Electrospun Gelatin Membrane Cross-Linked by a Bis(diarylcarbene) for Oil/Water Separation: A New Strategy To Prepare Porous Organic Polymers

Recent developments in the application of membrane separation technology and its challenges in oil-water separation: A review

In the development and production process of domestic and foreign oil fields, large amounts of oil-bearing wastewater with complex compositions containing toxic and harmful pollutants are generated. These oil-bearing wastewaters will cause serious environmental pollution if they are not effectively treated before discharge. Among these wastewaters, the oily sewage produced in the process of oilfield exploitation has the largest content of oil-water emulsion. In order to solve the problem of oil-water separation of oily sewage, the paper summarizes the research of many scholars in many aspects, such as the use of physical and chemical methods such as air flotation and flocculation, or the use of mechanical methods such as centrifuges and oil booms for sewage treatment. Comprehensive analysis shows that among these oil-water separation methods, membrane separation technology has higher separation efficiency in the separation of general oil-water emulsions than other methods and also exhibits a better separation effect for stable emulsions, which has a broader application prospect for future developments. To present the characteristics of different types of membranes more intuitively, this paper describes the applicable conditions and characteristics of various types of membranes in detail, summarizes the shortcomings of existing membrane separation technologies, and offers prospects for future research directions.

Protocol for Preparing Synthetic Solutions Mimicking Produced Water from Oil and Gas Operations

Produced water (PW) is the water associated with hydrocarbons during the extraction of oil and gas (O&G) from either conventional or unconventional resources. Existing efforts to enhance PW management systems include the development of novel membrane materials for oil-water separation. In attempting to evaluate these emerging physical separation technologies, researchers develop various formulations of test solutions aiming to represent actual PW. However, there is no clear scientific guideline published in the literature about how such a recipe should be prepared. This article develops a protocol for preparing synthetic solutions representing the characteristics and behavior of actual PW and enabling the performance comparisons of different oil-water separation membranes at the bench scale level. In this study, two different brine recipes were prepared based on salts present in actual PW, crude oil was used as the hydrocarbon source, and a surfactant was added to disperse the oil into the aqueous phase. The recipe is accessible to the wider scientific community and was proven to be reproduceable, homogenous, stable, and comparable to actual PW field samples through analytical monitoring measurements and bench scale evaluations.

Decomposable Polyvinyl Alcohol-Based Super-Hydrophobic Three-Dimensional Porous Material for Effective Water/Oil Separation

The development of the oil industry brings the critical problem of ocean pollution by oil spill or fossil fuels. The use of materials for water/oil separation is one of the effective approaches to solve this crisis. Polyvinyl alcohol (PVA) has been used  to prepare water/oil separation materials. Currently, glutaraldehyde has been employed as the cross-linking agent, which is well known to be toxic and environmentally unfriendly. Moreover, it is difficult to deal with the disposal of the Across-linked material. Here, we propose a strategy of fabricating macroporous material which was prepared by PVA and sodium silicate (Na₂SiO₃) in aqueous solution. Following through with the one-step method of sol-gel reaction of hydroxyl groups with trimethoxy(octadecyl)silane, the low surface energy substance was grafted on the macroporous material and a super-hydrophobic macroporous membrane for water/oil separation was prepared. As oil sorbent, the as-prepared dried super-hydrophobic PVA/Na₂SiO₃ porous materials (PSD6S) have the adsorption capacity of 1.8-7.0 g/g for oil uptake, which depends on the type of oil liquid. Typically, the separation efficiency of this material could reach more than 99% even after 10 times of use without the help of ambient pressure. It is noteworthy that the as-prepared samples could be easily decomposable and dissolvable completely in acidic medium at a rapid rate.