Efficient demulsification of ultralow-concentration crude oil-in-water emulsion by three-dimensional superhydrophilic channels

Abstract

Efficient extraction of crude oil, the major energy resource of current concern and high demand worldwide, is of paramount importance in both energy and environmental fields. However, it remains a great challenge to separate the crude oil-in-water emulsions with an ultralow oil content of <200 ppm. Here, the three-dimensional and superwetting channels are developed by coating titanium foams with anodic TiO 2 nanotube arrays. The channels render superhydrophilic and underwater superoleophobic feature, which enables rapid formation of water channels that expel the oil droplets. A high separation efficiency of ∼96.8% and low total organic carbon content of ∼6 ppm are thus achieved for the ultralow-concentration crude oil-in-water emulsions. The pressure and time dependence of the separation process is systematically studied with a critical pressure of 12.25 kPa. Such a high performance is close to the theoretical limit imposed by the ultralow concentration, and shows obvious advances over either organic membranes or inorganic frameworks.

Surface Modification of TiO2 Nanotubes Prepared by Porous Titanium Anodization via Hydrothermal Reaction: A Method for Synthesis High-Efficiency Adsorbents of Recovering Sr Ions

“…In this study, TNTs with a high specific surface area were prepared on porous titanium by internal anodization, which is more suitable as a substrate than Ti foil. − Porous titanium has a porous structure and higher specific surface area, and the solution can flow through the inside, thus greatly increasing the effective contact area. Then, TNTs were subjected to appropriate HT reaction, loading Na + at the top and retaining the tubular structure at the bottom to ensure adhesion.…”

Dissecting the Chain Length Effect on Separation of Alkane-in-Water Emulsions with Superwetting Microchannels

“…In addition, although significant advances in oil/water separation have been achieved with organic membranes , and metal meshes, , the mechanical and chemical stability are still of key concern. To this end, porous titanium of high specific strength and large porosity is a promising alternative. , In this study, the effect of carbon chain length is systematically dissected by separating alkane-in-water emulsions with different superwetting microchannels. The alkane spans the entire liquid region with carbon numbers ranging from 6 to 16 and limits the separation with stabilized small droplets induced by long chains.…”

Universal Rapid Demulsification by Vacuum Suction Using Superamphiphilic and Underliquid Superamphiphobic Polyurethane/Diatomite Composites

“…The use of superwetted materials to separate oil and water has attracted attention recently because it meets most of these requirements. − Oil and water can be effectively separated because of their completely different wetting behaviors and motion on the same superwetted surface. , Filtration, coalescence, and adsorption are typically used for oil/water emulsion separation. ,− Filtration exploits the screening effect of porous superwetted materials, which hinder the passage of tiny droplets owing to surface repellency but allow the penetration of the continuous phase which is attracted. Coalescence is similar to filtration, but the continuous and dispersed phases both penetrate the porous superwetted materials and tiny droplets coalesce because of compression and dragging in microchannels, forming large droplets that are easily separated.…”