foams are abundant. We conclude this overview by presenting important research avenues based on the gaps identified here. The focus of this review is limited to Pickering foams of surfactants with added salts and does not include studies on polymers, proteins, or other macromolecules.

Investigation of Nanoclay-Surfactant-Stabilized Foam for Improving Oil Recovery of Steam Flooding in Offshore Heavy Oil Reservoirs

This study presents a study of nanoclay-surfactant-stabilized foam to improve the oil recovery of steam flooding in offshore heavy oil reservoirs. The foam stability and thermal resistance studies were first performed to investigate the influence of nanoclay on the stability and thermal resistance properties of the foam system. Then, the sandpack flooding tests were conducted for investigating the resistance factor and displacement abilities by nanoclay-surfactant-stabilized foam. The results showed that the nanoclay-surfactant-stabilized foam has excellent foaming ability and foam stability at 300 °C, which can be used in steam flooding for offshore heavy oil reservoirs. The resistance factor is greater than 30 at 300 °C when the gas-liquid ratio ranges from 1 to 3, which indicated that the nanoclay-surfactant-stabilized foam has good performance of thermal resistance and plugging effect. The heterogeneous sandpack flooding test showed that the nanoclay-surfactant-stabilized foam can effectively divert the steam into the low-permeability area and improve the sweep efficiency, thus improving heavy oil recovery of steam flooding. Therefore, the nanoclay-surfactant-stabilized foam flooding has a great potential for improving oil recovery of steam flooding in offshore heavy oil reservoirs.